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WO2019163114A1 - Power module and switching power supply - Google Patents

Power module and switching power supply Download PDF

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Publication number
WO2019163114A1
WO2019163114A1 PCT/JP2018/006835 JP2018006835W WO2019163114A1 WO 2019163114 A1 WO2019163114 A1 WO 2019163114A1 JP 2018006835 W JP2018006835 W JP 2018006835W WO 2019163114 A1 WO2019163114 A1 WO 2019163114A1
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WO
WIPO (PCT)
Prior art keywords
circuit
switching
power module
switching element
snubber
Prior art date
Application number
PCT/JP2018/006835
Other languages
French (fr)
Japanese (ja)
Inventor
亘 宮澤
茂 久田
雄司 森永
淳志 久徳
Original Assignee
新電元工業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by 新電元工業株式会社 filed Critical 新電元工業株式会社
Priority to PCT/JP2018/006835 priority Critical patent/WO2019163114A1/en
Publication of WO2019163114A1 publication Critical patent/WO2019163114A1/en

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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00Details of apparatus for conversion

Definitions

  • the present invention relates to a power module and a switching power supply.
  • Recent power electronics has been switching to high speed by developing power device technology.
  • Power MOSFET oxide semiconductor field effect transistor
  • IGBT insulated gate bipolar transistor
  • high-speed power devices such as GaN (gallium nitride) and SiC (silicon carbide), which are attracting attention as next-generation devices, are applied.
  • GaN gallium nitride
  • SiC silicon carbide
  • high switching speed may cause stress by applying a large surge voltage to the output switching waveform of the switching element at the turn-off timing of the switching element.
  • the switching speed may increase. There was a case where control was impossible due to excitation oscillation.
  • Patent Document 1 discloses a method for reducing a surge voltage by mounting a switching element, a snubber capacitor, a snubber resistor, and a snubber capacitor on a wiring formed on the same substrate by using a bump, etc.
  • Patent Document 2 includes a semiconductor chip, upper and lower heat sinks, a multilayer wiring bus bar in which various terminals and wires are integrated, a control terminal, an element relay electrode, a plate, and the like, and switching elements are arranged in a multilayer in the module.
  • a method for reducing parasitic inductance is disclosed.
  • the reduction of parasitic inductance due to the multilayer structure in the module is also disclosed in Patent Document 3.
  • the high-potential side switching element and the low-potential side switching element are embedded in the same layer of the multilayer substrate, and these formed layers are arranged to be insulated from each other.
  • the high-potential side switching element and the low-potential side switching element are both vertical devices.
  • a wiring layer is provided on the upper surface of these switching elements, and a snubber circuit is connected to the surface of the multilayer substrate via via conductors.
  • the snubber circuit is arranged so as to run parallel to the electrical path connecting the wiring layers in the shortest distance.
  • the length of the via conductor which is a connection means between the wiring layer and the snubber circuit, is sufficiently shorter than the distance between the via conductor and wiring layer connection point and the via conductor and wiring layer connection point. .
  • Patent Document 4 discloses a circuit configuration technique capable of reducing the parasitic inductance of the main circuit of the power supply device.
  • the field effect transistors of the first semiconductor chip and the second semiconductor chip are formed of n-channel vertical field effect transistors, and the surface on which the source electrode of the first semiconductor chip is disposed and the drain electrode of the second semiconductor chip are disposed.
  • the drain electrode of the first semiconductor chip has a first lead plate connected to an external terminal for supplying input power
  • the source electrode of the chip has a second lead plate connected to an external terminal for supplying a reference potential.
  • a capacitor is provided that is electrically connected between the first lead plate and the second lead plate.
  • the capacitor has one of the pair of electrodes joined to the first lead plate, and the other of the pair of electrodes is the second lead plate. And is mounted on the surface of the package.
  • switching power supplies require next-generation devices such as SiC and GaN to perform high-speed switching at higher voltages and larger currents, and it is difficult to sufficiently suppress surge generation and self-excited oscillation with the conventional structure. there were. Further, since the components are mounted on the same plane, there is a problem that the wiring becomes long and the parasitic inductance increases.
  • the conventional switching power supply composed of discrete components has a problem that the wiring length cannot be shortened and the switching operation becomes unstable due to parasitic inductance or the like. Therefore, the power module takes measures such as reducing parasitic inductance as much as possible to stabilize the operation.
  • the switching operation varies depending on the input / output conditions and the design conditions, depending on the constants of the electronic components provided inside, the switching operation may become unstable, and the input / output conditions and the design conditions are limited. was there
  • a snubber circuit is provided inside the module as a measure against noise, but the capacitance value and resistance value such as a snubber capacitor and snubber resistance are fixed when designing the circuit. For this reason, when mounted, there is a problem that freedom of selection corresponding to noise is hindered and the reliability of the module is lowered.
  • the structure in which the snubber circuit is provided inside the module requires the area where the snubber circuit is mounted and the wiring to connect to the snubber circuit.
  • the wiring distance of other parts is increased to generate more parasitic inductance, and to the snubber circuit.
  • An object of the present invention is to provide a power module configuration that solves these problems and suppresses the generation of noise.
  • the power module according to the present invention includes an in-case electronic component including at least a switching element or a rectifying element, a mold case in which the in-case electronic component is resin-sealed, and two or more exposed on the outer surface of the mold case External electrodes and conductive members or vias that electrically connect the in-case electronic components and the external electrodes.
  • the electronic components adapted to the design conditions from the outside of the mold case are mounted on two or more external electrodes exposed on the outer surface of the mold case. It becomes a circuit that demonstrates the intended function.
  • the power module according to the present invention includes an in-case electronic component including at least a switching element or a rectifying element, a mold case in which the in-case electronic component is resin-sealed, and two or more exposed on the outer surface of the mold case External electrodes, conductive members or vias that electrically connect the in-case electronic components and the external electrodes, and external electronic components that are electrically connected to the external electrodes.
  • the externally mounted electronic component may include at least a capacitor.
  • the externally mounted electronic component may be connected to a protection circuit that absorbs a surge caused by a parasitic component of the switching waveform.
  • the protection circuit may be a snubber circuit including at least one of a resistor, a diode, and a capacitor.
  • the externally mounted electronic component may include at least a semiconductor element.
  • the semiconductor element may include an avalanche surge diode for absorbing surge.
  • the switching element or the rectifying element may include an element made of gallium nitride, gallium oxide, or silicon carbide.
  • a normally-on type semiconductor and a normally-off type semiconductor may be cascode-connected.
  • the power module according to the present invention can be used as a switching power supply.
  • the power module according to the present invention includes an in-case electronic component including at least a switching element or a rectifying element, a mold case in which the in-case electronic component is resin-sealed, and two or more exposed on the outer surface of the mold case External electrodes and conductive members or vias that electrically connect the in-case electronic components and the external electrodes. If the circuit by the electronic components mounted in the case is not a completed circuit, the electronic components adapted to the design conditions from the outside of the mold case are mounted on two or more external electrodes exposed on the outer surface of the mold case. It becomes a circuit that demonstrates the intended function.
  • the circuit using the electronic components mounted in the case does not require a space for mounting electronic components adapted to the design conditions from the outside of the mold case, and the electronic components can be arranged at high density.
  • the wiring pattern can be shortened and the parasitic inductance is minimized.
  • the present invention can be widely applied. For example, it can be applied to a three-phase inverter module.
  • the power module according to the present invention includes an in-case electronic component including at least a switching element or a rectifying element, a mold case in which the in-case electronic component is resin-sealed, and two or more exposed on the outer surface of the mold case External electrodes, conductive members or vias that electrically connect the in-case electronic components and the external electrodes, and external electronic components that are electrically connected to the external electrodes.
  • a circuit with an electronic component mounted in the case, and a circuit that finally exerts the intended function by the external mounted electronic component adapted to the design conditions from the outside of the mold case to two or more external electrodes exposed on the outer surface of the mold case Become.
  • a circuit using electronic components mounted in the case does not require a space for mounting electronic components adapted to the design conditions from the outside of the mold case, electronic components can be arranged at high density, and the wiring pattern can be shortened. . As a result, the parasitic inductance is minimized.
  • an electronic component mounted via the external electrode can be arbitrarily selected, and the degree of freedom in design is improved.
  • the externally mounted electronic component may be connected to a protection circuit that absorbs a surge caused by a parasitic component of the switching waveform.
  • a protection circuit that absorbs surges caused by parasitic components of the switching waveform.
  • the protection circuit may be a snubber circuit including at least one of a resistor, a diode, and the capacitor.
  • a first snubber circuit having a capacitor and a diode, and a second snubber circuit having a capacitor, a diode, and a resistor are connected as a surge absorption protection circuit.
  • the wiring pattern between the power module and the electronic component connected to the external electrode can be shortened. For this reason, it becomes a structure which minimizes a parasitic inductance, and can provide the power module and switching power supply which enable stable switching operation
  • An externally mounted electronic component may be included as at least a semiconductor element, and a protective circuit may be included in the switching element.
  • the semiconductor element is a diode, a thyristor, a server absorber, a power Zener, or the like.
  • the semiconductor element includes an avalanche surge diode for surge absorption.
  • the protection circuit is configured by connecting a surge absorption protection circuit including an avalanche surge breakdown diode.
  • the electronic components mounted in the case include at least a switching element or a rectifying element.
  • the switching element or rectifying element may include an element made of gallium nitride, gallium oxide, or silicon carbide.
  • Switching elements or rectifying elements are elements that contain gallium nitride, gallium oxide, or silicon carbide. Therefore, not only can the switching speed be increased to achieve higher efficiency, but also higher voltage can be accommodated, and more stable. It is possible to provide a power module and a switching power supply that enable efficient switching operation.
  • a normally-on type semiconductor and a normally-off type semiconductor may be cascode-connected.
  • GaN and SiC have advantages such as high speed and high withstand voltage, they may be configured as normally-on type, so normally-off type operation is required from the viewpoint of fail-safe.
  • a normally-off type can be realized by a technique of cascading normally-off MOSFETs. Therefore, it is possible to provide a power module and a switching power supply that enable a stable switching operation with low noise.
  • the power module can be used as a switching power supply. It is possible to provide a switching power supply that has a structure in which the parasitic inductance is minimized and enables a stable switching operation.
  • FIG. 5 is a diagram for explaining an example in which a snubber resistor, a snubber capacitor and a snubber diode are used in the protection circuit, and the snubber resistor and the snubber capacitor are mounted inside the module and the snubber diode is connected to an external electrode.
  • a power module includes an in-case electronic component including at least a switching element or a rectifying element, a mold case in which the in-case electronic component is resin-sealed, and two or more external electrodes exposed on the outer surface of the mold case And a conductive member or via for electrically connecting the in-case mounted electronic component and the external electrode.
  • FIG. 1 shows a structure in which an external electrode 14-1 and an external electrode 14-2 are provided on the bottom surface (back surface) of a power module 10 according to the present invention.
  • the external electrode 14-1 and the external electrode 14-2 have a pad shape for soldering and connecting electrical components.
  • the external electrode 14-1 and the external electrode 14-2 are connected to electronic components mounted inside the mold case 12 through conductive members or vias.
  • the lead 16 is a pin for inserting the power module 10 into the printed board, and is fixed with solder.
  • a power circuit in which a plurality of power semiconductors are combined and integrated is mounted inside the power module 10.
  • the external electrode 14-1 and the external electrode 14-2 are part of the components constituting the power circuit. Is connected.
  • FIG. 2 is an external view of a power module 20 equipped with an external electronic component according to the present invention.
  • In-case electronic component including at least a switching element or a rectifying element, a mold case 12 in which the in-case electronic component is resin-sealed, two or more external electrodes exposed on the outer surface of the mold case 12, and in-case mounting A conductive member or via for electrically connecting the electronic component and the external electrode, and an externally mounted electronic component (for example, a capacitor) electrically connected to the external electrode are provided.
  • the external electronic component-mounted power module 20 is simply referred to as the power module 20.
  • a capacitor 22 which is an externally mounted electronic component is connected to the external electrode 14-1 and the external electrode 14-2.
  • the capacitor 22 suppresses noise of the switching element, that is, surge and harmonic ringing.
  • a plurality of capacitors 22 may be mounted depending on the capacity. However, since the height is limited, when one capacitor 22 has a large capacity and a large external shape, a spacer for adjusting the height is attached to the lead 16. May be. Thereby, the height for electronic component mounting is ensured, and it can be completed with one electronic component.
  • FIG. 3 shows an example of a power circuit mounted in the mold case 12 of the power module 20 to which the external electrodes 14-1 and 14-2 are connected.
  • FIG. 3 shows an example of a switching circuit 30 in which two switching elements are connected in series.
  • the switching element is, for example, a power MOSFET (Metal-Oxide-Semiconductor, Field-Effect-Transistor).
  • the H source 38 of the high side switching element 32 and the L drain 44 of the low side switching element 40 are connected.
  • the switching circuit 30 is formed by connecting a high-side switching element 32 and a low-side switching element 40 in series, and both ends of the high-side switching element 32 and the low-side switching element 40 connected in series, that is, an H drain 36 and an L source. 46 is connected to the external electrodes 14-1 and 14-2.
  • a capacitor 22 is connected to the external electrodes 14-1 and 14-2 to reduce noise during switching. Since the capacitor 22 is connected from the outside of the mold case 12, an arbitrary capacity can be selected according to the design conditions.
  • the H gate 34 of the high side switching element 32 and the L gate 42 of the low side switching element 40 are connected to a gate drive circuit (not shown), and are controlled to be repeatedly turned on / off alternately. Since the high-side switching element 32 and the low-side switching element 40 are alternately turned on / off, this is called a synchronous rectification method.
  • FIG. 4 shows another example of the power circuit mounted inside the mold case 12.
  • FIG. 4 shows a three-phase inverter circuit in which a power circuit in the power module 20-1 is mounted by connecting three switching circuits 30-1, 30-2 and 30-3 in parallel.
  • the three-phase inverter circuit generates a three-phase voltage waveform from a DC power supply, and is used as a power circuit for driving a three-phase AC motor, for example.
  • a capacitor 22 is connected in parallel to the three-phase inverter circuit, and a voltage waveform is formed in which ripples are reduced during switching and the influence of noise is suppressed.
  • the switching circuit 30 and the three-phase inverter circuit in which the switching elements are connected in series have been shown.
  • the present invention is not limited to this example.
  • a switching circuit using a rectifying element may be used.
  • FIG. 5 shows an example of a switching circuit using a switching element and a rectifying element.
  • FIG. 5A shows a switching circuit 30-4 in which the low-side switching element 40 is replaced with a switching diode 48 that is a rectifying element in the switching circuit 30 shown in FIG.
  • FIG. 5B shows a switching circuit 30-5 in which the high-side switching element 32 in the switching circuit 30 shown in FIG. 3 is replaced with a switching diode 48 that is a rectifying element.
  • the switching diode 48 has a low recovery current and a low forward voltage, and it may be preferable to use a Schottky diode such as SiC.
  • a switching circuit using a switching element and a rectifying element is called an asynchronous rectifying system as opposed to a synchronous rectifying system.
  • the switching circuit 30-4 shown in FIG. 5A no current flows through the switching diode 48 when the high-side switching element 32 is on, and no current flows through the switching diode 48 when the high-side switching element 32 is off.
  • a forward current flows.
  • the asynchronous rectification method is inferior to the synchronous rectification method, and the output voltage cannot be actively controlled. When the load current is reduced, high-frequency ringing may occur, but there is only one switching element. When applied to the control circuit, the control circuit can be easily configured.
  • the switching circuit 30-4 shown in FIG. 5A is used as a switching circuit for a step-down DC converter
  • the switching circuit 30-5 shown in FIG. 5B is used as a switching circuit for a step-up DC converter.
  • the basic circuit configuration of the step-down DC converter and the step-up DC converter is the same in the synchronous rectification method. One of them can be used as input and the other as output, and negative feedback control is performed from the output side to control the timing of each switch. However, the only difference is that the current is controlled in the opposite direction.
  • the switching diode 48 since the switching diode 48 flows only in the forward current, the step-down DC converter and the step-up DC converter are different circuits.
  • the switching circuit 30 Since the switching circuit 30 turns on / off the switching element at a high frequency, noise often becomes a problem.
  • a power transistor is used as the switching element, and a surge voltage or a ringing voltage (surge / ringing voltage) is generated when the switching element is off.
  • a surge / ringing current i flows through the switching circuit 30, which flows into a high-frequency ringing loop of a DC converter using the switching circuit 30, and a surge / ring of L ⁇ di / dt due to the parasitic inductance L existing in the loop. Ringing voltage is generated.
  • t is time. This causes noise at the input capacitor terminal in the DC converter, causes noise at the switch node, and is transmitted to the output terminal and other devices through the parasitic capacitance of the inductor and the substrate.
  • the switching circuit 30 in which switching elements are connected in series is used in a synchronous rectifier converter in a switching power supply.
  • the basic circuit and noise are taken into consideration by taking a synchronous rectifier step-down DC / DC converter as an example.
  • the equivalent circuit will be described.
  • FIG. 6 shows a basic circuit 50 of a synchronous rectification step-down DC / DC converter.
  • An input capacitor 54 is connected in parallel with the input voltage 52.
  • the average value of the input current is reduced according to the transformation ratio, but the same current as the output current flows instantaneously, and this is averaged by the input capacitor 54.
  • the input voltage 52 is connected to the switching circuit 30, and the high-side switching element 32 and the low-side switching element 40 are controlled to be turned on / off alternately by a pulse signal from the gate drive circuit 56.
  • the output switching waveform at the midpoint between the high-side switching element 32 and the low-side switching element 40 becomes a pulse waveform corresponding to the switching frequency.
  • the output switching waveform at the intermediate point between the high-side switching element 32 and the low-side switching element 40 becomes a DC voltage through a smoothing circuit including an output inductor 58 and an output capacitor 60 connected in series, and is supplied to the load 62.
  • the noise of the synchronous rectification step-down DC / DC converter is generated by the surge / ringing voltage generated when the switching element is turned off, the parasitic inductance of the wiring, and the parasitic capacitance of the switching element.
  • An equivalent circuit in consideration of noise due to the parasitic inductance of the wiring and the parasitic capacitance of the switching element will be described below.
  • FIG. 7 shows an equivalent circuit 66 in consideration of parasitic inductance and parasitic capacitance. Since the switching element depends on the type of element to be selected, a power MOSFET is used here, the high side switching element 32 is a high side power MOSFET 80, and the low side switching element 40 is a low side power MOSFET 82.
  • Parasitic elements are the parasitic inductance 70-1 and ESR (Equivalent Serial Resistance) in the input capacitor 54. ESR is also present in the wiring, and in FIG. In the power MOSFET, the mirror capacitance and the gate capacitance are not considered, and the body diode and the parasitic capacitance are used as parasitic elements. In the high-side power MOSFET 80, the body diode 76-1 and the parasitic capacitance 74-1 are shown in the equivalent circuit, and in the low-side power MOSFET 82, the body diode 76-2 and the parasitic capacitance 74-2 are shown as parasitic elements.
  • a parasitic capacitance between the windings of the inductor and a parasitic capacitance of the substrate pattern are generated and are shown as a stray capacitance 78.
  • the parasitic inductance 70-2 and the ESR 72-2 are parasitic elements. Parasitic inductances are also generated in wiring, layout, vias, etc., but are shown by wiring parasitic inductances 70-2, 70-3, 70-4 in FIG.
  • the on / off of the high-side power MOSFET 80 and the low-side power MOSFET 82 is controlled by the switching waveform of the gate drive circuit 56, but high-frequency noise is likely to occur mainly when the high-side power MOSFET 80 and the low-side power MOSFET 82 are turned off.
  • the high side power MOSFET 80 is turned on, a current flows from the input voltage 52 through the high side power MOSFET 80 so as to cancel the return current of the low side power MOSFET 82.
  • This recovery current is a short-circuit current i that flows in a loop (see the broken line in FIG. 7) composed of the input capacitor 54, the high-side power MOSFET 80, and the low-side power MOSFET 82, and energy is accumulated in all parasitic capacitances existing in the loop.
  • a surge voltage depending on di / dt is generated in the input capacitor 54, and a ringing voltage of dV / dt corresponding to the voltage V is generated in the high-side power MOSFET 80 and the low-side power MOSFET 82.
  • the high-frequency ringing current that flows through the loop generates a magnetic flux that depends on the area of the loop, and this magnetic flux is radiated to the outside, causing electromagnetic induction in the stripline and loop of the equipment substrate as an electromagnetic wave.
  • the switching circuit 30 is provided with a surge absorbing element and a snubber circuit for the purpose of suppressing a surge / ringing voltage. Furthermore, to protect the switching element from overcurrent, for example, in a synchronous rectification step-down DC converter, if an overshoot occurs due to a transient response or the like in the output voltage, the output is sunk from the output to reverse the current and regenerate to the input for output. A regenerative circuit that performs an operation of forcibly lowering the voltage is used. In addition to these protection circuits, overcurrent protection by a gate drive signal is performed.
  • FIG. 8 is a block diagram showing the switching circuit 30 used in the DC / DC converter, the gate drive circuit 56 that controls the switching elements of the switching circuit 30 by turning on / off, and the protection circuit 90 of the switching circuit 30. is there.
  • the high-side power MOSFET 80 and the low-side power MOSFET 82 in the switching circuit 30 are alternately turned on / off.
  • the gate drive circuit 56 provides a dead time to prevent the gate of the switching element of the switching circuit 30 from being erroneously turned on by dv / dt generated during switching that is turned on / off. Heating due to flow and switching element destruction are prevented.
  • FIG. 9 is a diagram for explaining dead time.
  • the high side gate signal is input to the gate of the high side power MOSFET 80, and the low side gate signal is input to the gate of the low side power MOSFET 82.
  • the dead time is provided with a first dead time that is delayed for a predetermined time after the high-side gate signal is turned off, and the low-side gate signal is turned on. To do.
  • a second dead time that is delayed for a predetermined time is provided to turn on the high-side gate signal.
  • Dead time must be set longer than the switching time of the switching element. Even if the dead time is sufficient, a minute pulse current flowing through the mirror capacitance of the switching element flows. If the dead time is insufficient, a large short-circuit current flows, causing noise and destabilizing the switching operation regardless of the destruction of the switching element.
  • the switching circuit 30 is stably operated by the gate drive circuit 56 and the protection circuit 90, but the wiring that electrically connects these circuits needs to be as short as possible to suppress the parasitic inductance.
  • the surge absorbing element and the snubber circuit are preferably arranged near the switching element in order to suppress noise generated in the switching element of the switching power supply.
  • FIG. 10 shows an electrical equivalent circuit in consideration of the parasitic inductance 70-10 generated in the wiring of the snubber circuit 92 when the snubber circuit 92 is connected to the switching circuit 30. Since wiring is required for mounting the snubber circuit 92, a new parasitic inductance 70-10 is generated. Furthermore, if the snubber circuit 92 is to be mounted on the same printed circuit board as other circuit elements, the arrangement of the other circuit elements also changes, the wiring must be lengthened, and the parasitic inductance increases.
  • the protection circuit can be mounted by connecting to the external electrodes 14-1 and 14-2, the wiring for connecting the protection circuit can be shortened and generation of new parasitic inductance can be suppressed. it can. Furthermore, it is not necessary to lengthen the wiring without changing the arrangement of other circuit elements.
  • Protective circuit that absorbs surges caused by parasitic components of the switching waveform is connected as external electrode externally mounted components.
  • the semiconductor circuit is used for this protection circuit, and an avalanche diode is used for surge absorption.
  • the protection circuit is a snubber circuit including at least one of a resistor, a diode, and a capacitor.
  • the surge absorbing element and the snubber circuit 92 can be connected to and mounted on the external electrodes 14-1 and 14-2 exposed on the outer surface of the mold case 12.
  • the space for mounting the snubber circuit 92 on the printed circuit board is not required, the wiring to the snubber circuit 92 can be shortened, and there is no need to change the arrangement and wiring of other circuit elements.
  • the parasitic element has a parasitic inductance 70-10 in the wiring of the snubber circuit 92, but since the distance to the external electrodes 14-1 and 14-2 can be shortened, the value of the parasitic inductance 70-10 is small.
  • the snubber circuit 92 that absorbs the ringing voltage has a calculation formula based on parasitic inductance and parasitic capacitance, and can be simulated. Conventionally, a snubber circuit configuration and electronic parts are selected by this simulation means and mounted on a printed circuit board and packaged. Even if an electronic component is mounted with its value corrected by actual measurement, when it is actually used, various parasitic elements are generated, and the snubber circuit needs to be further corrected, that is, a more optimal electronic component is required. However, the optimum snubber circuit 92 actually measured according to the mounting state cannot be selected, and the degree of design freedom is limited.
  • the external electrode for the snubber circuit is provided on the outer surface of the mold case, and can be freely designed while measuring the surge / ringing voltage in the mounting state that the user actually uses. Therefore, it is possible to suppress the optimum surge / ringing voltage.
  • the surge / ringing voltage for example, using an oscilloscope with a bandwidth of 1 GHz, using a passive probe and mount jack, and using an FET probe. To do. Based on the result, the snubber circuit 92 for suppressing the surge / ringing voltage can be designed and mounted. 0901f02-formula01.gif0901f02-formula01.gif
  • the protection circuit that suppresses the surge / ringing voltage is an electric circuit composed of an electronic component for overvoltage detection protection and an electronic component for noise removal, and various forms are conceivable. The main examples are described below.
  • FIG. 11 shows an example in which a surge absorbing avalanche diode 94 is connected to external electrodes 14-1 and 14-2.
  • the avalanche diode 94 is connected to the H drain 36 and the L source 46 via both ends of the high side switching element 32 and the low side switching element 40 connected in series, that is, the external electrodes 14-1 and 14-2.
  • the avalanche diode 94 is a clamper that causes an avalanche breakdown at a specific reverse voltage and protects the circuit from an overvoltage.
  • power modules are required to switch a high voltage at high speed.
  • a silicon avalanche diode has a breakdown voltage of several kV.
  • the avalanche diode is intended to detect and cut the peak value of the surge voltage (or current) by paying attention to the time domain of the output switching waveform.
  • the maximum value of the voltage (or current) to be cut is determined by the breakdown voltage of the avalanche diode.
  • the frequency characteristic depends on the recovery time of the avalanche diode 94.
  • a snubber diode and a snubber Zener diode may be connected in series in the reverse direction in addition to the avalanche diode.
  • FIG. 12 shows an example in which the snubber circuit 92-1 is a snubber resistor 100 (hereinafter, an electronic component used in the snubber circuit 92 is named with a snubber) and a snubber capacitor 102.
  • the snubber circuit 92-1 in which the snubber resistor 100 and the snubber capacitor 102 are connected in series is a kind of low-pass filter, and the cut-off frequency is required to be equal to or lower than the high-frequency ringing frequency.
  • the use of only the snubber capacitor 102 absorbs energy rapidly but releases it quickly and absorbs a sharp voltage surge at the rise and fall of the output switching waveform, but there are cases where the suppression of high-frequency ringing is not sufficient.
  • the snubber capacitor 86 is connected in series with the snubber capacitor 86 to slow down energy absorption / release. [0901f02-formula02.gif0901f02-formula02.gif]
  • the harmonic component since the harmonic component is cut, the rise time and fall time of the output switching waveform become slow.
  • FIG. 13 shows a snubber circuit 92-2 in which a snubber diode 104 is connected in parallel to a snubber resistor 100 and a snubber capacitor 102 connected in series.
  • the snubber circuit 92-2 is connected to both ends of the high-side switching element 32 and the low-side switching element 40 connected in series, that is, to the H drain 36 and the L source 46 via the external electrodes 14-1 and 14-2. Yes.
  • the snubber diode 104 urges the energy stored in the snubber capacitor 102 to be released.
  • the snubber diode 104 may change the direction of the anode and the cathode to encourage the snubber capacitor 102 to accumulate energy. Further, it may be a snubber Zener diode.
  • a snubber circuit 92-2 in which a snubber diode 104 is connected in parallel to a snubber resistor 100 and a snubber capacitor 102 connected in series, is individually connected to the high-side switching element 32 and the low-side switching element 40.
  • the external electrodes are the external electrode 14-1 from the H drain 36 of the high side switching element 32, the external electrode 14-3 from the H source 38 of the high side switching element 32, and the external electrode 14-4 from the H drain 44 of the low side switching element 40.
  • the low-side switching element 40 is connected from the L source 46 to the external electrode 14-2.
  • One snubber circuit 92-2 is connected to the external electrode 14-1 and the external electrode 14-3, and another snubber circuit 92-2 is connected to the external electrode 14-4 and the external electrode 14-2. ing. In this way, the snubber circuit may be connected to individual switching elements.
  • the snubber circuit may have another circuit configuration, for example, the snubber circuit 92-1 shown in FIG. 12, or a combination of the snubber circuit 92-1 and the snubber circuit 92-2.
  • the external electrode 14-3 and the external electrode 14-4 may be a common electrode.
  • FIG. 15 a part of the electronic circuit component of the snubber circuit 92-2 is mounted on the printed board in the case, and the other electronic components are connected to the external electrodes 14-1 and 14-5. -2 is shown as an example.
  • the snubber diode 104 of the snubber circuit 92-2 is connected to the external electrodes 14-1 and 14-5, but the snubber resistor 100 or the snubber capacitor 102 is connected to the external electrodes 14-1 and 14-5. It may be configured. Of course, any two of the snubber resistor 100, the snubber capacitor 102, and the snubber diode 104 may be connected to the external electrodes 14-1 and 14-5.
  • FIG. 16 shows that one of the snubber circuits 92-2 individually connected to the high-side switching element 32 and the low-side switching element 40 is mounted on the printed board in the case, and the other electronic components are connected to the external electrode 14. -1 and 14-3 are externally mounted examples.
  • the snubber circuit 92-2 connected to the low-side switching element 40 is mounted internally, and the snubber circuit 92-2 connected to the high-side switching element 32 is mounted externally, but the snubber connected to the high-side switching element 32 is mounted.
  • the circuit 92-2 may be mounted internally, and the snubber circuit 92-2 connected to the low-side switching element 40 may be mounted externally.
  • Power MOSFETs used for switching elements in power modules can be classified into two types, vertical and horizontal, and the vertical type is particularly suitable for high breakdown voltage and low on-resistance.
  • the vertical type can be mounted in a multilayer structure to reduce the on-resistance and shorten the wiring, parasitic inductance can be suppressed.
  • a metal oxide semiconductor field effect transistor or an insulated gate bipolar transistor having a forward diode can be used, and an IGBT (Insulated Gate Bipolar Transistor) may be used.
  • the IGBT requires an FWD (Free Wheeling Diode) for commutating the load current, but can be used without increasing the number of parts by using an IGBT with a built-in FWD.
  • FWD Free Wheeling Diode
  • the IGBT has a structure in which a p + layer is added on the drain side of the power MOSFET, and is an element capable of lowering the on-resistance with a larger current than the power MOSFET.
  • GaN gallium nitride
  • GaN-based semiconductors are expected as materials for next-generation power semiconductor devices capable of high-voltage and high-speed switching.
  • a GaN-based semiconductor device has a wider band gap than Si (silicon), and can achieve higher breakdown voltage and lower loss than Si semiconductor devices.
  • a GaN-based transistor generally has a HEMT (High Electron Mobility Transistor) structure using a two-dimensional electron gas (2DEG) as a carrier (hereinafter, a GaN-HEMT structure switching element is abbreviated as GaN).
  • HEMT High Electron Mobility Transistor
  • 2DEG two-dimensional electron gas
  • SiC Silicon Carbide
  • the dielectric breakdown electric field strength is 10 times that of silicon and the band gap is 3 times that of silicon, and there are currently devices of the 1200V, 100A class.
  • the on-resistance is lowered to 10 m ⁇ ⁇ cm 2 which is the same area resistivity as that of silicon, a withstand voltage of 1600 V is obtained.
  • GaN is superior to SiC in terms of electron mobility and dielectric breakdown electric field strength, it is suitable for high power conversion capacity.
  • SiC has a thermal conductivity approximately three times higher than that of GaN, and is suitable for use at high temperatures.
  • gallium oxide gallium oxide Ga 2 O 3
  • the band gap of gallium oxide is 4.7 to 4.9, which is much higher than 3.3 to 3.4 of GaN and SiC, and can achieve low on-resistance. For this reason, a further highly efficient and high performance power device is possible.
  • the power module according to the present invention can use any of a switching element and a rectifying element which are elements made of GaN, SiC and gallium oxide.
  • GaN is suitable for low on-resistance and high-speed switching compared to Si devices, but it is normally-on (depletion-mode) operation, and is normally-off (enhancement-mode) operation from the viewpoint of fail-safe. Devices that can be used are expected in the future. Further, SiC has a problem that must be solved in terms of characteristics and reliability due to deterioration of oxide film reliability and channel mobility, but is a device expected in the future.
  • normally-on-type power devices operate normally-off type power devices, they can be driven and controlled as normally-off by cascode connection with normally-off type switching devices.
  • FIG. 17 shows an example of a packaged cascode connection element 110, showing a package bottom surface and an internal equivalent circuit.
  • the cascode connection includes a normally-on type first switching element 112 and a normally-off type.
  • the second switching element 114 The source of the first switching element 112 is connected to the drain of the second switching element 114, and the gate of the first switching element 112 is connected to the source of the second switching element 114.
  • a gate signal is applied to the gate of the second switching element 114, a current flows to the drain of the second switching element 114, and this current is converted into a source current of the first switching element 112.
  • This source current becomes the drain current of the first switching element 112.
  • the impedance between the drain of the first switching element 112 and the gate of the second switching element 114 is high, and the circuit configuration is excellent in frequency characteristics.
  • the drain electrode D of the first switching element 112, the gate electrode G of the second switching element 114, and the gate of the first switching element 112 and the second switching element 114 are formed on the bottom surface of the package.
  • FIG. 18 shows an example in which GaN and / or SiC is used for the cascade connection circuit.
  • GaN and / or SiC uses GaN and / or SiC for the first switching element 112 of the cascade connection element 110 shown in FIG.
  • FIG. 19 shows an example in which the cascade connection circuit is applied to a switching circuit.
  • a high-side switching element in which the switching element 112-1 made of GaN or SiC and the MOSFET 114-1 are cascade-connected, and a low-side side switching in which the switching element 112-2 and the MOSFET 114-2 each made of GaN or SiC are also cascade-connected.
  • the element is connected in series.
  • a normally-on type power element with high speed and high withstand voltage can be handled as a normally-off type power element, and can be applied to the power module of the present invention.
  • FIG. 20 is a circuit diagram of Example 1 of a synchronous rectification step-down DC / DC converter to which the present invention is applied.
  • the input voltage 52 is 395 V
  • the input capacitor 54 has two 47 ⁇ F electrolytic capacitors connected in parallel.
  • the switching circuit 30 has a high-side power MOSFET 80 and a low-side power MOSFET 82 connected in series, and a switching waveform from the control unit is input to the gate.
  • the inductance of the output inductor 58 is 24.9 ⁇ H, and the capacitance of the output capacitor 60 is 0.0022 ⁇ F.
  • the switching circuit 30 in which power MOSFETs are connected in series is used as the power module 20 of the present invention.
  • the power module 20 pad-shaped external electrodes 14-1 to 14-4 are provided on the bottom surface and connected to the switching circuit 30 by vias.
  • the noise removing capacitor 22 is an externally mounted component of the module, only two external electrodes are required, and only the external electrode 14-1 and the external electrode 14-2 are used. Since the capacitor 22 is an externally mounted component, a space for mounting the capacitor 22 on the circuit board is not required, and wiring to other electronic components can be shortened.
  • the avalanche diode shown in FIG. 11 or the snubber circuit shown in FIG. 12 and FIG. 13 may be mounted on the external electrode 14-1 and the external electrode 14-2, and design can be performed while measuring noise. A low noise switching power supply was obtained. (Example 2)
  • Example 2 individual snubber circuits for the high-side power MOSFET 80 and the low-side power MOSFET 82 were formed using the external electrodes 14-1 to 14-4 shown in FIG.
  • the snubber circuit 92-2 shown in FIG. 14 is mounted on the external electrodes 14-1 to 14-4.
  • the resistance and capacitor of the snubber circuit 92-2 could be designed while measuring noise, and a low noise switching power supply could be obtained.
  • FIG. 21 shows the measurement results of Example 1 and Example 2.
  • the voltage waveform at the location indicated by the arrow in FIG. 20 is measured with an FET probe, and the output voltage of the switching circuit is measured.
  • FIG. 21A is a voltage waveform when the capacitor capacity in the first embodiment and the capacitor capacity and resistance value of the snubber circuit in the second embodiment are set by the simulation means and mounted on the external electrode. The voltage waveform was the same in both Example 1 and Example 2.
  • FIG. 21 (B) is a voltage waveform showing the result of removing noise by adjusting the values of externally mounted electronic components while measuring noise.
  • Example 1 the capacitor capacity was adjusted while measuring noise, and in the snubber circuit in Example 2, the capacitor capacity and resistance value were adjusted while measuring noise. Surge voltage was removed and high frequency ringing was suppressed. This confirmed the effectiveness of the present invention.
  • switching power supplies provided with the power module of the present invention include switching power supplies using DC / DC converters and switching power supplies using AC / DC converters. Furthermore, a functional power module corresponding to the unit may be used.
  • FIG. 22 is a circuit example of a step-up type synchronous rectification DC / DC converter.
  • the synchronous rectification step-up DC / DC converter has a circuit configuration in which the input and output are reversed in the step-down synchronous rectification DC / DC converter shown in FIG.
  • the capacitor 22 connected to the switching circuit is applied as an externally mounted component.
  • This is a synchronous rectification step-up DC / DC converter circuit when the switching element is in cascode connection and GaN is used as the first switching element.
  • GaN, synchronous boost DC / DC converter circuit can cope with 1kV or more output voltage DC out.
  • FIG. 23 shows an example of a system equipped with a plurality of power modules.
  • Functional power modules are modules that employ many power semiconductors, such as diodes, thyristors, and MOSFETs, and that can achieve high efficiency with single-phase and three-phase bridges. It corresponds to a wide range of markets such as industrial equipment and automobile market.
  • the functional power module shown in FIG. 23 is a functional power module for automobiles, and includes a starter generator, an inverter rectifier, a DC booster, a buck-boost unit, an inverter output unit, and a bidirectional inverter unit.
  • the power module 20-4 using the three-phase inverter circuit shown in FIG. 4 for the inverter rectifier and the power module 20-4 using the switching circuit shown in FIG. Module is applicable.

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Abstract

The purpose of the present invention is to provide a power module configuration for suppressing the occurrence of noise. The outer peripheral surface of a power module in which mounted electric components are packaged is provided with external electrodes electrically connected to the electric components. In comparison with the case of two-dimensional mounting inside the power module, this structure not only makes it possible for the electric components to be mounted three-dimensionally, thereby shortening the wiring, but also allows the electric components electrically connected to the external electrodes of the electric components to form a switching circuit. A protection circuit and other circuits are mounted at the external electrodes and an electronic circuit mounting region within the module is eliminated, thereby reducing a parasitic inductance and a parasitic capacitance. It is also possible to select elements for a snubber circuit while measuring noise generated when the power module is mounted, so that the degree of freedom of a design is improved and the effect of suppressing noise, that is, surge voltage and high-frequency ringing is improved.

Description

パワーモジュール及びスイッチング電源Power module and switching power supply
 本発明はパワーモジュール及びスイッチング電源に関する。 The present invention relates to a power module and a switching power supply.
 最近のパワーエレクトロニクスは、パワーデバイス技術の開発により高速スイッチング化が進んでいる。パワーMOSFET(酸化物半導体電界効果トランジスタ)、IGBT(絶縁ゲートバイポーラトランジスタ)、さらには次世代デバイスとして注目されているGaN(ガリウム・ナイトライド)やSiC(シリコン・カーバイド)等の高速パワーデバイスを適用したハードスイッチングをベースとした高周波スイッチング回路では、スイッチング周波数の上昇に伴い、スイッチング損失の増大や回路配線の寄生インダクタンスによる電磁ノイズの増加など、従来の技術では十分な対応ができず、解決すべき問題が多く生じている。スイッチングの高速化は、例えばスイッチングのターンオフタイミングで、スイッチング素子の出力スイッチング波形に対して大きなサージ電圧が印加されストレスをもたらす場合があり、更には、寄生インダクタンスや寄生コンデンサ等の条件によっては、自励発振して制御不能となる場合があった。 Recent power electronics has been switching to high speed by developing power device technology. Power MOSFET (oxide semiconductor field effect transistor), IGBT (insulated gate bipolar transistor), and high-speed power devices such as GaN (gallium nitride) and SiC (silicon carbide), which are attracting attention as next-generation devices, are applied. In conventional high-frequency switching circuits based on hard switching, with the increase in switching frequency, conventional technologies cannot cope with such problems as increased switching loss and increased electromagnetic noise due to parasitic inductance of circuit wiring. There are many problems. For example, high switching speed may cause stress by applying a large surge voltage to the output switching waveform of the switching element at the turn-off timing of the switching element. Furthermore, depending on conditions such as parasitic inductance and parasitic capacitor, the switching speed may increase. There was a case where control was impossible due to excitation oscillation.
 これに対して、特許文献1には、同一基板に形成された配線に、バンプ等を用いて、スイッチング素子、スナバコンデンサ、スナバ抵抗及びスナバコンデンサを実装してモジュール化し、サージ電圧を低減する方法が開示されている。特許文献2には半導体チップ、上側および下側放熱板、各種端子や配線を一体化した多層配線バスバー、制御端子、素子中継電極及びプレートなどを備えた構成とし、スイッチング素子をモジュール内に多層配置して寄生インダクタンスを減らす方法が開示されている。 On the other hand, Patent Document 1 discloses a method for reducing a surge voltage by mounting a switching element, a snubber capacitor, a snubber resistor, and a snubber capacitor on a wiring formed on the same substrate by using a bump, etc. Is disclosed. Patent Document 2 includes a semiconductor chip, upper and lower heat sinks, a multilayer wiring bus bar in which various terminals and wires are integrated, a control terminal, an element relay electrode, a plate, and the like, and switching elements are arranged in a multilayer in the module. Thus, a method for reducing parasitic inductance is disclosed.
 モジュール内での多層構造による寄生インダクタンス低減については、特許文献3にも開示されている。高電位側のスイッチング素子および低電位側のスイッチング素子が多層基板の同一層に埋め込まれ、これらの形成された層が互いに絶縁されて配置されている。高電位側のスイッチング素子および低電位側のスイッチング素子は、いずれも縦型のデバイスである。これらスイッチング素子の上面部には配線層が設けられており、ビア導体を介して多層基板の表面にスナバ回路が接続されている。スナバ回路は、配線層間を最短で結ぶ電気経路に平行に走るように配置されている。また、配線層とスナバ回路との接続手段であるビア導体の長さは、これらビア導体および配線層接続点とビア導体および配線層の接続点との間隔よりも十分に短いものとなっている。 The reduction of parasitic inductance due to the multilayer structure in the module is also disclosed in Patent Document 3. The high-potential side switching element and the low-potential side switching element are embedded in the same layer of the multilayer substrate, and these formed layers are arranged to be insulated from each other. The high-potential side switching element and the low-potential side switching element are both vertical devices. A wiring layer is provided on the upper surface of these switching elements, and a snubber circuit is connected to the surface of the multilayer substrate via via conductors. The snubber circuit is arranged so as to run parallel to the electrical path connecting the wiring layers in the shortest distance. In addition, the length of the via conductor, which is a connection means between the wiring layer and the snubber circuit, is sufficiently shorter than the distance between the via conductor and wiring layer connection point and the via conductor and wiring layer connection point. .
 特許文献4は、電源装置の主回路の寄生インダクタンスを低減することのできる回路構成技術を開示している。第1半導体チップ及び第2半導体チップの電界効果トランジスタをnチャネル型の縦型電界効果トランジスタで形成し、第1半導体チップのソース電極が配置された面と、第2半導体チップのドレイン電極が配置された面を同一のチップ搭載部に搭載して互いに電気的に接続し、第1半導体チップのドレイン電極は入力電源供給用の外部端子に接続された第1リード板を有し、第2半導体チップのソース電極は基準電位供給用の外部端子に接続された第2リード板を有している。第1リード板と第2リード板との間に電気的に接続されたコンデンサを備え、コンデンサは、一対の電極の一方が第1リード板に接合され、一対の電極の他方が第2リード板に接合されてパッケージ表面に実装されている。 Patent Document 4 discloses a circuit configuration technique capable of reducing the parasitic inductance of the main circuit of the power supply device. The field effect transistors of the first semiconductor chip and the second semiconductor chip are formed of n-channel vertical field effect transistors, and the surface on which the source electrode of the first semiconductor chip is disposed and the drain electrode of the second semiconductor chip are disposed. Mounted on the same chip mounting portion and electrically connected to each other, the drain electrode of the first semiconductor chip has a first lead plate connected to an external terminal for supplying input power, and the second semiconductor The source electrode of the chip has a second lead plate connected to an external terminal for supplying a reference potential. A capacitor is provided that is electrically connected between the first lead plate and the second lead plate. The capacitor has one of the pair of electrodes joined to the first lead plate, and the other of the pair of electrodes is the second lead plate. And is mounted on the surface of the package.
特開2012-135065号公報JP 2012-1335065 A 特開2015-211524号公報JP 2015-2111524 A 特開2012-115128号公報JP 2012-115128 A 特開2008-010851号公報JP 2008-010851 A
 しかしながら、スイッチング電源では、SiCやGaNといった次世代デバイスを搭載した、より高電圧、大電流で高速スイッチングが要求されており、従来構造ではサージ発生や自励発振を十分に抑制することが困難であった。また、同一平面に部品が実装されているため、配線が長くなり、寄生インダクタンスが大きくなる課題があった。 However, switching power supplies require next-generation devices such as SiC and GaN to perform high-speed switching at higher voltages and larger currents, and it is difficult to sufficiently suppress surge generation and self-excited oscillation with the conventional structure. there were. Further, since the components are mounted on the same plane, there is a problem that the wiring becomes long and the parasitic inductance increases.
 ディスクリート部品で構成する従来のスイッチング電源では、配線長を短くすることができず、寄生インダクタンス等に起因してスイッチング動作が不安定になるといった課題があった。そのため、パワーモジュールによって、可能な限り寄生インダクタンス等を低減して動作を安定させるといった対策がなされている。しかしながら、スイッチング動作は入出力条件や設計条件によって異なるため、内部に設けた電子部品の定数によっては、スイッチング動作が不安定になることがあり、入出力条件や設計条件が制限されてしまうといった課題があった The conventional switching power supply composed of discrete components has a problem that the wiring length cannot be shortened and the switching operation becomes unstable due to parasitic inductance or the like. Therefore, the power module takes measures such as reducing parasitic inductance as much as possible to stabilize the operation. However, since the switching operation varies depending on the input / output conditions and the design conditions, depending on the constants of the electronic components provided inside, the switching operation may become unstable, and the input / output conditions and the design conditions are limited. was there
 例えば、ノイズ対策としてモジュール内部にスナバ回路を設けているが、回路設計する場合にスナバコンデンサやスナバ抵抗等の容量値や抵抗値は固定されてしまう。このため、実装した場合に、ノイズに対応した選択の自由が妨げられ、モジュールの信頼性が低下するといった課題があった。 For example, a snubber circuit is provided inside the module as a measure against noise, but the capacitance value and resistance value such as a snubber capacitor and snubber resistance are fixed when designing the circuit. For this reason, when mounted, there is a problem that freedom of selection corresponding to noise is hindered and the reliability of the module is lowered.
 モジュール内部にスナバ回路を設ける構造は、スナバ回路を搭載する領域とスナバ回路に接続する配線が必要となり、他の部品の配線距離を長くして、より寄生インダクタンスを発生させたり、スナバ回路への配線にも寄生インダクタンスを発生させたりする課題があった。 The structure in which the snubber circuit is provided inside the module requires the area where the snubber circuit is mounted and the wiring to connect to the snubber circuit. The wiring distance of other parts is increased to generate more parasitic inductance, and to the snubber circuit. There was also a problem of generating parasitic inductance in the wiring.
 また、モジュール外部のプリント基板上にスナバ回路を設けることも考えられるが、スイッチング素子からプリント基板上のスナバ回路までの配線に寄生インダクタンスが発生し、サージ電圧増加や動作の不安定性に繋がるといった課題があった。 In addition, it is conceivable to provide a snubber circuit on the printed circuit board outside the module, but parasitic inductance occurs in the wiring from the switching element to the snubber circuit on the printed circuit board, leading to an increase in surge voltage and unstable operation. was there.
 本発明は、これらの課題を解決し、ノイズの発生を抑止するパワーモジュール構成を提供することを目的としている。 An object of the present invention is to provide a power module configuration that solves these problems and suppresses the generation of noise.
 (1)本発明によるパワーモジュールは、少なくともスイッチング素子又は整流素子を含むケース内搭載電子部品と、ケース内搭載電子部品が樹脂封止されたモールドケースと、モールドケースの外表面に露出した2以上の外部電極と、ケース内搭載電子部品と外部電極を電気的に接続する導電部材又はビアと、を備えている。 (1) The power module according to the present invention includes an in-case electronic component including at least a switching element or a rectifying element, a mold case in which the in-case electronic component is resin-sealed, and two or more exposed on the outer surface of the mold case External electrodes and conductive members or vias that electrically connect the in-case electronic components and the external electrodes.
 ケース内搭載電子部品による回路は完成された回路ではない場合、モールドケースの外表面に露出した2以上の外部電極に、モールドケース外部から設計条件に適合させた電子部品を搭載することによって最終的に目的の機能を発揮する回路となる。 If the circuit by the electronic components mounted in the case is not a completed circuit, the electronic components adapted to the design conditions from the outside of the mold case are mounted on two or more external electrodes exposed on the outer surface of the mold case. It becomes a circuit that demonstrates the intended function.
 (2)本発明によるパワーモジュールは、少なくともスイッチング素子又は整流素子を含むケース内搭載電子部品と、ケース内搭載電子部品が樹脂封止されたモールドケースと、モールドケースの外表面に露出した2以上の外部電極と、ケース内搭載電子部品と外部電極を電気的に接続する導電部材又はビアと、外部電極に電気的に接続された外部搭載電子部品と、を備えている。 (2) The power module according to the present invention includes an in-case electronic component including at least a switching element or a rectifying element, a mold case in which the in-case electronic component is resin-sealed, and two or more exposed on the outer surface of the mold case External electrodes, conductive members or vias that electrically connect the in-case electronic components and the external electrodes, and external electronic components that are electrically connected to the external electrodes.
 ケース内搭載電子部品による回路と、モールドケースの外表面に露出した2以上の外部電極に、モールドケース外部から設計条件に適合させた外部搭載電子部品を搭載することによって最終的に目的の機能を発揮する回路となる。 By mounting externally mounted electronic components that meet the design conditions from the outside of the mold case on the circuit of the electronic components mounted in the case and two or more external electrodes exposed on the outer surface of the mold case, the final function is achieved. It becomes a circuit to demonstrate.
 (3)外部搭載電子部品は、少なくともコンデンサを含んでいてもよい。 (3) The externally mounted electronic component may include at least a capacitor.
 (4)外部搭載電子部品は、スイッチング波形の寄生成分に起因するサージを吸収する保護回路が接続されていてもよい。 (4) The externally mounted electronic component may be connected to a protection circuit that absorbs a surge caused by a parasitic component of the switching waveform.
 (5)保護回路は、少なくとも抵抗、ダイオード又はコンデンサのいずれか1つを含むスナバ回路であってもよい。 (5) The protection circuit may be a snubber circuit including at least one of a resistor, a diode, and a capacitor.
 (6)外部搭載電子部品は、少なくとも半導体素子を含んでいてもよい。 (6) The externally mounted electronic component may include at least a semiconductor element.
 (7)半導体素子は、サージ吸収用のアバランシェサージダイオードを含んでいてもよい。 (7) The semiconductor element may include an avalanche surge diode for absorbing surge.
 (8)スイッチング素子又は整流素子は、ガリウム・ナイトライド、ガリウム・オキサイド又はシリコン・カーバイドから成る素子を含んでいてもよい。 (8) The switching element or the rectifying element may include an element made of gallium nitride, gallium oxide, or silicon carbide.
 (9)スイッチング素子は、ノーマリーオン型半導体とノーマリーオフ型半導体とがカスコード接続されていてもよい。 (9) In the switching element, a normally-on type semiconductor and a normally-off type semiconductor may be cascode-connected.
 (10)本発明によるパワーモジュールを使用してスイッチング電源とすることができる。 (10) The power module according to the present invention can be used as a switching power supply.
 (1)本発明によるパワーモジュールは、少なくともスイッチング素子又は整流素子を含むケース内搭載電子部品と、ケース内搭載電子部品が樹脂封止されたモールドケースと、モールドケースの外表面に露出した2以上の外部電極と、ケース内搭載電子部品と外部電極を電気的に接続する導電部材又はビアと、を備えている。ケース内搭載電子部品による回路は完成された回路ではない場合、モールドケースの外表面に露出した2以上の外部電極に、モールドケース外部から設計条件に適合させた電子部品を搭載することによって最終的に目的の機能を発揮する回路となる。 (1) The power module according to the present invention includes an in-case electronic component including at least a switching element or a rectifying element, a mold case in which the in-case electronic component is resin-sealed, and two or more exposed on the outer surface of the mold case External electrodes and conductive members or vias that electrically connect the in-case electronic components and the external electrodes. If the circuit by the electronic components mounted in the case is not a completed circuit, the electronic components adapted to the design conditions from the outside of the mold case are mounted on two or more external electrodes exposed on the outer surface of the mold case. It becomes a circuit that demonstrates the intended function.
 このため、ケース内搭載電子部品による回路には、モールドケース外部から設計条件に適合させた電子部品を搭載するスペースが不要となり、高密度に電子部品が配置できる。これにより、配線パターンを短くすることができ、寄生インダクタンスを最小限とする構造となる。2以上の複数の外部電極を形成することにより、各種回路に対応でき、入出力条件や設計条件に幅広く適合できるため、制限がされずに、安定的なスイッチング動作を可能とするパワーモジュール及びスイッチング電源を提供することができる。幅広く適用可能であり、例えば3相インバータモジュールにも適用可能である。 For this reason, the circuit using the electronic components mounted in the case does not require a space for mounting electronic components adapted to the design conditions from the outside of the mold case, and the electronic components can be arranged at high density. As a result, the wiring pattern can be shortened and the parasitic inductance is minimized. By forming two or more external electrodes, it can be used for various circuits and can be widely adapted to input / output conditions and design conditions, so power modules and switching that enable stable switching operation without restrictions Power can be provided. The present invention can be widely applied. For example, it can be applied to a three-phase inverter module.
 (2)本発明によるパワーモジュールは、少なくともスイッチング素子又は整流素子を含むケース内搭載電子部品と、ケース内搭載電子部品が樹脂封止されたモールドケースと、モールドケースの外表面に露出した2以上の外部電極と、ケース内搭載電子部品と外部電極を電気的に接続する導電部材又はビアと、外部電極に電気的に接続された外部搭載電子部品と、を備えている。ケース内搭載電子部品による回路と、モールドケースの外表面に露出した2以上の外部電極に、モールドケース外部から設計条件に適合させた外部搭載電子部品によって最終的に目的の機能を発揮する回路となる。 (2) The power module according to the present invention includes an in-case electronic component including at least a switching element or a rectifying element, a mold case in which the in-case electronic component is resin-sealed, and two or more exposed on the outer surface of the mold case External electrodes, conductive members or vias that electrically connect the in-case electronic components and the external electrodes, and external electronic components that are electrically connected to the external electrodes. A circuit with an electronic component mounted in the case, and a circuit that finally exerts the intended function by the external mounted electronic component adapted to the design conditions from the outside of the mold case to two or more external electrodes exposed on the outer surface of the mold case Become.
 このため、ケース内搭載電子部品による回路には、モールドケース外部から設計条件に適合させた電子部品を搭載するスペースが不要となり、高密度に電子部品が配置でき、配線パターンを短くすることができる。これにより、寄生インダクタンスを最小限とする構造となる。2以上の外部電極を形成することにより、各種回路に対応でき、入出力条件や設計条件に制限されず幅広く適合できるため、安定的なスイッチング動作を可能とするパワーモジュール及びスイッチング電源を提供することができる。また、外部電極を介して搭載される電子部品を任意に選択でき、設計の自由度が向上する。 For this reason, a circuit using electronic components mounted in the case does not require a space for mounting electronic components adapted to the design conditions from the outside of the mold case, electronic components can be arranged at high density, and the wiring pattern can be shortened. . As a result, the parasitic inductance is minimized. Providing a power module and a switching power supply capable of stable switching operation by forming two or more external electrodes, which can be applied to various circuits and can be widely adapted without being limited by input / output conditions and design conditions. Can do. In addition, an electronic component mounted via the external electrode can be arbitrarily selected, and the degree of freedom in design is improved.
 (3)外部電極に少なくともコンデンサが接続されているため、ケース内搭載部品が減少し、高密度に実装可能となるため配線を短くすることができ、寄生インダクタンスを最小限とする構造となる。さらにコンデンサによるスナバ効果によって、入出力条件や設計条件に制限されずに、安定的なスイッチング動作を可能とするパワーモジュール及びスイッチング電源を提供することができる。 (3) Since at least a capacitor is connected to the external electrode, the number of components mounted in the case is reduced, and high-density mounting is possible, so that the wiring can be shortened and the parasitic inductance is minimized. Furthermore, a power module and a switching power supply that enable a stable switching operation without being limited by input / output conditions and design conditions due to the snubber effect by the capacitor can be provided.
 (4)外部搭載電子部品は、スイッチング波形の寄生成分に起因するサージを吸収する保護回路が接続されていてもよい。外部搭載部品をスイッチング波形の寄生成分に起因するサージを吸収する保護回路とすることにより、スイッチング素子の近傍に保護回路を形成でき、配線パターンの短縮化が可能となる。これにより、パワーモジュールと外部電極に接続される電子部品との間の寄生インダクタンスを最小限とする構造となり、入出力条件や設計条件に制限されずに、安定的なスイッチング動作を可能とするパワーモジュール及びスイッチング電源を提供することができる。 (4) The externally mounted electronic component may be connected to a protection circuit that absorbs a surge caused by a parasitic component of the switching waveform. By using an externally mounted component as a protection circuit that absorbs surges caused by parasitic components of the switching waveform, the protection circuit can be formed in the vicinity of the switching element, and the wiring pattern can be shortened. This structure minimizes the parasitic inductance between the power module and the electronic components connected to the external electrodes, and enables a stable switching operation without being restricted by input / output conditions or design conditions. Modules and switching power supplies can be provided.
 (5)保護回路は、少なくとも抵抗、ダイオード、前記コンデンサのいずれか1つを含むスナバ回路であってもよい。例えばコンデンサとダイオードとを有する第1スナバ回路、コンデンサとダイオードと抵抗を有する第2スナバ回路とをサージ吸収保護回路として接続する。これにより、パワーモジュールと外部電極に接続される電子部品との間の配線パターンの短縮化が可能となる。このため、寄生インダクタンスを最小限とする構造となり、入出力条件や設計条件に制限されずに、安定的なスイッチング動作を可能とするパワーモジュール及びスイッチング電源を提供することができる。 (5) The protection circuit may be a snubber circuit including at least one of a resistor, a diode, and the capacitor. For example, a first snubber circuit having a capacitor and a diode, and a second snubber circuit having a capacitor, a diode, and a resistor are connected as a surge absorption protection circuit. As a result, the wiring pattern between the power module and the electronic component connected to the external electrode can be shortened. For this reason, it becomes a structure which minimizes a parasitic inductance, and can provide the power module and switching power supply which enable stable switching operation | movement, without being restrict | limited to input-output conditions or design conditions.
 (6)外部搭載電子部品を少なくとも半導体素子として、スイッチング素子に保護回路をけいせいする含んでいてもよい。半導体素子は、ダイオード、サイリスタ、サーバアブソーバやパワーツェナー等である。これにより、配線パターンの短縮化が可能で、寄生インダクタンスを最小限とする構造となり、入出力条件や設計条件に制限されずに、安定的なスイッチング動作を可能とするパワーモジュール及びスイッチング電源を提供することができる。 (6) An externally mounted electronic component may be included as at least a semiconductor element, and a protective circuit may be included in the switching element. The semiconductor element is a diode, a thyristor, a server absorber, a power Zener, or the like. As a result, the wiring pattern can be shortened and the parasitic inductance is minimized, providing a power module and a switching power supply that enable stable switching operation without being restricted by input / output conditions or design conditions. can do.
 (7)半導体素子は、サージ吸収用のアバランシェサージダイオードを含んでいる。保護回路は、アバランシェサージブレークダウンダイオードを含むサージ吸収保護回路を接続して構成する。これにより、サージ吸収機能を有するモジュールを構成することができ、更に、パワーモジュールと外部電極に接続される電子部品との間の配線パターンの短縮化が可能となる。このため、寄生インダクタンスを最小限とする構造となり、入出力条件や設計条件に制限されずに、安定的なスイッチング動作を可能とするパワーモジュール及びスイッチング電源を提供することができる。 (7) The semiconductor element includes an avalanche surge diode for surge absorption. The protection circuit is configured by connecting a surge absorption protection circuit including an avalanche surge breakdown diode. As a result, a module having a surge absorbing function can be configured, and further, the wiring pattern between the power module and the electronic component connected to the external electrode can be shortened. For this reason, it becomes a structure which minimizes a parasitic inductance, and can provide the power module and switching power supply which enable stable switching operation | movement, without being restrict | limited to input-output conditions or design conditions.
 (8)ケース内搭載電子部品は、少なくともスイッチング素子又は整流素子を含み。スイッチング素子又は整流素子はガリウム・ナイトライド、ガリウム・オキサイド又はシリコン・カーバイドから成る素子を含んでいてもよい。スイッチング素子又は整流素子は、ガリウム・ナイトライド、ガリウム・オキサイド又はシリコン・カーバイドを含む素子であるため、スイッチング速度を高めて高効率化が可能となるだけでなく、高電圧に対応でき、さらに安定的なスイッチング動作を可能とするパワーモジュール及びスイッチング電源を提供することができる。 (8) The electronic components mounted in the case include at least a switching element or a rectifying element. The switching element or rectifying element may include an element made of gallium nitride, gallium oxide, or silicon carbide. Switching elements or rectifying elements are elements that contain gallium nitride, gallium oxide, or silicon carbide. Therefore, not only can the switching speed be increased to achieve higher efficiency, but also higher voltage can be accommodated, and more stable. It is possible to provide a power module and a switching power supply that enable efficient switching operation.
 (9)スイッチング素子は、ノーマリーオン型半導体とノーマリーオフ型半導体とがカスコード接続されていてもよい。例えばGaNやSiCは、高速高耐圧といった長所がある反面、ノーマリーオン型で構成される場合もあるため、フェイルセーフの観点からノーマリ―オフ型の動作が求められている。この場合の対策としては、例えばノーマリ―オフ型のMOSFETをカスコ―ド接続する技術でノーマリ―オフ型を実現することができる。このため低ノイズで安定的なスイッチング動作を可能とするパワーモジュール及びスイッチング電源を提供することができる。 (9) In the switching element, a normally-on type semiconductor and a normally-off type semiconductor may be cascode-connected. For example, while GaN and SiC have advantages such as high speed and high withstand voltage, they may be configured as normally-on type, so normally-off type operation is required from the viewpoint of fail-safe. As a countermeasure in this case, for example, a normally-off type can be realized by a technique of cascading normally-off MOSFETs. Therefore, it is possible to provide a power module and a switching power supply that enable a stable switching operation with low noise.
 (10)本発明によりパワーモジュールを使用してスイッチング電源とすることができる。寄生インダクタンスを最小とする構造になり、安定的なスイッチング動作を可能とするスイッチング電源を提供することができる。
(10) According to the present invention, the power module can be used as a switching power supply. It is possible to provide a switching power supply that has a structure in which the parasitic inductance is minimized and enables a stable switching operation.
本発明によるパワーモジュールの外観図である。It is an external view of the power module by this invention. 本発明のパワーモジュールに外部搭載電子部品の一例としてコンデンサを搭載した外部電子部品搭載パワーモジュールの外観図である。It is an external view of the external electronic component mounting power module which mounted the capacitor | condenser as an example of the external mounting electronic component in the power module of this invention. パワーモジュール内部のスイッチング回路とコンデンサを外部電極に搭載した場合の電気回路例を説明する図である。It is a figure explaining the example of an electric circuit at the time of mounting the switching circuit and capacitor | condenser inside a power module on an external electrode. パワーモジュール内部のスイッチング回路を3個搭載して3相インバータを構成した例を示す図である。It is a figure which shows the example which mounted the three switching circuits inside a power module, and comprised the 3-phase inverter. スイッチング素子及び整流素子からなるモジュール例の接続図である。It is a connection diagram of a module example including a switching element and a rectifying element. 同期整流式降圧DC/DCコンバータの基本回路を示す図である。It is a figure which shows the basic circuit of a synchronous rectification type | mold step-down DC / DC converter. 同期整流式降圧DC/DCコンバータの寄生インダクタンスと寄生容量を考慮した等価回路を示す図である。It is a figure which shows the equivalent circuit which considered the parasitic inductance and parasitic capacitance of a synchronous rectification type | mold step-down DC / DC converter. DC/DCコンバータに使用されているスイッチング回路、ゲートドライブ回路と保護回路のブロック図である。It is a block diagram of the switching circuit, the gate drive circuit, and protection circuit which are used for the DC / DC converter. デッドタイムを説明する図である。It is a figure explaining dead time. スナバ回路の配線に発生する寄生インダクタを考慮した等価電気回路を示した図である。It is the figure which showed the equivalent electric circuit which considered the parasitic inductor which generate | occur | produces in the wiring of a snubber circuit. 保護回路にアバランシェダイオードを使用した例を説明する図である。It is a figure explaining the example which used the avalanche diode for the protection circuit. 保護回路にスナバ抵抗とスナバコンデンサを使用した例を説明する図である。It is a figure explaining the example which used the snubber resistance and the snubber capacitor for the protection circuit. 保護回路にスナバ抵抗とスナバコンデンサを使用し、さらにスナバダイオードをスナバ抵抗と並列に接続した例を説明する図である。It is a figure explaining the example which used the snubber resistor and the snubber capacitor for the protection circuit, and connected the snubber diode in parallel with the snubber resistor. ハイサイドスイッチング素子とローサイドスイッチング素子に、それぞれ保護回路を設けた例を説明する図である。It is a figure explaining the example which provided the protection circuit in the high side switching element and the low side switching element, respectively. 保護回路にスナバ抵抗、スナバコンデンサとスナバダイオードを使用しているが、スナバ抵抗とスナバコンデンサをモジュール内部に搭載し、スナバダイオードを外部電極に接続した例を説明する図である。FIG. 5 is a diagram for explaining an example in which a snubber resistor, a snubber capacitor and a snubber diode are used in the protection circuit, and the snubber resistor and the snubber capacitor are mounted inside the module and the snubber diode is connected to an external electrode. ハイサイドスイッチング素子とローサイドスイッチング素子に、それぞれ保護回路を設け、ローサイドスイッチング素子の保護回路をモジュール内部に搭載し、ハイサイドスイッチング素子の保護回路を外部電極に接続した例を説明する図である。It is a figure explaining the example which provided the protection circuit in each of the high side switching element and the low side switching element, mounted the protection circuit of the low side switching element in the inside of a module, and connected the protection circuit of the high side switching element to the external electrode. カスコ―ド接続素子の一例を示した図である。It is the figure which showed an example of the cascade connection element. カスコ―ド接続素子のスイッチング回路にGaN又はSiCを使用した例を説明する図である。It is a figure explaining the example which uses GaN or SiC for the switching circuit of a cascade connection element. カスコ―ド接続回路をスイッチング回路に適用した例を示す図である。It is a figure which shows the example which applied the cascade connection circuit to the switching circuit. 本発明を適用した同期整流式DC/DCコンバータの実施例を説明する図である。It is a figure explaining the Example of the synchronous rectification type DC / DC converter to which this invention is applied. 実施例の測定結果を示す図である。It is a figure which shows the measurement result of an Example. 昇圧型の同期整流式DC/DCコンバータの回路例を示す図である。It is a figure which shows the circuit example of a step-up type synchronous rectification type DC / DC converter. 実施形態に係る機能パワーモジュールの例を示す図である。It is a figure which shows the example of the functional power module which concerns on embodiment.
 以下、本発明の実施形態について図に基づいて説明する。なお、以下の各実施形態相互において、互いに同一もしくは均等である部分には、同一符号を付して説明を行う。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.
 本発明によるパワーモジュールは、少なくともスイッチング素子又は整流素子を含むケース内搭載電子部品と、ケース内搭載電子部品が樹脂封止されたモールドケースと、モールドケースの外表面に露出した2以上の外部電極と、ケース内搭載電子部品と外部電極を電気的に接続する導電部材又はビアと、を備えている。 A power module according to the present invention includes an in-case electronic component including at least a switching element or a rectifying element, a mold case in which the in-case electronic component is resin-sealed, and two or more external electrodes exposed on the outer surface of the mold case And a conductive member or via for electrically connecting the in-case mounted electronic component and the external electrode.
 図1は、本発明によるパワーモジュール10の底面(裏面)に外部電極14-1及び外部電極14―2を設けた構造を示している。外部電極14-1及び外部電極14―2は、電気部品をはんだ付けして接続するため、パッド形状となっている。外部電極14-1及び外部電極14―2は、モールドケース12の内部に搭載されている電子部品と導電部材又はビアを介して接続されている。リード16は、パワーモジュール10をプリント板に挿入するためのピンであり、ハンダで固定される。パワーモジュール10の内部には、複数個のパワー半導体を組み合わせて集積化したパワー回路が搭載されており、外部電極14-1及び外部電極14―2には、パワー回路を構成する部品の一部が接続される。 FIG. 1 shows a structure in which an external electrode 14-1 and an external electrode 14-2 are provided on the bottom surface (back surface) of a power module 10 according to the present invention. The external electrode 14-1 and the external electrode 14-2 have a pad shape for soldering and connecting electrical components. The external electrode 14-1 and the external electrode 14-2 are connected to electronic components mounted inside the mold case 12 through conductive members or vias. The lead 16 is a pin for inserting the power module 10 into the printed board, and is fixed with solder. A power circuit in which a plurality of power semiconductors are combined and integrated is mounted inside the power module 10. The external electrode 14-1 and the external electrode 14-2 are part of the components constituting the power circuit. Is connected.
 図2は、本発明による外部電子部品搭載パワーモジュール20の外観図である。少なくともスイッチング素子又は整流素子を含むケース内搭載電子部品と、ケース内搭載電子部品が樹脂封止されたモールドケース12と、モールドケース12の外表面に露出した2以上の外部電極と、ケース内搭載電子部品と外部電極を電気的に接続する導電部材又はビアと、外部電極に電気的に接続された外部搭載電子部品(例えばコンデンサ)と、を備えている。(以下、外部電子部品搭載パワーモジュール20は、単にパワーモジュール20という。) FIG. 2 is an external view of a power module 20 equipped with an external electronic component according to the present invention. In-case electronic component including at least a switching element or a rectifying element, a mold case 12 in which the in-case electronic component is resin-sealed, two or more external electrodes exposed on the outer surface of the mold case 12, and in-case mounting A conductive member or via for electrically connecting the electronic component and the external electrode, and an externally mounted electronic component (for example, a capacitor) electrically connected to the external electrode are provided. (Hereinafter, the external electronic component-mounted power module 20 is simply referred to as the power module 20.)
 外部電極14-1及び外部電極14―2に、外部搭載電子部品であるコンデンサ22が接続されている。コンデンサ22は、スイッチング素子のノイズ、即ち、サージや高調波リンギングを抑制する。コンデンサ22は、容量に応じて複数搭載してもよいが、高さがが限られているため、1つのコンデンサ22では容量が大きく外形が大きい場合、リード16に高さ調整用のスペーサを取り付けてもよい。これにより、電子部品搭載用の高さが確保され、1つの電子部品で済ませることができる。 A capacitor 22 which is an externally mounted electronic component is connected to the external electrode 14-1 and the external electrode 14-2. The capacitor 22 suppresses noise of the switching element, that is, surge and harmonic ringing. A plurality of capacitors 22 may be mounted depending on the capacity. However, since the height is limited, when one capacitor 22 has a large capacity and a large external shape, a spacer for adjusting the height is attached to the lead 16. May be. Thereby, the height for electronic component mounting is ensured, and it can be completed with one electronic component.
 図3は、外部電極14-1、14―2が接続されているパワーモジュール20のモールドケース12内部に搭載されているパワー回路の一例を示している。図3では、2個のスイッチング素子を直列に接続したスイッチング回路30の例を示している。スイッチング素子は、例えばパワーMOSFET(Metal-Oxide-Semiconductor Feeld-Effect-Transistor)である。ハイサイドスイッチング素子32のHソース38とローサイドスイッチング素子40のLドレイン44が接続されている。 FIG. 3 shows an example of a power circuit mounted in the mold case 12 of the power module 20 to which the external electrodes 14-1 and 14-2 are connected. FIG. 3 shows an example of a switching circuit 30 in which two switching elements are connected in series. The switching element is, for example, a power MOSFET (Metal-Oxide-Semiconductor, Field-Effect-Transistor). The H source 38 of the high side switching element 32 and the L drain 44 of the low side switching element 40 are connected.
 スイッチング回路30は、ハイサイドスイッチング素子32とローサイドスイッチング素子40が直列に接続して形成され、直列接続されたハイサイドスイッチング素子32とローサイドスイッチング素子40の両端部、即ち、Hドレイン36とLソース46が、外部電極14-1、14―2に接続されている。外部電極14-1、14―2には、コンデンサ22が接続され、スイッチング時のノイズを低減している。コンデンサ22は、モールドケース12の外部からの接続であるため、設計条件に応じて任意の容量が選択可能である。 The switching circuit 30 is formed by connecting a high-side switching element 32 and a low-side switching element 40 in series, and both ends of the high-side switching element 32 and the low-side switching element 40 connected in series, that is, an H drain 36 and an L source. 46 is connected to the external electrodes 14-1 and 14-2. A capacitor 22 is connected to the external electrodes 14-1 and 14-2 to reduce noise during switching. Since the capacitor 22 is connected from the outside of the mold case 12, an arbitrary capacity can be selected according to the design conditions.
 ハイサイドスイッチング素子32のHゲート34とローサイドスイッチング素子40のLゲート42は、ゲートドライブ回路(図示せず)に接続され、交互にオン/オフを繰り返すように制御されている。ハイサイドスイッチング素子32とローサイドスイッチング素子40が交互にオン/オフするため、同期整流方式と呼ばれている。 The H gate 34 of the high side switching element 32 and the L gate 42 of the low side switching element 40 are connected to a gate drive circuit (not shown), and are controlled to be repeatedly turned on / off alternately. Since the high-side switching element 32 and the low-side switching element 40 are alternately turned on / off, this is called a synchronous rectification method.
 図4は、モールドケース12の内部に搭載されているパワー回路の他の例を示している。図4は、パワーモジュール20-1の内部にあるパワー回路が、3個のスイッチング回路30-1、30-2、30-3を並列に接続して搭載した3相インバータ回路である。三相インバータ回路は、直流電源から3相の電圧波形を生成し、例えば三相交流モータを駆動するパワー回路として使用される。三相インバータ回路にはコンデンサ22が並列接続されており、スイッチング時のリプルの低減やノイズの影響が抑制された電圧波形が形成される。 FIG. 4 shows another example of the power circuit mounted inside the mold case 12. FIG. 4 shows a three-phase inverter circuit in which a power circuit in the power module 20-1 is mounted by connecting three switching circuits 30-1, 30-2 and 30-3 in parallel. The three-phase inverter circuit generates a three-phase voltage waveform from a DC power supply, and is used as a power circuit for driving a three-phase AC motor, for example. A capacitor 22 is connected in parallel to the three-phase inverter circuit, and a voltage waveform is formed in which ripples are reduced during switching and the influence of noise is suppressed.
 モールドケース12の内部に搭載されているパワー回路の例として、スイッチング素子が直列に接続されているスイッチング回路30と三相インバータ回路を示したが、この例に限られることはなく、スイッチング素子と整流素子を使用したスイッチング回路であってもよい。 As an example of the power circuit mounted inside the mold case 12, the switching circuit 30 and the three-phase inverter circuit in which the switching elements are connected in series have been shown. However, the present invention is not limited to this example. A switching circuit using a rectifying element may be used.
 図5は、スイッチング素子と整流素子を用いたスイッチング回路の例を示している。図5(A)は、図3に示したスイッチング回路30において、ローサイドスイッチング素子40を整流素子であるスイッチングダイオード48に置き換えたスイッチング回路30-4である。図5(B)は、図3に示したスイッチング回路30において、ハイサイドスイッチング素子32を整流素子であるスイッチングダイオード48に置き換えたスイッチング回路30-5である。スイッチングダイオード48は、リカバリ電流が少なく、順方向電圧が低く、SiC等のショットキーダイオードを使用すると、好適な場合もある。 FIG. 5 shows an example of a switching circuit using a switching element and a rectifying element. FIG. 5A shows a switching circuit 30-4 in which the low-side switching element 40 is replaced with a switching diode 48 that is a rectifying element in the switching circuit 30 shown in FIG. FIG. 5B shows a switching circuit 30-5 in which the high-side switching element 32 in the switching circuit 30 shown in FIG. 3 is replaced with a switching diode 48 that is a rectifying element. The switching diode 48 has a low recovery current and a low forward voltage, and it may be preferable to use a Schottky diode such as SiC.
 スイッチング素子と整流素子を用いたスイッチング回路は、同期整流方式に対して、非同期整流方式と呼ばれている。図5(A)に示したスイッチング回路30-4は、ハイサイドスイッチング素子32がオンのとき、スイッチングダイオード48には電流が流れず、ハイサイドスイッチング素子32がオフのとき、スイッチングダイオード48には順方向電流が流れる。非同期整流方式は、同期整流方式に比べて効率が劣り、出力電圧をアクティブに制御できず、負荷電流が減少すると高周波リンギングが発生することもあるが、スイッチング素子が1つであるため、電源回路に適用する場合は、制御回路が簡単に構成できる特徴がある。 A switching circuit using a switching element and a rectifying element is called an asynchronous rectifying system as opposed to a synchronous rectifying system. In the switching circuit 30-4 shown in FIG. 5A, no current flows through the switching diode 48 when the high-side switching element 32 is on, and no current flows through the switching diode 48 when the high-side switching element 32 is off. A forward current flows. The asynchronous rectification method is inferior to the synchronous rectification method, and the output voltage cannot be actively controlled. When the load current is reduced, high-frequency ringing may occur, but there is only one switching element. When applied to the control circuit, the control circuit can be easily configured.
 図5(A)に示したスイッチング回路30-4は降圧DCコンバータのスイッチング回路として使用され、図5(B)に示したスイッチング回路30-5は昇圧DCコンバータのスイッチング回路として使用される。降圧DCコンバータと昇圧DCコンバータは、同期整流方式では基本的な回路構成は同じで、一方を入力とし他方を出力として兼用でき、出力とした方から負帰還制御を行い各々のスイッチのタイミングを制御し、逆方向に電流を流して制御しているという部分が異なっているだけである。これに対して、非同期整流方式では、スイッチングダイオード48が順方向電流しか流れないために、降圧DCコンバータと昇圧DCコンバータは別の回路となる。 The switching circuit 30-4 shown in FIG. 5A is used as a switching circuit for a step-down DC converter, and the switching circuit 30-5 shown in FIG. 5B is used as a switching circuit for a step-up DC converter. The basic circuit configuration of the step-down DC converter and the step-up DC converter is the same in the synchronous rectification method. One of them can be used as input and the other as output, and negative feedback control is performed from the output side to control the timing of each switch. However, the only difference is that the current is controlled in the opposite direction. On the other hand, in the asynchronous rectification method, since the switching diode 48 flows only in the forward current, the step-down DC converter and the step-up DC converter are different circuits.
 スイッチング回路30は、高周波でスイッチング素子をオン/オフするため、ノイズが課題となる場合が多い。スイッチング素子はパワートランジスタが使用されており、オフ時にサージ電圧やリンギング電圧(サージ/リンギング電圧)が発生する。この時、スイッチング回路30にはサージ/リンギング電流iが流れ、それがスイッチング回路30を使用したDCコンバータの高周波リンギングループに流れ、そのループに存在する寄生インダクタンスLによってL×di/dtのサージ/リンギング電圧が発生する。ここで、tは時間である。これがDCコンバータにおける入力コンデンサの端子にノイズを引き起こしたり、スイッチノードのノイズを引き起こしたり、インダクタや基板の寄生容量を介して出力端子や他の機器に伝わったりする。 Since the switching circuit 30 turns on / off the switching element at a high frequency, noise often becomes a problem. A power transistor is used as the switching element, and a surge voltage or a ringing voltage (surge / ringing voltage) is generated when the switching element is off. At this time, a surge / ringing current i flows through the switching circuit 30, which flows into a high-frequency ringing loop of a DC converter using the switching circuit 30, and a surge / ring of L × di / dt due to the parasitic inductance L existing in the loop. Ringing voltage is generated. Here, t is time. This causes noise at the input capacitor terminal in the DC converter, causes noise at the switch node, and is transmitted to the output terminal and other devices through the parasitic capacitance of the inductor and the substrate.
 スイッチング素子が直列に接続されているスイッチング回路30は、スイッチング電源においては、同期整流式コンバータに使用されており、以下、同期整流式降圧DC/DCコンバータを例として、その基本回路とノイズを考慮した等価回路について説明する。 The switching circuit 30 in which switching elements are connected in series is used in a synchronous rectifier converter in a switching power supply. Hereinafter, the basic circuit and noise are taken into consideration by taking a synchronous rectifier step-down DC / DC converter as an example. The equivalent circuit will be described.
 図6は、同期整流式降圧DC/DCコンバータの基本回路50である。入力電圧52に並列に入力コンデンサ54が接続されている。同期整流式降圧DC/DCコンバータは、変圧比に応じて入力電流の平均値が小さくなるが、瞬時的には出力電流と同じ電流が流れ、これを入力コンデンサ54で平均化する。入力電圧52はスイッチング回路30に接続され、ハイサイドスイッチング素子32とローサイドスイッチング素子40は、ゲートドライブ回路56からのパルス信号により、交互にオン/オフする制御が行われる。これにより、ハイサイドスイッチング素子32とローサイドスイッチング素子40の中間点の出力スイッチング波形は、スイッチング周波数に対応してパルス波形となる。ハイサイドスイッチング素子32とローサイドスイッチング素子40の中間点の出力スイッチング波形は、直列接続された出力インダクタ58と出力コンデンサ60による平滑回路を介して直流電圧となり、負荷62に供給される。 FIG. 6 shows a basic circuit 50 of a synchronous rectification step-down DC / DC converter. An input capacitor 54 is connected in parallel with the input voltage 52. In the synchronous rectification step-down DC / DC converter, the average value of the input current is reduced according to the transformation ratio, but the same current as the output current flows instantaneously, and this is averaged by the input capacitor 54. The input voltage 52 is connected to the switching circuit 30, and the high-side switching element 32 and the low-side switching element 40 are controlled to be turned on / off alternately by a pulse signal from the gate drive circuit 56. As a result, the output switching waveform at the midpoint between the high-side switching element 32 and the low-side switching element 40 becomes a pulse waveform corresponding to the switching frequency. The output switching waveform at the intermediate point between the high-side switching element 32 and the low-side switching element 40 becomes a DC voltage through a smoothing circuit including an output inductor 58 and an output capacitor 60 connected in series, and is supplied to the load 62.
 同期整流式降圧DC/DCコンバータのノイズは、スイッチング素子のオフ時に発生するサージ/リンギング電圧や、配線の寄生インダクタンスとスイッチング素子の寄生容量により発生している。配線の寄生インダクタンスとスイッチング素子の寄生容量によるノイズを考慮した等価回路を以下に説明する。 The noise of the synchronous rectification step-down DC / DC converter is generated by the surge / ringing voltage generated when the switching element is turned off, the parasitic inductance of the wiring, and the parasitic capacitance of the switching element. An equivalent circuit in consideration of noise due to the parasitic inductance of the wiring and the parasitic capacitance of the switching element will be described below.
 図7は、寄生インダクタンス、寄生容量を考慮した等価回路66である。スイッチング素子は選択する素子の種類にもよるため、ここではパワーMOSFETとし、ハイサイドスイッチング素子32をハイサイドパワーMOSFET80、ローサイドスイッチング素子40をローサイドパワーMOSFET82とした。 FIG. 7 shows an equivalent circuit 66 in consideration of parasitic inductance and parasitic capacitance. Since the switching element depends on the type of element to be selected, a power MOSFET is used here, the high side switching element 32 is a high side power MOSFET 80, and the low side switching element 40 is a low side power MOSFET 82.
 寄生要素は、入力コンデンサ54では寄生インダクタンス70-1とESR(Equivalent Serial Resistance)である。ESRは配線にも存在し、図7ではまとめてESR72-1とした。パワーMOSFETでは、ミラー容量とゲート容量は考慮せず、ボディダイオードと寄生容量を寄生要素とした。ハイサイドパワーMOSFET80では、ボディダイオード76-1と寄生容量74-1を、ローサイドパワーMOSFET82では、ボディダイオード76-2と寄生容量74-2を寄生要素として等価回路に示している。 Parasitic elements are the parasitic inductance 70-1 and ESR (Equivalent Serial Resistance) in the input capacitor 54. ESR is also present in the wiring, and in FIG. In the power MOSFET, the mirror capacitance and the gate capacitance are not considered, and the body diode and the parasitic capacitance are used as parasitic elements. In the high-side power MOSFET 80, the body diode 76-1 and the parasitic capacitance 74-1 are shown in the equivalent circuit, and in the low-side power MOSFET 82, the body diode 76-2 and the parasitic capacitance 74-2 are shown as parasitic elements.
 出力インダクタ58には、インダクタの巻き線間の寄生容量と基板パターンの寄生容量が発生し、浮遊容量78として示している。出力コンデンサ60では、入力コンデンサ54と同じく、寄生インダクタンス70-2とESR72-2が寄生要素である。配線、レイアウト、ビア等にも寄生インダクタンスが発生するが、図7では配線の寄生インダクタンス70-2、70-3、70-4で示した。 In the output inductor 58, a parasitic capacitance between the windings of the inductor and a parasitic capacitance of the substrate pattern are generated and are shown as a stray capacitance 78. In the output capacitor 60, like the input capacitor 54, the parasitic inductance 70-2 and the ESR 72-2 are parasitic elements. Parasitic inductances are also generated in wiring, layout, vias, etc., but are shown by wiring parasitic inductances 70-2, 70-3, 70-4 in FIG.
 ハイサイドパワーMOSFET80とローサイドパワーMOSFET82のオン/オフは、ゲートドライブ回路56のスイッチング波形により制御されるが、高周波ノイズは、主にハイサイドパワーMOSFET80とローサイドパワーMOSFET82がオフする時に発生し易い。ハイサイドパワーMOSFET80がオンになると、入力電圧52からハイサイドパワーMOSFET80を通して、ローサイドパワーMOSFET82の還流電流をキャンセルするように電流が流れ込む。 The on / off of the high-side power MOSFET 80 and the low-side power MOSFET 82 is controlled by the switching waveform of the gate drive circuit 56, but high-frequency noise is likely to occur mainly when the high-side power MOSFET 80 and the low-side power MOSFET 82 are turned off. When the high side power MOSFET 80 is turned on, a current flows from the input voltage 52 through the high side power MOSFET 80 so as to cancel the return current of the low side power MOSFET 82.
 ローサイドパワーMOSFET82の電流がゼロになってもローサイドパワーMOSFET82のボディダイオード76-2が有しているリカバリ機能により、蓄積されたキャリアがなくなるまでボディダイオード76-2に逆方向電流が流れる。このリカバリ電流は、入力コンデンサ54、ハイサイドパワーMOSFET80とローサイドパワーMOSFET82で構成されるループ(図7の破線参照)に流れる短絡電流iであり、ループに存在する全ての寄生容量にエネルギーが蓄積される。 Even when the current of the low-side power MOSFET 82 becomes zero, a reverse current flows through the body diode 76-2 until the accumulated carriers disappear due to the recovery function of the body diode 76-2 of the low-side power MOSFET 82. This recovery current is a short-circuit current i that flows in a loop (see the broken line in FIG. 7) composed of the input capacitor 54, the high-side power MOSFET 80, and the low-side power MOSFET 82, and energy is accumulated in all parasitic capacitances existing in the loop. The
 このエネルギーは、リカバリが働かなくなった瞬間に開放され、この時にループ内の寄生インダクタンスと寄生容量で共振が起き、サージやリンギングとなることにより、高周波ノイズが発生する。この時、ハイサイドパワーMOSFET80はオン状態で導通しているので、ハイサイドパワーMOSFET80の寄生容量74-1は関係なく、高周波リンギングの周波数は、ループの全ての寄生インダクタンスと寄生容量の共振周波数である。 This energy is released at the moment when the recovery stops working, and at this time, resonance occurs in the parasitic inductance and parasitic capacitance in the loop, resulting in surge and ringing, generating high frequency noise. At this time, since the high-side power MOSFET 80 is turned on and is conductive, the parasitic capacitance 74-1 of the high-side power MOSFET 80 is not related, and the frequency of the high-frequency ringing is the resonance frequency of all the parasitic inductances and parasitic capacitances of the loop. is there.
 ハイサイドパワーMOSFET80とローサイドパワーMOSFET82のオフ時の数百MHzのノイズは、高di/dtの電流サージとして入力コンデンサ54、ハイサイドパワーMOSFET80とローサイドパワーMOSFET82の高周波リンギングループを循環する。これによって、入力コンデンサ54にはdi/dtに依存したサージ電圧を発生させ、ハイサイドパワーMOSFET80とローサイドパワーMOSFET82には、電圧Vに対応したdV/dtのリンギング電圧が発生する。ループを流れる高周波のリンギング電流は、ループの面積に依存した磁束を発生させ、この磁束が外部へ向かって放射されるため、電磁波として機器の基板のストリップラインやループにおいて電磁誘導を引き起こす The noise of several hundred MHz when the high-side power MOSFET 80 and the low-side power MOSFET 82 are turned off circulates in the high frequency ringing loop of the input capacitor 54, the high-side power MOSFET 80 and the low-side power MOSFET 82 as a high di / dt current surge. As a result, a surge voltage depending on di / dt is generated in the input capacitor 54, and a ringing voltage of dV / dt corresponding to the voltage V is generated in the high-side power MOSFET 80 and the low-side power MOSFET 82. The high-frequency ringing current that flows through the loop generates a magnetic flux that depends on the area of the loop, and this magnetic flux is radiated to the outside, causing electromagnetic induction in the stripline and loop of the equipment substrate as an electromagnetic wave.
 スイッチング回路30には、サージ/リンギング電圧を抑制することを目的としたサージ吸収素子やスナバ回路が設けられる。さらにスイッチング素子を過電流から保護するため、例えば同期整流方式の降圧DCコンバータでは、出力電圧に過渡応答などによるオーバーシュートが発生すると、出力からシンクして電流を逆流させて入力に回生して出力電圧を強制的に下げるという動作を行なう回生回路が使用されている。これらの保護回路に加えて、ゲートドライブ信号による過電流保護等が行われている。 The switching circuit 30 is provided with a surge absorbing element and a snubber circuit for the purpose of suppressing a surge / ringing voltage. Furthermore, to protect the switching element from overcurrent, for example, in a synchronous rectification step-down DC converter, if an overshoot occurs due to a transient response or the like in the output voltage, the output is sunk from the output to reverse the current and regenerate to the input for output. A regenerative circuit that performs an operation of forcibly lowering the voltage is used. In addition to these protection circuits, overcurrent protection by a gate drive signal is performed.
 図8は、DC/DCコンバータに使用されているスイッチング回路30、スイッチング回路30のスイッチング素子をオン/オフして制御するゲートドライブ回路56と、スイッチング回路30の保護回路90を示したブロック図である。 FIG. 8 is a block diagram showing the switching circuit 30 used in the DC / DC converter, the gate drive circuit 56 that controls the switching elements of the switching circuit 30 by turning on / off, and the protection circuit 90 of the switching circuit 30. is there.
 ゲートドライブ回路56からの制御信号で、スイッチング回路30にあるハイサイドパワーMOSFET80とローサイドパワーMOSFET82が交互にオン/オフされる。ゲートドライブ回路56は、デッドタイムを設けて、スイッチング回路30のスイッチング素子が、オン/オフされるスイッチング時に発生するdv/dtによってゲートが誤点狐することを回避し、パルス状の短絡電流が流れることによる加熱やスイッチング素子の破壊を防止している。 In response to a control signal from the gate drive circuit 56, the high-side power MOSFET 80 and the low-side power MOSFET 82 in the switching circuit 30 are alternately turned on / off. The gate drive circuit 56 provides a dead time to prevent the gate of the switching element of the switching circuit 30 from being erroneously turned on by dv / dt generated during switching that is turned on / off. Heating due to flow and switching element destruction are prevented.
 図9は、デッドタイムを説明する図である。ハイサイドゲート信号は、ハイサイドパワーMOSFET80のゲートに入力され、ローサイドゲート信号は、ローサイドパワーMOSFET82のゲートに入力される。デッドタイムは、ハイサイドMOSFET80とローサイドパワーMOSFET82が同時にオンとなることを避けるために、ハイサイドゲート信号がオフとなってから一定時間遅延させる第1デッドタイムを設けて、ローサイドゲート信号をオンにする。次に、ローサイドゲート信号がオフとなったら、一定時間遅延させる第2デッドタイムを設けて、ハイサイドゲート信号をオンにする。この第1デッドタイムと第2デッドタイムの設定により、ハイサイドパワーMOSFET80とローサイドパワーMOSFET82の短絡を防止している。 FIG. 9 is a diagram for explaining dead time. The high side gate signal is input to the gate of the high side power MOSFET 80, and the low side gate signal is input to the gate of the low side power MOSFET 82. In order to avoid the high-side MOSFET 80 and the low-side power MOSFET 82 being simultaneously turned on, the dead time is provided with a first dead time that is delayed for a predetermined time after the high-side gate signal is turned off, and the low-side gate signal is turned on. To do. Next, when the low-side gate signal is turned off, a second dead time that is delayed for a predetermined time is provided to turn on the high-side gate signal. By setting the first dead time and the second dead time, a short circuit between the high side power MOSFET 80 and the low side power MOSFET 82 is prevented.
 デッドタイムは、スイッチング素子のスイッチング時間よりも長く設定する必要がある。デッドタイムが十分であってもスイッチング素子のミラー容量を抜けてくる微小なパルス状電流が流れる。デッドタイムが不足していると、大きな短絡電流が流れ、スイッチング素子の破壊まではともかく、ノイズとなってスイッチング動作を不安定にさせる要因となる。 Dead time must be set longer than the switching time of the switching element. Even if the dead time is sufficient, a minute pulse current flowing through the mirror capacitance of the switching element flows. If the dead time is insufficient, a large short-circuit current flows, causing noise and destabilizing the switching operation regardless of the destruction of the switching element.
 スイッチング回路30は、これらのゲートドライブ回路56と保護回路90により安定な動作が行われているが、これらの回路を電気的に接続する配線は、寄生インダクタンスを抑えるためになるべく短くする必要がある。特にサージ吸収用の素子やスナバ回路は、スイッチング電源のスイッチング素子で発生したノイズを抑制するために、スイッチング素子の近くに配置することが好ましい。 The switching circuit 30 is stably operated by the gate drive circuit 56 and the protection circuit 90, but the wiring that electrically connects these circuits needs to be as short as possible to suppress the parasitic inductance. . In particular, the surge absorbing element and the snubber circuit are preferably arranged near the switching element in order to suppress noise generated in the switching element of the switching power supply.
 図10は、スイッチング回路30にスナバ回路92を接続した場合に、スナバ回路92の配線に発生する寄生インダクタンス70-10を考慮した電気的等価回路を示している。スナバ回路92の搭載に配線を必要とするため、新たな寄生インダクタンス70-10を発生させることになる。さらに、スナバ回路92を他の回路素子と同一のプリント基板に搭載しようとすると、他の回路素子の配置も変わり、配線も長くしなければならず、寄生インダクタンスも増加する。 FIG. 10 shows an electrical equivalent circuit in consideration of the parasitic inductance 70-10 generated in the wiring of the snubber circuit 92 when the snubber circuit 92 is connected to the switching circuit 30. Since wiring is required for mounting the snubber circuit 92, a new parasitic inductance 70-10 is generated. Furthermore, if the snubber circuit 92 is to be mounted on the same printed circuit board as other circuit elements, the arrangement of the other circuit elements also changes, the wiring must be lengthened, and the parasitic inductance increases.
 本発明は、保護回路を外部電極14-1、14-2に接続して搭載することができるので、保護回路接続用の配線を短くすることができ、新たな寄生インダクタンスの発生を抑えることができる。さらに、他の回路素子の配置も変えることなく、配線も長くする必要が無い。 In the present invention, since the protection circuit can be mounted by connecting to the external electrodes 14-1 and 14-2, the wiring for connecting the protection circuit can be shortened and generation of new parasitic inductance can be suppressed. it can. Furthermore, it is not necessary to lengthen the wiring without changing the arrangement of other circuit elements.
 外部電極外部搭載部品として、スイッチング波形の寄生成分に起因するサージを吸収する保護回路が接続されている。 Protective circuit that absorbs surges caused by parasitic components of the switching waveform is connected as external electrode externally mounted components.
 この保護回路には半導体素子が使用され、サージ吸収用としてアバランシェダイオードが使用されている。 The semiconductor circuit is used for this protection circuit, and an avalanche diode is used for surge absorption.
 また、保護回路は、少なくとも抵抗、ダイオード又はコンデンサのいずれか1つを含むスナバ回路である。 The protection circuit is a snubber circuit including at least one of a resistor, a diode, and a capacitor.
 本発明では、このサージ吸収用の素子やスナバ回路92を、モールドケース12の外表面に露出した外部電極14-1、14-2に接続して搭載することができるので、モールドケース12の内部にあるプリント基板上にスナバ回路92の搭載スペースを必要とせず、スナバ回路92への配線も短くでき、他の回路素子の配置、配線も変える必要が無い。さらに、寄生要素は、スナバ回路92の配線にも寄生インダクタンス70-10が存在するが、外部電極14-1、14-2との距離を短くできるため、寄生インダクタンス70-10の値は小さい。 In the present invention, the surge absorbing element and the snubber circuit 92 can be connected to and mounted on the external electrodes 14-1 and 14-2 exposed on the outer surface of the mold case 12. The space for mounting the snubber circuit 92 on the printed circuit board is not required, the wiring to the snubber circuit 92 can be shortened, and there is no need to change the arrangement and wiring of other circuit elements. Further, the parasitic element has a parasitic inductance 70-10 in the wiring of the snubber circuit 92, but since the distance to the external electrodes 14-1 and 14-2 can be shortened, the value of the parasitic inductance 70-10 is small.
 リンギング電圧を吸収するスナバ回路92は、寄生インダクタンスと寄生容量を基に計算式もあり、シミュレーションも可能である。従来はこのシミュレーション手段により、スナバ回路構成と電子部品の選定を行ってプリント基板に搭載しパッケージしていた。電子部品は実測によりその値を修正して搭載したとしても、実際に使用する場合には、様々な寄生要素が発生し、スナバ回路をさらに修正、即ち、より最適な電子部品にする必要があるが、実装状態に合わせて実測した最適なスナバ回路92の選択はできず、設計の自由度が制限されていた。 The snubber circuit 92 that absorbs the ringing voltage has a calculation formula based on parasitic inductance and parasitic capacitance, and can be simulated. Conventionally, a snubber circuit configuration and electronic parts are selected by this simulation means and mounted on a printed circuit board and packaged. Even if an electronic component is mounted with its value corrected by actual measurement, when it is actually used, various parasitic elements are generated, and the snubber circuit needs to be further corrected, that is, a more optimal electronic component is required. However, the optimum snubber circuit 92 actually measured according to the mounting state cannot be selected, and the degree of design freedom is limited.
 本発明では、スナバ回路用の外部電極をモールドケースの外表面に設けてあり、ユーザが実際に使用する実装状態で、サージ/リンギング電圧を測定しながら自由に設計できる。このため、最適なサージ/リンギング電圧の抑制が可能となる。 In the present invention, the external electrode for the snubber circuit is provided on the outer surface of the mold case, and can be freely designed while measuring the surge / ringing voltage in the mounting state that the user actually uses. Therefore, it is possible to suppress the optimum surge / ringing voltage.
 波形の測定にはノイズの影響を受け難くするために、例えば帯域が1GHzのオシロスコープを用いて受動プローブとマウントジャックを使用し、FETプローブを使用する等に注意しながら、サージ/リンギング電圧を測定する。その結果を基にサージ/リンギング電圧を抑制するスナバ回路92を設計し実装することができる。
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In order to make the waveform measurement less susceptible to noise, measure the surge / ringing voltage, for example, using an oscilloscope with a bandwidth of 1 GHz, using a passive probe and mount jack, and using an FET probe. To do. Based on the result, the snubber circuit 92 for suppressing the surge / ringing voltage can be designed and mounted.
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 サージ/リンギング電圧を抑制する保護回路は、過電圧検出保護用の電子部品とノイズ除去用の電子部品からなる電気回路であり、様々な形態が考えられる。以下に主な例を説明する。 The protection circuit that suppresses the surge / ringing voltage is an electric circuit composed of an electronic component for overvoltage detection protection and an electronic component for noise removal, and various forms are conceivable. The main examples are described below.
 図11は、サージ吸収用のアバランシェダイオード94を外部電極14-1、14-2に接続した例である。アバランシェダイオード94は、直列接続されたハイサイドスイッチング素子32とローサイドスイッチング素子40の両端部、即ち、外部電極14-1、14―2を介してHドレイン36とLソース46に接続されている。アバランシェダイオード94は、特定の逆電圧でアバランシェ降伏を起こし、過電圧から回路を保護するクランパである。近年パワーモジュールは、高電圧を高速にスイッチングすることが要求されているが、例えばシリコンアバランシェダイオードは数kVの降伏電圧を持つものもある。アバランシェダイオードは、出力スイッチング波形の時間領域に注目して、サージ電圧(又は電流)のピーク値を検出しカットすることを目的としている。カットする電圧(又は電流)の最大値は、アバランシェダイオードの降伏電圧で決定される。また、周波数特性は、アバランシェダイオード94の回復時間に依存する。 FIG. 11 shows an example in which a surge absorbing avalanche diode 94 is connected to external electrodes 14-1 and 14-2. The avalanche diode 94 is connected to the H drain 36 and the L source 46 via both ends of the high side switching element 32 and the low side switching element 40 connected in series, that is, the external electrodes 14-1 and 14-2. The avalanche diode 94 is a clamper that causes an avalanche breakdown at a specific reverse voltage and protects the circuit from an overvoltage. In recent years, power modules are required to switch a high voltage at high speed. For example, a silicon avalanche diode has a breakdown voltage of several kV. The avalanche diode is intended to detect and cut the peak value of the surge voltage (or current) by paying attention to the time domain of the output switching waveform. The maximum value of the voltage (or current) to be cut is determined by the breakdown voltage of the avalanche diode. The frequency characteristic depends on the recovery time of the avalanche diode 94.
 外部電極14-1、14-2に接続するクランパは、アバランシェダイオードの他、スナバダイオードとスナバツェナーダイオードを逆向きに直列接続してもよい。 As the clamper connected to the external electrodes 14-1 and 14-2, a snubber diode and a snubber Zener diode may be connected in series in the reverse direction in addition to the avalanche diode.
 図12は、スナバ回路92-1をスナバ抵抗100(以下、スナバ回路92に使用される電子部品は、スナバを冠した名称とする。)とスナバコンデンサ102とした例である。スナバ抵抗100とスナバコンデンサ102を直列接続したスナバ回路92-1は、一種のローパスフィルタであり、カットオフ周波数を高周波リンギングの周波数以下にすることが必要となる。 FIG. 12 shows an example in which the snubber circuit 92-1 is a snubber resistor 100 (hereinafter, an electronic component used in the snubber circuit 92 is named with a snubber) and a snubber capacitor 102. The snubber circuit 92-1 in which the snubber resistor 100 and the snubber capacitor 102 are connected in series is a kind of low-pass filter, and the cut-off frequency is required to be equal to or lower than the high-frequency ringing frequency.
 スナバコンデンサ102のみの使用は、エネルギーの吸収も早いが放出も早く、出力スイッチング波形の立ち上がり、立下りの急峻な電圧サージを吸収するが、高周波リンギングの抑制が十分でない場合がある。0901f02-formula02.gif0901f02-formula02.gifこのような場合に、スナバコンデンサ86に、スナバ抵抗100を直列に接続してエネルギーの吸収・放出を遅くする。また、高調波成分をカットしているため、出力スイッチング波形の立ち上がり時間と立下り時間が緩慢になる。 The use of only the snubber capacitor 102 absorbs energy rapidly but releases it quickly and absorbs a sharp voltage surge at the rise and fall of the output switching waveform, but there are cases where the suppression of high-frequency ringing is not sufficient. In such a case, the snubber capacitor 86 is connected in series with the snubber capacitor 86 to slow down energy absorption / release. [0901f02-formula02.gif0901f02-formula02.gif] In addition, since the harmonic component is cut, the rise time and fall time of the output switching waveform become slow.
 図13は、直列接続されたスナバ抵抗100とスナバコンデンサ102に、スナバダイオード104を並列接続したスナバ回路92-2である。スナバ回路92-2は、直列接続されたハイサイドスイッチング素子32とローサイドスイッチング素子40の両端部、即ち、外部電極14-1、14―2を介してHドレイン36とLソース46に接続されている。スナバダイオード104により、スナバコンデンサ102に蓄積されたエネルギーの放出を促している。スナバダイオード104はアノードとカソードの向きを変えて、スナバコンデンサ102にエネルギーの蓄積を促してもよい。また、スナバツェナーダイオードとしてもよい。 FIG. 13 shows a snubber circuit 92-2 in which a snubber diode 104 is connected in parallel to a snubber resistor 100 and a snubber capacitor 102 connected in series. The snubber circuit 92-2 is connected to both ends of the high-side switching element 32 and the low-side switching element 40 connected in series, that is, to the H drain 36 and the L source 46 via the external electrodes 14-1 and 14-2. Yes. The snubber diode 104 urges the energy stored in the snubber capacitor 102 to be released. The snubber diode 104 may change the direction of the anode and the cathode to encourage the snubber capacitor 102 to accumulate energy. Further, it may be a snubber Zener diode.
 図14では、直列接続されたスナバ抵抗100とスナバコンデンサ102に、スナバダイオード104を並列接続したスナバ回路92-2を、ハイサイドスイッチング素子32とローサイドスイッチング素子40に個別に接続している。外部電極は、ハイサイドスイッチング素子32のHドレイン36から外部電極14-1、ハイサイドスイッチング素子32のHソース38から外部電極14-3、ローサイドスイッチング素子40のHドレイン44から外部電極14-4、ローサイドスイッチング素子40のLソース46から外部電極14-2にそれぞれ接続されている。 In FIG. 14, a snubber circuit 92-2, in which a snubber diode 104 is connected in parallel to a snubber resistor 100 and a snubber capacitor 102 connected in series, is individually connected to the high-side switching element 32 and the low-side switching element 40. The external electrodes are the external electrode 14-1 from the H drain 36 of the high side switching element 32, the external electrode 14-3 from the H source 38 of the high side switching element 32, and the external electrode 14-4 from the H drain 44 of the low side switching element 40. The low-side switching element 40 is connected from the L source 46 to the external electrode 14-2.
 1つのスナバ回路92-2は、外部電極14-1と外部電極14-3に接続され、さらに他の1つのスナバ回路92-2は、外部電極14-4と外部電極14-2に接続されている。このように、スナバ回路を個別のスイッチング素子に接続してもよい。勿論、スナバ回路は他の回路構成でもよく、例えば、図12に示したスナバ回路92-1でもよく、スナバ回路92-1とスナバ回路92-2との組み合わせでもよい。図14においては、外部電極14-3と外部電極14-4は、共通の電極とすることもできる。 One snubber circuit 92-2 is connected to the external electrode 14-1 and the external electrode 14-3, and another snubber circuit 92-2 is connected to the external electrode 14-4 and the external electrode 14-2. ing. In this way, the snubber circuit may be connected to individual switching elements. Of course, the snubber circuit may have another circuit configuration, for example, the snubber circuit 92-1 shown in FIG. 12, or a combination of the snubber circuit 92-1 and the snubber circuit 92-2. In FIG. 14, the external electrode 14-3 and the external electrode 14-4 may be a common electrode.
 図15は、スナバ回路92-2の一部の電子回路部品をケース内のプリント板に搭載し、他の電子部品を外部電極14-1、14-5に接続して、全体としてスナバ回路92-2を構成する場合の例を示している。図15では、スナバ回路92-2のスナバダイオード104を外部電極14-1、14-5に接続しているが、スナバ抵抗100又はスナバコンデンサ102を外部電極14-1、14-5に接続する構成にしてもよい。勿論、スナバ抵抗100、スナバコンデンサ102及びスナバダイオード104のいずれか2つを外部電極14-1、14-5に接続する構成にしてもよい。 In FIG. 15, a part of the electronic circuit component of the snubber circuit 92-2 is mounted on the printed board in the case, and the other electronic components are connected to the external electrodes 14-1 and 14-5. -2 is shown as an example. In FIG. 15, the snubber diode 104 of the snubber circuit 92-2 is connected to the external electrodes 14-1 and 14-5, but the snubber resistor 100 or the snubber capacitor 102 is connected to the external electrodes 14-1 and 14-5. It may be configured. Of course, any two of the snubber resistor 100, the snubber capacitor 102, and the snubber diode 104 may be connected to the external electrodes 14-1 and 14-5.
 図16は、ハイサイドスイッチング素子32とローサイドスイッチング素子40に対して個別に接続するスナバ回路92-2のうち、1つをケース内のプリント板に内部搭載し、他の電子部品を外部電極14-1、14-3に接続して外部搭載とした例である。図16では、ローサイドスイッチング素子40に接続するスナバ回路92-2を内部搭載とし、ハイサイドスイッチング素子32に接続するスナバ回路92-2を外部搭載としているが、ハイサイドスイッチング素子32に接続するスナバ回路92-2を内部搭載とし、ローサイドスイッチング素子40に接続するスナバ回路92-2を外部搭載としてもよい。 FIG. 16 shows that one of the snubber circuits 92-2 individually connected to the high-side switching element 32 and the low-side switching element 40 is mounted on the printed board in the case, and the other electronic components are connected to the external electrode 14. -1 and 14-3 are externally mounted examples. In FIG. 16, the snubber circuit 92-2 connected to the low-side switching element 40 is mounted internally, and the snubber circuit 92-2 connected to the high-side switching element 32 is mounted externally, but the snubber connected to the high-side switching element 32 is mounted. The circuit 92-2 may be mounted internally, and the snubber circuit 92-2 connected to the low-side switching element 40 may be mounted externally.
 パワーモジュールのスイッチング素子に使用されているパワーMOSFETは、縦型と横型の2種類に分類でき、特に縦型は高耐圧化と低オン抵抗化に適している。また、縦型を多層構造に実装して、低オン抵抗化と共に配線を短くできるため、寄生インダクタンスを抑止できる。 ∙ Power MOSFETs used for switching elements in power modules can be classified into two types, vertical and horizontal, and the vertical type is particularly suitable for high breakdown voltage and low on-resistance. In addition, since the vertical type can be mounted in a multilayer structure to reduce the on-resistance and shorten the wiring, parasitic inductance can be suppressed.
 次に、パワーモジュールのスイッチング回路に使用されているスイッチング素子について説明する。 Next, switching elements used in the power module switching circuit will be described.
 スイッチング素子としては、金属酸化物半導体電界効果トランジスタ又はフォワードダイオードを備えた絶縁ゲートバイポーラトランジスタが使用でき、IGBT(Insulated Gate Bipolar Transistor)を使用してもよい。IGBTは、負荷電流を転流させるためのFWD(Free Wheeling Diode)が必要となるが、FWD内臓タイプのIGBTを使用することにより、部品点数を増加させることなく使用できる。 As the switching element, a metal oxide semiconductor field effect transistor or an insulated gate bipolar transistor having a forward diode can be used, and an IGBT (Insulated Gate Bipolar Transistor) may be used. The IGBT requires an FWD (Free Wheeling Diode) for commutating the load current, but can be used without increasing the number of parts by using an IGBT with a built-in FWD.
 IGBTは、例えばnチャネル型の場合、パワーMOSFETのドレイン側にp+層を追加した構造となっており、パワーMOSFETよりも大電流での低オン抵抗化が可能な素子である。 For example, in the case of the n-channel type, the IGBT has a structure in which a p + layer is added on the drain side of the power MOSFET, and is an element capable of lowering the on-resistance with a larger current than the power MOSFET.
 高耐圧高速スイッチングが可能な次世代のパワー半導体デバイス用の材料としてIII族窒化物、例えば、GaN(ガリウム・ナイトライド)系の半導体が期待されている。GaN系の半導体デバイスはSi(シリコン)と比較して広いバンドギャップを備え、Siの半導体デバイスと比較して、高い耐圧、低い損失が実現できる。GaN系のトランジスタでは、一般に、2次元電子ガス(2DEG)をキャリアとするHEMT(High Electron Mobility Transistor)構造である(以下、GaN―HEMT構造のスイッチング素子をGaNと略す)。スイッチング素子としては、さらにSiC(Silicon Carbide)からなる半導体素子もある(以下、SiCからなる半導体素子をSiCと略す)。絶縁破壊電界強度がシリコンの10倍、バンドギャップがシリコンの3倍と優れており、現在1200V、100Aクラスのデバイスがある。オン抵抗をシリコンと同じ程度の面積抵抗率である10mΩ・cmまで下げた場合は、1600Vの耐圧が得られている。 Group III nitrides, for example, GaN (gallium nitride) -based semiconductors are expected as materials for next-generation power semiconductor devices capable of high-voltage and high-speed switching. A GaN-based semiconductor device has a wider band gap than Si (silicon), and can achieve higher breakdown voltage and lower loss than Si semiconductor devices. A GaN-based transistor generally has a HEMT (High Electron Mobility Transistor) structure using a two-dimensional electron gas (2DEG) as a carrier (hereinafter, a GaN-HEMT structure switching element is abbreviated as GaN). As a switching element, there is also a semiconductor element made of SiC (Silicon Carbide) (hereinafter, a semiconductor element made of SiC is abbreviated as SiC). The dielectric breakdown electric field strength is 10 times that of silicon and the band gap is 3 times that of silicon, and there are currently devices of the 1200V, 100A class. When the on-resistance is lowered to 10 mΩ · cm 2 which is the same area resistivity as that of silicon, a withstand voltage of 1600 V is obtained.
 GaNは、電子移動度や絶縁破壊電界強度の点でSiCに勝っているため、大電力変換容量に向いている。一方、SiCは熱伝導率がGaNに対して約3倍高く、高温での使用に向いている。 Since GaN is superior to SiC in terms of electron mobility and dielectric breakdown electric field strength, it is suitable for high power conversion capacity. On the other hand, SiC has a thermal conductivity approximately three times higher than that of GaN, and is suitable for use at high temperatures.
 最近では、ガリウム・オキサイド(酸化ガリウムGa)のパワーデバイスも開発されている。ガリウム・オキサイドのバンドギャプは、4.7~4.9であり、GaNやSiCの3.3~3.4よりはるかに高く、低オン抵抗化が図れる。このため、さらなる高効率・高性能のパワーデバイスが可能である。 Recently, power devices of gallium oxide (gallium oxide Ga 2 O 3 ) have also been developed. The band gap of gallium oxide is 4.7 to 4.9, which is much higher than 3.3 to 3.4 of GaN and SiC, and can achieve low on-resistance. For this reason, a further highly efficient and high performance power device is possible.
 本発明によるパワーモジュールは、これらGaN,SiC及びガリウム・オキサイドより成る素子であるスイッチング素子や整流素子の何れも使用可能である。 The power module according to the present invention can use any of a switching element and a rectifying element which are elements made of GaN, SiC and gallium oxide.
 GaNは、Siデバイスと比べ低オン抵抗・高速スイッチングに適しているが、ノーマリーオン(Depletion‐mode)動作となり、フェイルセーフ(Fail‐safe)の観点から、ノーマリーオフ(Enhancement-mode)動作が可能なデバイスが今後期待されている。また、SiCは、酸化膜の信頼性やチャネル移動度の劣化などから、特性・信頼性の面など解決しなければならない課題があるが、今後期待されるデバイスである。 GaN is suitable for low on-resistance and high-speed switching compared to Si devices, but it is normally-on (depletion-mode) operation, and is normally-off (enhancement-mode) operation from the viewpoint of fail-safe. Devices that can be used are expected in the future. Further, SiC has a problem that must be solved in terms of characteristics and reliability due to deterioration of oxide film reliability and channel mobility, but is a device expected in the future.
 ノーマリーオン型のパワーデバイスを、ノーマリーオフ型のパワーデバイス動作をさせるため、ノーマリーオフ型のスイッチング素子とカスコ―ド接続してノーマリーオフとして駆動制御できる。 Since normally-on-type power devices operate normally-off type power devices, they can be driven and controlled as normally-off by cascode connection with normally-off type switching devices.
 図17は、パッケージされたカスコ―ド接続素子110の例であり、パッケージ底面と内部等価回路を示している、カスコ―ド接続は、ノーマリ―オン型の第1スイッチング素子112とノーマリーオフ型の第2スイッチング素子114で構成されている。第1スイッチング素子112のソースが第2スイッチング素子114のドレインに接続され、第1スイッチング素子112のゲートが第2スイッチング素子114のソースに接続されている。第2スイッチング素子114のゲートにゲート信号が印加されると第2スイッチング素子114のドレインに電流が流れ、この電流は、第1スイッチング素子112のソース電流に変換される。このソース電流が第1スイッチング素子112のドレイン電流となる。第1スイッチング素子112のドレインと第2スイッチング素子114のゲート間のインピーダンスは高く、周波数特性に優れた回路構成である。 FIG. 17 shows an example of a packaged cascode connection element 110, showing a package bottom surface and an internal equivalent circuit. The cascode connection includes a normally-on type first switching element 112 and a normally-off type. The second switching element 114. The source of the first switching element 112 is connected to the drain of the second switching element 114, and the gate of the first switching element 112 is connected to the source of the second switching element 114. When a gate signal is applied to the gate of the second switching element 114, a current flows to the drain of the second switching element 114, and this current is converted into a source current of the first switching element 112. This source current becomes the drain current of the first switching element 112. The impedance between the drain of the first switching element 112 and the gate of the second switching element 114 is high, and the circuit configuration is excellent in frequency characteristics.
 パッケージされたカスコ―ド接続素子110では、パッケージ底面に、第1スイッチング素子112のドレイン電極D、第2スイッチング素子114のゲート電極G、及び、第1スイッチング素子112のゲートと第2スイッチング素子114のソースが共通に接続された電極Sと電極Kがある。このため、ノーマリーオン型のパワーデバイスをノーマリーオフ型のパワーデバイスと同様の扱いで使用することができる。 In the packaged cascode connection element 110, the drain electrode D of the first switching element 112, the gate electrode G of the second switching element 114, and the gate of the first switching element 112 and the second switching element 114 are formed on the bottom surface of the package. There are an electrode S and an electrode K to which their sources are connected in common. For this reason, a normally-on type power device can be used in the same manner as a normally-off type power device.
 図18は、カスコ―ド接続回路にGaN及び/又はSiCを使用した例を示している。GaN及び/又はSiCは、図17に示したカスコ―ド接続素子110の第1スイッチング素子112にGaN及び/又はSiCを使用して、高速・高耐圧化を図っている。 FIG. 18 shows an example in which GaN and / or SiC is used for the cascade connection circuit. GaN and / or SiC uses GaN and / or SiC for the first switching element 112 of the cascade connection element 110 shown in FIG.
 図19は、カスコ―ド接続回路をスイッチング回路に適用した例を示している。GaN又はSiCからなるスイッチング素子112-1とMOSFET114-1をカスコ―ド接続したハイサイドスイッチング素子と、同じくGaN又はSiCからなるスイッチング素子112-2とMOSFET114-2をカスコ―ド接続したローサイドサイドスイッチング素子とが直列接続されている。これにより、高速・高耐圧のノーマリーオン型のパワー素子をノーマリ―オフ型のパワー素子として扱え、本発明のパワーモジュールに適用可能である。 FIG. 19 shows an example in which the cascade connection circuit is applied to a switching circuit. A high-side switching element in which the switching element 112-1 made of GaN or SiC and the MOSFET 114-1 are cascade-connected, and a low-side side switching in which the switching element 112-2 and the MOSFET 114-2 each made of GaN or SiC are also cascade-connected. The element is connected in series. As a result, a normally-on type power element with high speed and high withstand voltage can be handled as a normally-off type power element, and can be applied to the power module of the present invention.
 従来のGaNは、ゲートに電圧を印加しない状態でドレイン電流が流れてしまうノーマリーオン特性を示すものが多く、カスコ―ド接続としたり、ドレイン電流を止めるためにゲートに負電圧を印加したりする必要があった。これに対して、ドレイン電流を流すための電子の数をデバイスのチャネル全体で少なくし、さらにゲート構造を少し工夫することでノーマリーオフを実現することが可能である。また、P型GaN材料の持つ内部的な電気的作用でP型GaNのあるゲート下のみの電子を消滅させ、オン抵抗を低減させたまま、ノーマリーオフを実現することもできる。当然ながら、ノーマリーオフ特性を備えたGaNも、本発明のパワーモジュールに適用可能であり、高耐圧、高効率で小型のパワーモジュールが実現できる。
(実施例1)
Many conventional GaN exhibit normally-on characteristics in which drain current flows when no voltage is applied to the gate. Cascade connection is used, and a negative voltage is applied to the gate to stop the drain current. There was a need to do. On the other hand, normally-off can be realized by reducing the number of electrons for flowing the drain current in the entire channel of the device and further devising the gate structure. Also, normally-off can be realized while the on-resistance is reduced by annihilating electrons only under the gate where the P-type GaN is present by the internal electrical action of the P-type GaN material. Naturally, GaN having normally-off characteristics can also be applied to the power module of the present invention, and a small power module with high breakdown voltage and high efficiency can be realized.
Example 1
 図20は、本発明を適用した同期整流式降圧DC/DCコンバータの実施例1の回路図である。入力電圧52は395Vであり、入力コンデンサ54は47μFの電解コンデンサを2個並列に接続している。スイッチング回路30は、ハイサイドパワーMOSFET80とローサイドパワーMOSFET82を直列接続し、ゲートには制御部からのスイッチング波形が入力されている。出力インダクタ58のインダクタンスは24.9μHであり、出力コンデンサ60の容量は0.0022μFである。 FIG. 20 is a circuit diagram of Example 1 of a synchronous rectification step-down DC / DC converter to which the present invention is applied. The input voltage 52 is 395 V, and the input capacitor 54 has two 47 μF electrolytic capacitors connected in parallel. The switching circuit 30 has a high-side power MOSFET 80 and a low-side power MOSFET 82 connected in series, and a switching waveform from the control unit is input to the gate. The inductance of the output inductor 58 is 24.9 μH, and the capacitance of the output capacitor 60 is 0.0022 μF.
 同期整流式DC/DCコンバータの実施例1では、パワーMOSFETを直列に接続したスイッチング回路30を本発明のパワーモジュール20としている。このパワーモジュール20では、底面にパット形状の外部電極14-1~4を設け、スイッチング回路30とビアで接続する。実施例では、ノイズ除去用のコンデンサ22をモジュールの外部搭載部品としているため外部電極は2個でよく、外部電極14-1と外部電極14-2のみとした。コンデンサ22を外部搭載部品としているため、回路基板でのコンデンサ22の搭載スペースが不要となり、他の電子部品への配線が短くできる。 In the first embodiment of the synchronous rectification DC / DC converter, the switching circuit 30 in which power MOSFETs are connected in series is used as the power module 20 of the present invention. In the power module 20, pad-shaped external electrodes 14-1 to 14-4 are provided on the bottom surface and connected to the switching circuit 30 by vias. In the embodiment, since the noise removing capacitor 22 is an externally mounted component of the module, only two external electrodes are required, and only the external electrode 14-1 and the external electrode 14-2 are used. Since the capacitor 22 is an externally mounted component, a space for mounting the capacitor 22 on the circuit board is not required, and wiring to other electronic components can be shortened.
 外部電極14-1と外部電極14-2へは、図11で示したアバランシェダイオードや、図12と図13で示したスナバ回路を搭載してもよく、ノイズを測定しながらの設計ができ、低ノイズのスイッチング電源を得ることができた。
(実施例2)
The avalanche diode shown in FIG. 11 or the snubber circuit shown in FIG. 12 and FIG. 13 may be mounted on the external electrode 14-1 and the external electrode 14-2, and design can be performed while measuring noise. A low noise switching power supply was obtained.
(Example 2)
 実施例2では、図20で示した外部電極14-1~4を使用し、ハイサイドパワーMOSFET80とローサイドパワーMOSFET82に対する個別スナバ回路を形成した。外部電極14-1~4へは、図14で示したスナバ回路92-2を搭載した。スナバ回路92-2の抵抗やコンデンサは、ノイズを測定しながらの設計ができ、低ノイズのスイッチング電源を得ることができた。 In Example 2, individual snubber circuits for the high-side power MOSFET 80 and the low-side power MOSFET 82 were formed using the external electrodes 14-1 to 14-4 shown in FIG. The snubber circuit 92-2 shown in FIG. 14 is mounted on the external electrodes 14-1 to 14-4. The resistance and capacitor of the snubber circuit 92-2 could be designed while measuring noise, and a low noise switching power supply could be obtained.
 図21は、実施例1と実施例2の測定結果であり、図20の矢印で示した箇所の電圧波形をFETプローブで測定しており、スイッチング回路の出力電圧を測定している。図21(A)は、シミュレーション手段により、実施例1におけるコンデンサ容量、実施例2におけるスナバ回路のコンデンサ容量と抵抗値を設定し、外部電極に搭載した場合の電圧波形である。実施例1及び実施例2とも同様な電圧波形であった。 FIG. 21 shows the measurement results of Example 1 and Example 2. The voltage waveform at the location indicated by the arrow in FIG. 20 is measured with an FET probe, and the output voltage of the switching circuit is measured. FIG. 21A is a voltage waveform when the capacitor capacity in the first embodiment and the capacitor capacity and resistance value of the snubber circuit in the second embodiment are set by the simulation means and mounted on the external electrode. The voltage waveform was the same in both Example 1 and Example 2.
 図21(B)は、ノイズを測定しながら外部搭載電子部品の値を調整してノイズを除去した結果を示す電圧波形である。実施例1ではノイズを測定しながらコンデンサ容量を調整し、実施例2におけるスナバ回路では、ノイズを測定しながらコンデンサ容量と抵抗値を調整した。サージ電圧が除去され、高周波リンギングも抑圧された。これにより、本発明の有効性が確認された。 FIG. 21 (B) is a voltage waveform showing the result of removing noise by adjusting the values of externally mounted electronic components while measuring noise. In Example 1, the capacitor capacity was adjusted while measuring noise, and in the snubber circuit in Example 2, the capacitor capacity and resistance value were adjusted while measuring noise. Surge voltage was removed and high frequency ringing was suppressed. This confirmed the effectiveness of the present invention.
 スイッチング電源は様々な形態があるが、本発明のパワーモジュールを備えたスイッチング電源は、DC/DCコンバータによるスイッチング電源やAC/DCコンバータによるスイッチング電源がある。さらには、ユニットに応じた機能パワーモジュールであってもよい。 Although there are various forms of switching power supplies, switching power supplies provided with the power module of the present invention include switching power supplies using DC / DC converters and switching power supplies using AC / DC converters. Furthermore, a functional power module corresponding to the unit may be used.
 図22は、昇圧型の同期整流式DC/DCコンバータの回路例である。同期整流式昇圧DC/DCコンバータは、図6に示した降圧型の同期整流式DC/DCコンバータにおいて、入力と出力を逆にした回路構成である。図22に示したパワーモジュール20-2では、スイッチング回路に接続するコンデンサ22を外部搭載部品として適用している。スイッチング素子をカスコ―ド接続とて、第1スイッチング素子にGaNを使用した場合の同期整流式昇圧DC/DCコンバータ回路である。GaNを使用することで、同期整流式昇圧DC/DCコンバータ回路は、1kV以上の出力電圧DCoutにも対応できる。 FIG. 22 is a circuit example of a step-up type synchronous rectification DC / DC converter. The synchronous rectification step-up DC / DC converter has a circuit configuration in which the input and output are reversed in the step-down synchronous rectification DC / DC converter shown in FIG. In the power module 20-2 shown in FIG. 22, the capacitor 22 connected to the switching circuit is applied as an externally mounted component. This is a synchronous rectification step-up DC / DC converter circuit when the switching element is in cascode connection and GaN is used as the first switching element. The use of GaN, synchronous boost DC / DC converter circuit can cope with 1kV or more output voltage DC out.
 図23は、複数のパワーモジュールを搭載したシステムの例を示す。機能パワーモジュールは、ダイオード、サイリスタやMOSFETなど、パワー半導体を多く採用し、単相・3相ブリッジなどで高効率化が可能なモジュールである。産業機器や自動車市場など幅広い市場に対応している。図23に示した機能パワーモジュールは、自動車向けの機能パワーモジュールであり、スタータジェネレータ、インバータ整流部、DC昇圧部、昇降圧部、インバータ出力部及び双方向インバータ部により構成されている。インバータ整流部に図4で示した三相インバータ回路を利用したパワーモジュール20-4に、また、インバータ出力部に図3で示したスイッチング回路を利用したパワーモジュール20-4に、本発明のパワーモジュールが適用可能である。 FIG. 23 shows an example of a system equipped with a plurality of power modules. Functional power modules are modules that employ many power semiconductors, such as diodes, thyristors, and MOSFETs, and that can achieve high efficiency with single-phase and three-phase bridges. It corresponds to a wide range of markets such as industrial equipment and automobile market. The functional power module shown in FIG. 23 is a functional power module for automobiles, and includes a starter generator, an inverter rectifier, a DC booster, a buck-boost unit, an inverter output unit, and a bidirectional inverter unit. The power module 20-4 using the three-phase inverter circuit shown in FIG. 4 for the inverter rectifier and the power module 20-4 using the switching circuit shown in FIG. Module is applicable.
 以上、本発明の実施形態について説明したが、本発明は、上述した実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲内で様々な変形や応用が可能である。 As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, A various deformation | transformation and application are possible within the range which does not deviate from the summary of this invention.
10 パワーモジュール
12、12-1、12-2 モールドケース
14-1~5 外部電極
16 リード
20、20-1、20-2 パワーモジュール
22 コンデンサ
30、30-1~5 スイッチング回路
32 ハイサイドスイッチング素子
34、34-1、34-2 Hゲート
36、36-1、36-2 Hドレイン
38、38-1、38-2 Hソース
40 ローサイドスイッチング素子
42、42-1、42-2 Lゲート
44、44-1、44-2 Lドレイン
46 Lソース
48 スイッチングダイオード
50 同期整流式降圧DC/DCコンバータの基本回路
52 入力電圧
54 入力コンデンサ
56 ゲートドライブ回路
58 出力インダクタ
60 出力コンデンサ
62 負荷
66 寄生インダクタンスと寄生容量を考慮した等価回路
70-1~5、70-10 寄生インダクタンス
72-1、72-2 等価抵抗
74-1、74-2 寄生容量
76-1、76-2 ボディダイオード
78 浮遊容量
80 ハイサイドパワーMOSFET
82 ローサイドパワーMOSFET
90 保護回路
92、92-1、92-2、92-3 スナバ回路
94 アバランシェダイオード
100 スナバ抵抗
102 スナバコンデンサ
104 スナバダイオード
106 ツェナーダイオード
110 カスコード接続素子
112、112-1、112-2 第1スイッチング素子
114、114-1、114-2 第2スイッチング素子
10 Power module 12, 12-1, 12-2 Mold case 14-1 to 5 External electrode 16 Lead 20, 20-1, 20-2 Power module 22 Capacitor 30, 30-1 to 5 Switching circuit 32 High side switching element 34, 34-1 and 34-2 H gates 36, 36-1, and 36-2 H drains 38, 38-1, and 38-2 H source 40 Low-side switching elements 42, 42-1, and 42-2 L gate 44, 44-1 and 44-2 L drain 46 L source 48 Switching diode 50 Basic circuit 52 of synchronous step-down DC / DC converter 52 Input voltage 54 Input capacitor 56 Gate drive circuit 58 Output inductor 60 Output capacitor 62 Load 66 Parasitic inductance and parasitic Equivalent circuits 70-1 to 70, 70 taking capacity into consideration 10 parasitic inductance 72-1 and 72-2 equivalent resistance 74-1 and 74-2 parasitic capacitance 76-1 and 76-2 body diode 78 stray capacitance 80 high-side power MOSFET
82 Low-side power MOSFET
90 Protection circuit 92, 92-1, 92-2, 92-3 Snubber circuit 94 Avalanche diode 100 Snubber resistor 102 Snubber capacitor 104 Snubber diode 106 Zener diode 110 Cascode connection element 112, 112-1, 112-2 First switching element 114, 114-1, 114-2 Second switching element

Claims (10)

  1.  少なくともスイッチング素子又は整流素子を含むケース内搭載電子部品と、
     前記ケース内搭載電子部品が樹脂封止されたモールドケースと、
     前記モールドケースの外表面に露出した2以上の外部電極と、
     前記ケース内搭載電子部品と前記外部電極を電気的に接続する導電部材又はビアと、
    を備えていることを特徴とするパワーモジュール。
    An in-case electronic component including at least a switching element or a rectifying element;
    A mold case in which the electronic components mounted in the case are sealed with resin;
    Two or more external electrodes exposed on the outer surface of the mold case;
    A conductive member or via that electrically connects the in-case mounted electronic component and the external electrode;
    A power module comprising:
  2.  少なくともスイッチング素子又は整流素子を含むケース内搭載電子部品と、
     前記ケース内搭載電子部品が樹脂封止されたモールドケースと、
     前記モールドケースの外表面に露出した2以上の外部電極と、
     前記ケース内搭載電子部品と外部電極を電気的に接続する導電部材又はビアと、
     前記外部電極に電気的に接続された外部搭載電子部品と、
    を備えていることを特徴とするパワーモジュール。
    An in-case electronic component including at least a switching element or a rectifying element;
    A mold case in which the electronic components mounted in the case are sealed with resin;
    Two or more external electrodes exposed on the outer surface of the mold case;
    A conductive member or via for electrically connecting the in-case mounted electronic component and the external electrode;
    An externally mounted electronic component electrically connected to the external electrode;
    A power module comprising:
  3.  前記外部搭載電子部品は、少なくともコンデンサを含むこと、
    を特徴とする請求項2に記載のパワーモジュール。
    The externally mounted electronic component includes at least a capacitor;
    The power module according to claim 2.
  4.  前記外部搭載電子部品は、スイッチング波形の寄生成分に起因するサージを吸収する保護回路が接続されていること、
    を特徴とする請求項2に記載のパワーモジュール。
    The externally mounted electronic component is connected to a protection circuit that absorbs a surge caused by a parasitic component of the switching waveform,
    The power module according to claim 2.
  5.  前記保護回路は、少なくとも抵抗、ダイオード又はコンデンサのいずれか1つを含むスナバ回路であること、
    を特徴とする請求項4に記載のパワーモジュール。
    The protection circuit is a snubber circuit including at least one of a resistor, a diode or a capacitor;
    The power module according to claim 4.
  6.  前記外部搭載電子部品は、少なくとも半導体素子を含むこと、
    を特徴とする請求項2に記載のパワーモジュール。
    The externally mounted electronic component includes at least a semiconductor element;
    The power module according to claim 2.
  7.  前記半導体素子は、サージ吸収用のアバランシェサージダイオードを含むこと、
    を特徴とする請求項6に記載のパワーモジュール。
    The semiconductor element includes an avalanche surge diode for absorbing surge;
    The power module according to claim 6.
  8.  前記スイッチング素子又は前記整流素子は、ガリウム・ナイトライド、ガリウム・オキサイド又はシリコン・カーバイドから成る素子を含むこと、
    を特徴とする請求項1又は2のいずれか1項に記載のパワーモジュール。
    The switching element or the rectifying element includes an element made of gallium nitride, gallium oxide or silicon carbide;
    The power module according to any one of claims 1 and 2.
  9.  前記スイッチング素子は、ノーマリーオン型半導体とノーマリーオフ型半導体とがカスコード接続されたスイッチング素子であること、
    を特徴とする請求項1又は2のいずれか1項に記載のパワーモジュール。
    The switching element is a switching element in which a normally-on type semiconductor and a normally-off type semiconductor are cascode-connected,
    The power module according to any one of claims 1 and 2.
  10.  請求項1又は2のいずれか1項に記載のパワーモジュールを備えたことを特徴とするスイッチング電源。 A switching power supply comprising the power module according to any one of claims 1 and 2.
PCT/JP2018/006835 2018-02-25 2018-02-25 Power module and switching power supply WO2019163114A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023098822A1 (en) * 2021-12-03 2023-06-08 上海蔚兰动力科技有限公司 High-reliability low-inductance power module packaging structure

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07143733A (en) * 1993-11-16 1995-06-02 Fuji Electric Co Ltd Snubber circuit
JP2004096974A (en) * 2002-09-04 2004-03-25 Yaskawa Electric Corp Snubber module and power converter
JP2013157578A (en) * 2012-02-01 2013-08-15 Mitsubishi Electric Corp Power semiconductor device and manufacturing method of the same
WO2014033857A1 (en) * 2012-08-29 2014-03-06 株式会社安川電機 Power conversion apparatus
WO2015125352A1 (en) * 2014-02-24 2015-08-27 三菱電機株式会社 Power semiconductor module and power unit
JP2017011049A (en) * 2015-06-19 2017-01-12 株式会社日立製作所 Insulation circuit board, and power semiconductor device using the same

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07143733A (en) * 1993-11-16 1995-06-02 Fuji Electric Co Ltd Snubber circuit
JP2004096974A (en) * 2002-09-04 2004-03-25 Yaskawa Electric Corp Snubber module and power converter
JP2013157578A (en) * 2012-02-01 2013-08-15 Mitsubishi Electric Corp Power semiconductor device and manufacturing method of the same
WO2014033857A1 (en) * 2012-08-29 2014-03-06 株式会社安川電機 Power conversion apparatus
WO2015125352A1 (en) * 2014-02-24 2015-08-27 三菱電機株式会社 Power semiconductor module and power unit
JP2017011049A (en) * 2015-06-19 2017-01-12 株式会社日立製作所 Insulation circuit board, and power semiconductor device using the same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023098822A1 (en) * 2021-12-03 2023-06-08 上海蔚兰动力科技有限公司 High-reliability low-inductance power module packaging structure

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