JP2011176973A - Resonance type switching power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve size reduction, cost reduction, and conversion efficiency improvement by directly connecting the side of a resonance circuit and the side of a rectification smoothing circuit without using a transformer for separation. <P>SOLUTION: An inputted DC voltage or a commercial AC voltage is converted to a high-frequency current by a resonance converter 14, transmitted to a secondary side via balancing capacitors 30, 32, subjected to impedance conversion by an impedance conversion circuit 18, and then converted to a DC output by rectifying the high-frequency current via a double-current rectification circuit 20 for reactance rectification and smoothing. The impedance conversion circuit 18 is an LC series resonance circuit, constitutes a resonance current source when viewed from the double-current rectification circuit 20, and connects a capacitor 38 for diversion to a connecting point of the impedance conversion circuit 18 and the double-current rectification circuit 20 in parallel therewith when the double-current rectification circuit 20 is of a choke-input type. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a transformerless resonant switching power supply device that converts high frequency power from a resonant converter into DC power after impedance conversion.

  Conventionally, as this type of impedance conversion type resonant switching power supply device, for example, there are those shown in FIGS.

  FIG. 12 shows a resonance converter disclosed in Patent Document 1, which includes a DC power supply 306, a switching circuit 302 including a switching element 301, and a control unit 307, and performs LC resonance with a leakage inductance 308 and a distributed capacitor 309 of a primary coil of a transformer 305. A (tank) circuit is configured to increase the load side impedance so that a resonance current can be efficiently generated on the secondary side. In order to realize this, a choke input type rectifying and smoothing circuit including a resonance adjusting capacitor 312, a rectifying circuit 313, a smoothing coil 310, and a smoothing capacitor 314 is used via a transformer 305. Here, since the resonance frequency adjusting capacitor 312 has a small capacity, even if it is added to the secondary side, the resonance operation is hardly affected.

  FIG. 13 shows a resonant switching power supply disclosed in Patent Document 2, in which an MOS transistor Q1, Q2, an insulation transformer T including a primary winding L1 and a secondary winding L2, commutation capacitors C1, C2, diodes D1, D2, and The LC resonance (tank) circuit, which is composed of a smoothing capacitor Co, is separated from the inverter and the rectifier circuit by connecting the resonance capacitor Cr and the resonance coil Lr to the tertiary winding L3 of the transformer T, so as to ensure the resonance operation. I am doing so. As a result, the transmission power can be operated separately for power transmission and resonance power, and even if transmission conversion operation with nonlinear operation is performed, the influence on linear resonance operation can be reduced as much as possible. The conversion efficiency can be improved.

  FIG. 14 shows an immittance converter 307 of Patent Document 3, in which four transistors 321, 322, 323, 324 and a transformer 303 are provided for switching following the DC power source 320, and the transformer 303 having an intermediate tap is provided. Has a primary winding 331 and a secondary winding 332, and a resonance capacitor 372 and a resonance reactor 371 of an immittance converter are connected to the primary winding. Both ends of the secondary winding are subjected to both-wave rectification by diodes 341 and 342, and current is supplied to the welds 361 and 362 through the smoothing reactor 351.

  When such an immittance converter is directly connected to the load, the distortion current of the load affects the current and voltage of the LC resonance (tank) circuit formed by the resonance reactor 371 and the resonance capacitor 372. A transformer 303 is interposed between the circuit and the rectifying / smoothing circuit.

  As described above, in the conventional resonance type switching power supply device, a transformer is used to extract this power from the LC resonance circuit (tank circuit) for temporarily storing the transmission power to the output side, and the resonance circuit and the rectifying / smoothing circuit are provided. Separated to reduce mutual influence. This is not a problem when the matching load is linear such as resistance.

  On the other hand, in the case of a rectifying / smoothing circuit with discontinuous nonlinearity due to a combination of diodes and reactance, or an extremely low impedance load, continuous resonance current and resonance voltage by linear operation are required as a prerequisite for impedance conversion. This is not compatible with the operation of the LC resonance circuit.

  For this reason, the resonant circuit and the rectifying / smoothing circuit are separated by a transformer to minimize the influence of the rectifying side reactance and impedance by the turn ratio, leakage inductance, etc. Continuity is improved, and a decrease in the operation Q of the resonance circuit is suppressed.

  This is not a problem in signal processing or conversion that handles low power, but the loss of rectification efficiency is not a problem, but when the conversion power is several watts to several kilowatts, the loss is large, and a transformer is always required in the past. Yes.

Japanese Patent Laid-Open No. 08-019252 Japanese Patent Laid-Open No. 11-356044 JP 2004-086833 A

  However, in such a conventional resonant switching power supply device, since a separating transformer is provided between the resonant circuit and the rectifying / smoothing circuit, the outer shape becomes large and the cost increases.

  Further, when a direct connection is made without providing a transformer between the LC resonance circuit and the rectifying / smoothing circuit, distortion is superimposed on the resonance current and the resonance voltage, the operation Q of the resonance circuit is lowered, and the impedance conversion action is eliminated. For this reason, the primary side (high frequency supply side) and the secondary side (load side) are mismatched, and the power conversion efficiency is significantly reduced.

  If the LC resonant circuit and the rectifying / smoothing circuit are directly connected, the resonant circuit operation is easily affected by the input power and load power, and a large input voltage is required for the resonant current to begin to flow during startup. In the event of a break or transient load change, there is a problem that the resonance current disappears instantaneously due to the impact, and the coil burnout accident is likely to occur due to destruction of the inverter or heat generation of the resonance circuit.

SUMMARY OF THE INVENTION An object of the present invention is to provide a resonant switching power supply device in which a resonant circuit side and a rectifying / smoothing circuit side are directly connected without using a separating transformer, thereby reducing the size, reducing the cost, and improving the conversion efficiency. .

The present invention provides a transformer-less resonant switching power supply device,
A high-frequency current source that converts the input DC voltage or commercial AC voltage into a high-frequency current and outputs it;
A balanced capacitor that transmits the high-frequency current output from the high-frequency current source to the secondary side;
An impedance conversion circuit for impedance-converting and outputting a high-frequency current input via a balanced capacitor;
A reactance rectifying / smoothing circuit that rectifies the high-frequency current converted and output from the impedance conversion circuit and converts the high-frequency current into a DC output;
With
The impedance conversion circuit is an LC series resonance circuit. When the reactance rectification smoothing circuit is a choke input type when viewed from the reactance rectification smoothing circuit, the impedance conversion circuit and the reactance rectification smoothing circuit are connected to each other. In addition, a shunt capacitor is connected in parallel.

In another embodiment of the resonant switching power supply device according to the present invention, as described above, a high-frequency current source, a balanced capacitor, an impedance conversion circuit, and a reactance rectification smoothing circuit are provided.
The impedance conversion circuit is an LC parallel resonance circuit. When the reactance rectification smoothing circuit is configured as a resonant voltage source as viewed from the reactance rectification smoothing circuit, and the reactance rectification smoothing circuit is a capacitor input type, the impedance conversion circuit is connected to the reactance rectification smoothing circuit at A voltage dividing choke coil is connected in series.

In another embodiment of the resonant switching power supply device according to the present invention, as described above, a high-frequency current source, a balanced capacitor, an impedance conversion circuit, and a reactance rectification smoothing circuit are provided.
The impedance conversion circuit is an LC series resonance circuit in which a pair of inductances having a value that is 1/2 of the conversion required value is balanced in series between the input terminal and the output terminal, and a capacitor is connected in parallel between the input terminals. When a resonant current source is configured as viewed from the reactance rectifying / smoothing circuit, and the reactance rectifying / smoothing circuit is a choke input type, a shunt capacitor is connected in parallel at the connection point between the impedance conversion circuit and the reactance rectifying / smoothing circuit. And

In another embodiment of the resonant switching power supply device according to the present invention, as described above, a high-frequency current source, a balanced capacitor, an impedance conversion circuit, and a reactance rectification smoothing circuit are provided.
The impedance conversion circuit is an LC series resonance circuit in which a pair of capacitors having a value twice the required conversion value is connected in series between a pair of input terminals and an output terminal, and an inductance is connected in parallel between the input terminals. When a resonant current source is configured as viewed from the reactance rectifying / smoothing circuit and the reactance rectifying / smoothing circuit is a choke input type, a shunt capacitor is connected in parallel at the coupling point between the impedance conversion circuit and the reactance rectifying / smoothing circuit. It is characterized by.

Here, the high-frequency current source is a resonant converter.

  According to the resonant switching power supply device of the present invention, when the LC resonant circuit side and the rectifying / smoothing circuit side are directly connected without using a separation transformer, the output form on the resonant circuit side and the input form on the rectifying / smoothing circuit side are used. In addition, if the resonant circuit side is a high-frequency current source and the rectifying and smoothing side is a choke input type, a shunt capacitor for resonant current shunting is connected to the connection point between them, and the resonant circuit side is a high-frequency voltage source and the rectifying and smoothing side is a capacitor input type. For example, the voltage dividing choke coil for dividing the resonant voltage is connected to the connection point between them, so that the shunt capacitor or voltage dividing choke coil viewed from the resonant circuit side interpolates the discontinuous part for the load that performs nonlinear operation. The current and voltage continuity on the resonance circuit side can be maintained and the operation Q can be prevented from being lowered.

  Also on the load side, discontinuous power necessary for the rectifying and smoothing operation can be extracted without difficulty from the resonant circuit side.

  Furthermore, instantaneous changes in rectification impedance due to recovery of the rectifier diode, unstable regions of synchronous rectification switch time, etc. are absorbed by the shunt capacitor or voltage dividing choke coil to prevent noise increase and efficiency reduction. There is also an effect.

In this way, no transformer is required between the resonance circuit side and the rectification circuit side, so that the circuit can be reduced in size and cost. In addition, the resonance operation starts from a low voltage when the power is turned on, and a smooth rise can be achieved. Further, since the resonance operation continues even during the transition, it is possible to prevent the inverter from being destroyed and the abnormal heating of the resonance coil.

Circuit diagram showing a first embodiment of the present invention in which a choke input type rectifying and smoothing side is connected to a high-frequency current source The time chart which showed the current voltage waveform of each part in a 1st embodiment of Drawing 1 Explanatory diagram showing an immittance chart for determining impedance matching with the equivalent circuit of FIG. 1 is a circuit diagram showing a second embodiment of the present invention in which the impedance conversion circuit of FIG. 1 is a balanced circuit. Circuit diagram showing another example of the impedance conversion circuit used in the second embodiment of FIG. 1 is a circuit diagram showing a third embodiment of the present invention in which the full-wave rectifying / smoothing circuit of FIG. 1 is a half-wave rectifying / smoothing circuit. 1 is a circuit diagram showing a fourth embodiment of the present invention in which the shunt capacitor of FIG. A circuit diagram showing a fifth embodiment of the present invention in which a high-frequency voltage source is a capacitor input type and a load side rectifying and smoothing side is connected. Explanatory diagram showing an immittance chart for determining impedance matching with the equivalent circuit of FIG. 8 is a circuit diagram showing a sixth embodiment of the present invention in which the voltage dividing choke coil of FIG. 8 is also used for noise generation prevention. 8 is a circuit diagram showing a seventh embodiment of the present invention in which the voltage doubler rectifying / smoothing circuit of FIG. 8 is a full-wave rectifying / smoothing circuit. Circuit diagram showing a conventional resonant converter described in Patent Document 1 Circuit diagram showing a conventional resonant switching power supply described in Patent Document 2 Circuit diagram showing a conventional immittance conversion circuit described in Patent Document 3

  FIG. 1 is a circuit diagram showing a first embodiment of the present invention in which a choke input type rectifying and smoothing circuit is connected to a high-frequency constant current source. FIG. 2 shows voltage and current waveforms in the circuit shown in FIG. Hereinafter, the operation of the circuit will be described with reference to FIGS.

  The first embodiment shown in FIG. 1 is a resonance type switching power supply suitable for a case where the input voltage is relatively high and the output voltage is low. In this case, for example, DC 200 V is input as the DC power supply 10 and converted to DC 5 V to be loaded. 48.

  The DC power supply 10 inputs an unbalanced / balanced conversion unit using the input coil windings 11 and 12 as an input inductance, and converts it into an AC power supply by the resonance converter 14. The resonant converter 14 is coupled by a balanced coupling circuit 16 and is connected to balancing capacitors 30 and 32 in order to perform insulation coupling with the load side.

In the resonant converter 14, a resonant capacitor 22 and a resonant coil 24 are connected in parallel. A FET (Field Effect Transistor) 26 is connected in series to the resonant coil 24, and a switching operation is performed by turning on and off the gate voltage V _DS of the FET 26. Done.

  The resonant capacitor 22 and the resonant coil 24 have the purpose of smoothing the current voltage waveform including the internal capacitance and parasitic capacitance of the FET 26 itself so as not to overlap with each other and reducing the switching loss. However, the resonant capacitor 22 and the resonant coil 24 are omitted. Even so, the function of the present invention as a high-frequency current source does not change. For this reason, the resonance capacitor 22 and the resonance coil 24 are omitted for explanation of the basic operation, and the resonance converter 14 will be described below as a function of performing a switch operation.

In the resonant converter 14, the FET is turned on / off by a control circuit 28 connected to the gate. When the gate voltage V _GS of the FET26 is turned on, the current I _L from the DC power source 10 is increased in proportion to the time the input coil windings 11 and 12, flows. Further, the current value (inductance accumulated energy) of the input coil is determined by the ON time.

When the gate voltage V _GS of the FET26 is turned off, the input current I _L of the coil windings 11, 12 flows into the balancing capacitor 30, 32, the resonance with the input coil and the balanced capacitor (first resonance) and the half-wave The sine wave becomes the drain-source voltage waveform _Vds .

The resonant half-wave sinusoidal drain-source voltage V _ds flows through the body diode generated in the FET 26, although the input coil current I _L decreases and reverses from positive to negative at the voltage drop timing. Sometimes the drain-source voltage _Vds becomes zero.

This resonance operation is repeated at the switching period, and the current I _L (inductance accumulated energy) of the input coil windings 11 and 12 is transferred to the capacitor 34 of the impedance conversion circuit 18 through the balancing capacitors 30 and 32 and the gate voltage V _{GS of the} FET 26. Is turned off, and the potential of the capacitor 34 is increased (converted to capacitor accumulated energy).

  With the above operation, the DC power source is equivalently converted to an AC power source, and power is transmitted through the balanced capacitor.

The first resonant frequency f _r at this time is, as an inductance component, is determined by the total inductance L _r of the input coil windings 11 and 12, the combined capacitance C _r between the equilibrium binding capacitors 30, 32 as a capacitor of . The combined inductance L _r is obtained by L _r = L ₁ + L ₂ . The combined capacitance C _r is obtained by C _r = C ₃₀ · C ₃₂ / (C ₃₀ + C ₃₂ ). From this, the resonance frequency _fr is
f _r = (1 / 2π) (1 / L _r C _r ) ^1/2
It becomes.

The power supply source impedance viewed from the load side is (| voltage | / | current |) of this resonance circuit at the power transmission timing (FET off), and becomes (L _r / C _r ) ^1/2 .

  The design of the supply source impedance is determined by many factors such as transmission power, frequency, component current / voltage rating, etc., for example, when the primary resonant circuit of a 200V input inverter is designed at 700V / 12A, it becomes 58Ω.

2, (A) is a gate voltage V _GS for switching the FET 26, (B) is a drain-source voltage V _ds , and (C) is an input current to the resonant converter 14, that is, flows in the coils 11 and 12. Current I _L.

Timing of on or off of the gate voltage source voltage V _GS of the FET26 is performed in synchronization with the resonance frequency f _r.

In Figure 1, the output current from the DC power source 10 after passing through the balanced coupling circuit 16 and the resonance Kobata 14, is input to the impedance conversion circuit 18 becomes a sine wave of the second resonant frequency f _m.

  The impedance conversion circuit 18 is a circuit in which a capacitor 34 is connected in parallel and a coil 36 is connected in series. Impedance conversion performs impedance matching between the high frequency power supply on the input side and the load on the output side, and reduces distortion of the resonance waveform to reduce power loss.

The impedance conversion circuit 18 is a circuit in which a capacitor 34 is connected in parallel and a coil 36 is connected in series. Since the impedance conversion circuit 18 has a resonance frequency determined by the capacitance of the capacitor 34 and the inductance of the coil 36, it is also an LC resonance circuit. In this LC resonance circuit, due to inductance and capacitance, current is stored in the input coil windings 11 and 12 when the gate voltage V _GS of the FET 26 in the resonance converter 14 is on, and resonates with the balanced capacitors 30 and 32 when off. However, the secondary side impedance conversion circuit 18 is excited to send power to the double current rectifier circuit 20.

Figure 2 (D) and (E) is a waveform of the waveform and the current I _m of the voltage V _m of the capacitor 34 in the impedance conversion circuit 18.
The second resonance frequency f _m is
f _m = (1 / 2π) (1 / L _m C _m ) ^1/2
It becomes. The voltage V _m and the current I _m are sine waves having a resonance frequency f _m .

  Subsequently, the shunt capacitor 38 is connected in parallel with the impedance conversion circuit 18. Although the impedance conversion circuit 18 may be directly connected to the double current rectifier circuit 20, the current rectifier circuit is generally a non-linear circuit in which a coil or a capacitor and a rectifier diode are combined. For an extremely low impedance load, the resonance current becomes excessive and affects the resonance phenomenon itself, resulting in a decrease in power conversion efficiency due to an increase in distortion wave components.

  In order to prevent a decrease in power conversion efficiency due to these phenomena, a shunt capacitor 38 is inserted. Here, the shunt capacitor 38 has a dynamic characteristic in which the current input value of the choke input type rectification greatly changes at the timing of resonance rectification with respect to the resonance current output of series LC resonance designed for static impedance. Therefore, the purpose of this function is to convert between the static impedance and the dynamic impedance by using a component such as a capacitor that utilizes the property of absorbing and discharging the current. is there.

  In the power supply circuit shown in FIG. 1, the load is a choke input type double current rectifier circuit 20. Therefore, the current waveform distortion is adjusted by the shunt capacitor 38. The shunt capacitor 38 may be appropriately adjusted as a variable capacitor in order to improve efficiency with respect to impedance variation depending on the load.

  In the double current rectifier circuit 20 for supplying power to the load, the load 48 is connected to the midpoint where the choke coils 40 and 42 are connected, and the other terminals connected in series of the choke coils 40 and 42 are connected to the shunt capacitor 38. is doing. On the other hand, the diodes 44 and 46 connected in parallel with the choke coils 40 and 42 are connected to the load 48 from both terminal sides of the shunt capacitor 38, respectively. With this configuration, a double current flows through the load 48 via the diodes 44 and 46. The current is smoothed by the energy stored in the choke coils 40 and 42.

FIG. _2F shows the voltages V _D44 and V _D46 across the diodes 44 and ₄₆ and the currents I _L40 and I _L42 of the choke coils 40 and ₄₂ . The energy lost by the current smoothing action by the energy discharge accumulated in the choke coils 40 and 42 is choked by the voltage applied from the impedance conversion circuit 18 (the voltage obtained by subtracting the voltage of the load 48 from V _D44 and V _D46 ). A constant current flows while being replenished with energy by adding to the coils 40 and ₄₂ and increasing the currents I _L40 and I _L42 again. At the timing when the voltages V _D44 and V _D46 across the diodes 44 and ₄₆ are not generated, the waveform of the load 48 is generated as a flyback voltage in the choke coils 40 and 42.

The currents I _L40 and I _L42 are currents that flow through the choke coils 40 and 42, are superimposed on the load 48, and are twice the current flowing into the rectifier circuit. The voltage applied to the rectifier circuit needs to be twice or more the voltage across the load 48 in order to store energy in the choke coils 40 and 42. From this, the input impedance of the double current rectifier circuit viewed from the power source is expressed as a dynamic impedance that is at least four times the value of the load 48. For example, when the output is 5V60A, the input impedance is 0.34Ω or more.

The control circuit 28 in FIG. 1 detects the voltage or current applied to the load 48 and controls the gate voltage of the FET 26 with a control signal modulated while synchronizing the primary resonance period and the secondary resonance period. Yes. In this case, the primary inverter side resonance frequency f _r, because of the power transmission timed secondary resonant commutation side resonance frequency f _m in the switching operation, no use is the general formula of the premise was consistent with the same resonant frequency, performing static impedance matching input and output immittance chart with cornerstone frequency f _m.

  FIG. 3 shows an immittance chart 220 as a method for obtaining values of the capacitor 34 and the coil 36 in order to perform impedance matching in the equivalent circuit of the power supply circuit of FIG. 1 and the impedance conversion circuit 18.

  The equivalent circuit shown in FIG. 3A excludes the shunt capacitor 38 in the power supply circuit shown in FIG. This is because the shunt capacitor 38 has a function of correcting waveform distortion and is not necessary when considering impedance matching.

In the equivalent circuit shown in FIG. 3A, the high-frequency input unit 50 uses a combined impedance of the DC power source 10, the input coil windings 11 and 12, the resonant converter 14, and the balanced coupling circuit as an equivalent circuit. The power source was an AC power source 200, an equivalent resistance R _i 202, an equivalent inductance L _r 204, and an equivalent capacitance C _r 206 were connected in series to form an equivalent circuit of the high frequency source input unit 50. The impedance conversion circuit unit 52 is similar to the actual circuit configuration, and the capacitor C _m 208 and the inductance L _m 210 are obtained by impedance matching. The load output unit 54 is a combined impedance of the current doubler rectifier circuit and the load, and is a resistor R _o 212.

FIG. 3B is an immittance chart 220. The immittance chart is a chart that can simultaneously represent impedance and admittance on polar coordinates, and is used to obtain circuit constants for impedance matching and the like. Impedance on the immittance chart is plotted as a value obtained by multiplying the angular frequency 2 [pi · f _m due to the resonance frequency f _m. The impedance matching method is as follows.

First, from the equivalent circuit of FIG. 3A, the value of the equivalent resistance R _i on the input side is entered at the intersection 226 between the equal resistance circle 222 and the center line of the immittance chart. Then it moves to the intersection 228 of equal reactance ¥ 224 of equivalent inductance L _m (see arrow 1). Further, it moves counterclockwise by the equivalent capacitance C _m along the equal resistance circle 222 (see arrow 2). This point 232 is the equivalent impedance of the high-frequency input unit 50.
The output load _Ro 212 is an equivalent resistance. Therefore, impedance matching can be achieved by setting the equivalent resistance circle 236 of the output load _Ro 212 and the center line 238 by the equivalent capacitance C _m 208 and equivalent inductance L _m 210 of the impedance conversion circuit unit 52. become.

Equivalent impedance of the RF source input unit 50 is the point 232, because the equivalent capacitance C _m of the impedance converter 52 are connected in parallel, consider an equal conductance circle 230 of equivalent resistance R _i, equal conductance of the equivalent resistance Ri Along the circle 230, the output load _Ro 212 is moved to the intersection 234 with the equal resistance circle 236 (see arrow 3). Next, since the equivalent inductance L _m is connected in series, the equivalent inductance L _m is moved along the equal resistance circle 236 of the output load _Ro 212 to the intersection 238 with the center line (see arrow 4).

Here, the moving distance of the arrow 3 is equivalent capacitance C _m 208, and the moving distance of the arrow 4 is equivalent inductance L _m 210.

Since the equivalent capacitance C _m 208 and the equivalent inductance L _m 210 are values depending on the frequency, the capacitance and inductance actually used are the resonance frequency f _m , the capacitance C = 2π · f _m · C _m , and the inductance L = It is obtained by L _m / (2π · f _m ).

The power supply circuit shown in FIG. 1 is a power supply that realizes an inverter with high power conversion efficiency at a high operating frequency on the order of megahertz, and optimally sets the timing of a resonant half-wave sine wave generated by an input coil and a balanced capacitor. Thus, a switching operation that satisfies the E-class operating conditions is possible. The operating frequency is high, and is a resonance frequency determined by the equivalent capacitance C _m and equivalent inductance L _{m in} the impedance conversion circuit unit 52 from the load output unit side. When the high frequency input unit 50 is viewed, it becomes a capacitive power source. Yes.

  The impedance conversion circuit 18 is for impedance matching between the input and output circuits, and may have other circuit configurations in addition to the circuit shown in FIG.

  FIG. 4 shows an example of another circuit configuration of the impedance conversion circuit. FIG. 4A shows a circuit in which an inductance 60 is connected in parallel and a capacitance 62 is connected in series. Further, (B) is divided and connected to a two-terminal pair circuit by doubling the capacitance C of the capacitance of (A).

  FIG. 5 shows a second embodiment according to the present invention. In the power supply circuit shown in FIG. 1, the coil 36 of the impedance conversion circuit 18 is divided by ½ and the divided coils 36A and 36B are divided. It is a circuit diagram connected to a two-terminal pair circuit.

  The operation of the circuit is the same as that of the power supply circuit shown in FIG. 1, but the coil 36 is divided into two parts and connected in parallel to the two-terminal circuit as coils 36A and 36B. It is effective when the output voltage is high because the common mode noise can be reduced and the leakage current can be reduced by unbalanced and balanced conversion to polar voltages and currents.

  FIG. 6 shows a third embodiment according to the present invention. In the power supply circuit shown in FIG. 5, a half-wave rectifier circuit 21 in which the double-current rectifier circuit 20 that performs full-wave rectification to obtain a double current is half-wave rectified. This is a power circuit. In the half-wave rectifier circuit 21, the diode 68 is connected in parallel to the impedance conversion circuit 18, and the choke coil 70 is connected in series to the load 72. The basic operation principle is the same as that of the power supply circuit shown in FIG. 1, but the smoothing of the output unit is performed by half-wave rectification, and the number of components of the rectification unit is small and a simple circuit can be obtained.

  FIG. 7 shows a fourth embodiment according to the present invention. In the power supply circuit shown in FIG. 5, a capacitor for shunting is connected in parallel with each of the diodes 44 and 46 in the current doubler rectifier circuit 20, so that the shunt capacitor 38A and 38B. The function of the capacitors 36A and 36B for shunting is correction of waveform distortion, and the same function can be obtained even when connected in parallel to the diodes 44 and 46. In this case, there is an effect that the noise removal function can also be used. The shunt capacitors 38A and 38B can be adjusted in accordance with the load 48, and the number of components can be reduced if they are fixed at an optimum capacitance value in consideration of efficiency and noise.

  FIG. 8 shows a fifth embodiment according to the present invention which is suitable for power conversion with a relatively low input voltage and a high output voltage.

  The input-side resonant converter is a push-pull resonant converter 74 that uses a push-pull type, and is coupled to the balanced coupling circuit 76 and connected to the impedance conversion circuit 78. The impedance conversion is a parallel connection circuit of the coil 98 and the capacitor 100.

  The output side is a capacitor input type voltage doubler rectifier circuit 80. In the voltage doubler rectifier circuit 80, the capacitors 104 and 106 are connected in parallel to both terminals of the load 112, and the diodes 108 and 110 are connected to both terminals of the load 112 in directions opposite to each other. Since the voltage doubler rectifier circuit 80 on the load side is a capacitor input type, the voltage dividing choke coil 102 is connected in series. Here, the voltage dividing choke coil 102 has a dynamic characteristic in which a voltage input value of capacitor input type rectification greatly changes at the timing of resonance rectification with respect to a resonance voltage output of parallel LC resonance designed for static impedance. Therefore, the function of converting between the static impedance and the dynamic impedance with the components represented by the choke coil that uses the property of absorbing and releasing such voltage is used for the instantaneous voltage difference between the two. It is the purpose.

  The push-pull resonance converter 74 connects the DC power supply 10 to the middle point of the commutation coil 92 via the resonance coil 88, and the other terminal of the DC power supply 10 uses the two FETs 84 and 86 for switching. Connected to both ends. The commutation coil 92 is connected to the impedance conversion circuit 78 via the balanced coupling capacitors 94 and 96 by the balanced coupling circuit 76.

  The resonance frequency is determined by the push-pull resonance converter 74, and the balanced coupling capacitors 94 and 96 are insulated. The coil 98 and the capacitor 100 connected in parallel by the impedance conversion circuit 78 match the impedance on the input side and the output side, and have the same function as the impedance conversion circuit 18 described in FIG.

  Further, the voltage dividing choke coil 102 is connected in series, and the voltage is smoothed by full-wave rectification in the capacitor input type voltage doubler rectifier circuit 80.

  FIG. 9 is an immittance chart for determining circuit constants for impedance matching by impedance conversion with the equivalent circuit of the power supply circuit of FIG. 8, excluding the voltage dividing choke coil 102.

FIG. 9A shows an equivalent circuit, which includes a high-frequency input unit 114, an impedance conversion circuit unit 116, and a load output unit 118 as an equivalent circuit of a capacitor input type load circuit. The high-frequency input unit 114 has an equivalent inductance L _i 254 and an equivalent capacitance C _i 256 connected in parallel to a series circuit of an AC power source 250 and an equivalent resistance R _i 252 using a resonance frequency as an input source, and an equivalent coupling capacitance C _c 258. Are connected in series.

The impedance conversion circuit unit 116 is the same as the actual circuit shown in FIG. 8 and is a parallel connection of an equivalent inductance L _m 260 and an equivalent capacitance C _m 262. The load output unit 118 has an equivalent resistance R _o 264.

From the equivalent circuit shown in FIG. 9A, the equivalent coupling capacitance C _c , the equivalent inductance L _m of the impedance conversion circuit unit 116, and the equivalent capacitance C _m can be obtained.

FIG. 9B is a Smith chart 280 for impedance matching from the equivalent circuit in FIG. First, the input equivalent resistance R _i is entered at a point 284 on the center line in the Smith chart 280 of FIG.

Since the high-frequency input unit 114 is an equivalent circuit in which circuit elements are connected in parallel, an equal conductance circle 282 is considered. Then, the equivalent inductance L _m is moved along the equal conductance circle 282 to the intersection 288 with the equal susceptance circle 286 (see arrow 1).

Next, it is moved clockwise to the point 290 by the susceptance of the equivalent capacitance C _i connected in parallel (see arrow 2). Equivalent coupling capacitor C _c because the series connection, along the equal resistance circle 298 at point 290 is moved in a counterclockwise direction to move an equal conductance circle 296 by the equivalent output resistance R _o to the intersection 294 of equal resistance circle 292 (arrow 3).

Then, along with equal conductance circle 296 of equivalent output resistor R _o, to 292 point corresponding to the equivalent inductance L _m of the impedance conversion circuit section 78, it is moved in a counterclockwise direction (see arrow 4). Finally, moving the susceptance equivalent of the equivalent capacitance C _m and the output resistance Ro of the point 300 (see arrow 5).

Since impedance matching is thereby realized, the equivalent capacitance C _c is from the capacitance due to the movement of the arrow 3, the equivalent inductance L _m is from the inductance due to the movement of the arrow 4, and the equivalent capacitance C _m is from the capacitance due to the movement of the arrow 5. Can be sought.

Since the coupling capacitor 258 is divided and connected, the divided capacitance is twice the equivalent capacitance C _c .

The implementation value can be obtained from the switching frequency f _SW in the high frequency input source by the same calculation as described in FIG.

  The voltage dividing coil 102 is inserted in order to suppress distortion of the voltage waveform in the impedance-matched circuit state, and the capacity is adjusted according to the load.

  FIG. 10 shows a sixth embodiment. In the circuit of the power supply circuit shown in FIG. 8, the voltage dividing coil 102 is divided into voltage dividing coils 102A and 102B and connected in series to the diodes 108 and 109 in the voltage doubler rectifier circuit 80. is doing. The recovery current in the diodes 108 and 110 is suppressed by the voltage dividing coils 102A and 102B, and the generation of noise is also suppressed.

  FIG. 11 shows a seventh embodiment in which the rectifier circuit for the load 112 in the embodiment shown in FIG. 8 is full-wave rectification. The full-wave rectifier circuit 130 constitutes a bridge circuit in which a circuit portion connecting the diode 132, the load 112, and the diode 138 and a circuit portion connecting the diode 134, the load 112, and the diode 136 in series are arranged in parallel. The voltage resulting from the rectification is smoothed by the capacitor 140 and supplied to the load 112.

In addition, this invention is not limited to said embodiment, This invention contains the appropriate deformation | transformation which does not impair the objective and advantage, Furthermore, the limitation by said embodiment is not received.

10: DC power supply 11, 12: input coil winding 14: resonance converter 16, 76: balanced coupling circuit 18, 78: impedance conversion circuit 20: double current rectification circuit 21: half-wave rectification circuit 22, 90: resonance capacitor 24, 88: Resonant coils 26, 84, 86: FET
28, 82: Control circuits 30, 32, 94, 96: Balance capacitors 36, 36A, 36B, 60, 98: Coils 34, 62, 62A, 62B, 100, 104, 106: Capacitors 38, 38A, 38B: Minutes Diverting capacitors 40, 42, 70: Choke coils 44, 46, 68, 108, 110, 132, 134, 136, 138: Diodes 48, 72, 112: Load 50, 114: High frequency input section 52, 116: Impedance conversion circuit Units 54 and 118: load output unit 74: push-pull resonance converter 80: voltage doubler rectifier circuit 92: commutation coils 102, 102A, 102B: voltage dividing choke coil 130: full-wave rectifier circuit 140: smoothing capacitors 220, 280: immittance chart

Claims (5)

A high-frequency current source that converts the input DC voltage or commercial AC voltage into a high-frequency current and outputs it;
A balanced capacitor that transmits a high-frequency current output from the high-frequency current source to the secondary side;
An impedance conversion circuit for impedance-converting and outputting a high-frequency current input via the balanced capacitor;
A reactance rectifying / smoothing circuit that rectifies a high-frequency current converted and output from the impedance conversion circuit and converts the high-frequency current into a DC output;
With
The impedance conversion circuit is an LC series resonance circuit, and constitutes a resonance current source when viewed from the reactance rectification smoothing circuit. When the reactance rectification smoothing circuit is a choke input type, the impedance conversion circuit and the reactance rectification smoothing circuit A resonance-type switching power supply device, wherein a shunt capacitor is connected in parallel to the connection point.
A high-frequency current source that converts the input DC voltage or commercial AC voltage into a high-frequency current by a converter, and outputs it;
A balanced capacitor that transmits a high-frequency current output from the high-frequency current source to the secondary side;
An impedance conversion circuit for impedance-converting and outputting a high-frequency current input via the balanced capacitor;
A reactance rectifying / smoothing circuit that rectifies a high-frequency current converted and output from the impedance conversion circuit and converts the high-frequency current into a DC output;
With
The impedance conversion circuit is an LC parallel resonance circuit, and constitutes a resonance voltage source when viewed from the reactance rectification smoothing circuit. When the reactance rectification smoothing circuit is a capacitor input type, the impedance conversion circuit and the reactance rectification smoothing circuit A resonance type switching power supply device, wherein a voltage dividing choke coil is connected in series to the coupling point.
A high-frequency current source that converts the input DC voltage or commercial AC voltage into a high-frequency current and outputs it;
A balanced capacitor that transmits a high-frequency current output from the high-frequency current source to the secondary side;
An impedance conversion circuit for impedance-converting and outputting a high-frequency current input via the balanced capacitor;
A reactance rectifying / smoothing circuit that rectifies a high-frequency current converted and output from the impedance conversion circuit and converts the high-frequency current into a DC output;
With
The impedance conversion circuit is an LC series resonance circuit in which a pair of inductances having a value that is half the required conversion value is connected in series between the input terminal and the output terminal, and a capacitor is connected in parallel between the input terminals. When a resonant current source is configured as viewed from the reactance rectifying / smoothing circuit and the reactance rectifying / smoothing circuit is a choke input type, a shunting capacitor is connected in parallel at the coupling point between the impedance conversion circuit and the reactance rectifying / smoothing circuit. A resonance type switching power supply device characterized by being connected.
A high-frequency current source that converts the input DC voltage or commercial AC voltage into a high-frequency current and outputs it;
A balanced capacitor that transmits a high-frequency current output from the high-frequency current source to the secondary side;
An impedance conversion circuit for impedance-converting and outputting a high-frequency current input via the balanced capacitor;
A reactance rectifying / smoothing circuit that rectifies a high-frequency current converted and output from the impedance conversion circuit and converts the high-frequency current into a DC output;
With
The impedance conversion circuit is an LC series resonance circuit in which a pair of capacitors having a value twice the necessary conversion value is connected in series between a pair of input terminals and an output terminal, and an inductance is connected in parallel between the input terminals. Yes, when a resonant current source is configured as viewed from the reactance rectifying / smoothing circuit, and the reactance rectifying / smoothing circuit is a choke input type, a shunt capacitor is connected in parallel at the coupling point between the impedance conversion circuit and the reactance rectifying / smoothing circuit. A resonance type switching power supply device characterized by being connected to.
  5. The resonant switching power supply device according to claim 1, wherein the high-frequency current source is a resonant converter.

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