JP2024031344A - Power supply device - Google Patents

Abstract

To make a power supply device operate by applying a heat to a load in order to make the load being stable with a simple structure under a low temperature.SOLUTION: A power supply device comprises: a high-side transistor to which a drain and a source are connected to between a power supply terminal and a middle point terminal; a low-side transistor to which the drain and the source are connected to between the middle point terminal and a ground terminal; a low-pass filter that outputs an output voltage by smoothing a voltage of the middle point terminal; a switching control part that makes the high-side transistor and the low-side transistor switch operate complementary; a liner control part that makes the high-side transistor operates in a liner amplification; a temperature detection element that detects the temperature of the load; and a temperature control part that controls a voltage value of an output voltage so as to set to a target value by the liner control part in the case where the temperature of the load is lower than a first value, and controls the output voltage so as to set to a target value by the switching control part in the case where a temperature of the load is higher than a second value.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power supply device.

Electronic devices are used in various temperature environments. Therefore, various devices included in electronic equipment must operate stably in various temperature environments.

However, some devices exhibit variations in characteristics or large individual differences in a low-temperature environment. For example, in a crystal oscillator, the oscillation frequency fluctuates at temperatures below −35° C., and individual differences in temperature characteristics become large.

In order to solve such problems, for example, a technique is known in which a heater is provided near the crystal oscillator and the crystal oscillator is heated by the heater in a low-temperature environment (Patent Document 1). In addition, for example, in order to avoid errors in data transfer due to instability of the power supply voltage by flowing current to the heater near the crystal oscillator, a technology is known that starts the operation of the heater after data transfer. (Patent Document 2).

JP2010-62868A JP2021-48460A

However, a configuration in which a heater is provided and the heater is operated at low temperatures requires a large number of parts. Furthermore, the operation of the heater may destabilize the operation of surrounding circuits.

SUMMARY OF THE INVENTION An object of the present invention is to provide a power supply device that can supply power to a load and operate the load stably by applying heat to the load with a simple configuration at low temperatures.

In order to solve the above-mentioned problems and achieve the objects, the power supply device according to the present invention is a power supply device that supplies a stabilized DC output voltage to a load, and the power supply device is a power supply device that supplies a stabilized DC output voltage to a load. a high-side transistor whose drain and source are connected to the terminal; a rectifying element connected between the midpoint terminal and a ground terminal to which a ground potential is applied; and a rectifying element that smoothes the voltage at the midpoint terminal. a low-pass filter that supplies the output voltage to an output terminal that outputs the output voltage; a switching control unit that causes the voltage value of the output voltage to approach a preset target value by switching the high-side transistor; a linear control unit that brings the voltage value of the output voltage closer to the target value by linearly amplifying a high-side transistor; a temperature detection element that detects the temperature of the load; and a temperature detection element that detects the temperature of the load; If the temperature of the load is lower than the first value, the function of the switching control section is stopped, the linear control section controls the voltage value of the output voltage to the target value, and the temperature of the load is set to be equal to or higher than the first value. A temperature control section that stops the function of the linear control section and causes the switching control section to control the output voltage to the target value when the temperature is higher than the second set value.

According to the present invention, it is possible to supply power to a load and to stably operate the load by applying heat to the load with a simple configuration at low temperatures.

FIG. 1 is a diagram showing the configuration of an electronic device according to an embodiment. FIG. 2 is a diagram illustrating an example of mounting the electronic device according to the embodiment. FIG. 3 is a flowchart showing the process flow of the temperature control section. FIG. 4 is a diagram showing the configuration of an electronic device according to a first modification. FIG. 5 is a diagram showing an example of mounting an electronic device according to the first modification. FIG. 6 is a diagram showing the configuration of an electronic device according to a second modification.

Hereinafter, an electronic device 10 according to an embodiment will be described in detail with reference to the accompanying drawings. The electronic device 10 according to the embodiment supplies power to the load, and also provides heat to the load with a simple configuration at low temperatures to stably operate the load.

FIG. 1 is a diagram showing the configuration of an electronic device 10 according to an embodiment. The electronic device 10 includes a power supply device 20, a first load 22, and a second load 24.

The power supply device 20 outputs a stabilized DC output voltage to the load. The first load 22 and the second load 24 are examples of loads, and are circuits or devices that operate using the DC voltage output from the power supply device 20 as a power source.

The characteristics of the first load 22 fluctuate or the individual differences in characteristics become large at low temperatures. The first load 22 is, for example, a crystal oscillator. Crystal oscillators experience fluctuations in oscillation frequency and large individual differences in temperature characteristics at temperatures below -35°C. Note that the first load 22 may be a device other than a crystal oscillator, such as a processor whose operation is not stable at low temperatures. Further, the first load 22 may further include a device other than a crystal oscillator, which operates stably even at low temperatures.

The second load 24 operates in cooperation with the first load 22. For example, when the first load 22 is a crystal oscillator, the second load 24 is a circuit that operates based on the clock generated by the first load 22.

Power supply device 20 has an output terminal 26. The output terminal 26 is connected to the first load 22 and the second load 24 and outputs an output voltage.

In this embodiment, each terminal such as the output terminal 26 may be an IC terminal or an electrode pad formed on a substrate as long as it is electrically conductive. Alternatively, it may be simply a part of the wiring.

Further, the power supply device 20 includes a power supply IC (Integrated Circuit) 30, a low-pass filter 32, a high-side voltage dividing resistor 34, a low-side voltage dividing resistor 36, and a temperature detection element 38.

Power supply IC 30 includes a power supply terminal 52, a ground terminal 54, an intermediate terminal 56, a feedback terminal 58, and a temperature detection terminal 60.

The power supply IC 30 performs a switching operation or a linear amplification operation. When performing a switching operation, the power supply IC 30 generates a pulse voltage in which the power supply voltage and the ground potential are alternately switched. Further, when performing a linear amplification operation, the power supply IC 30 generates a DC voltage stabilized at a target value.

The power supply terminal 52 is supplied with a power supply voltage from a DC power source such as a battery or a power converter. The ground terminal 54 is connected to the ground and given a ground potential.

The intermediate terminal 56 outputs a pulse voltage when performing a switching operation. Further, the intermediate terminal 56 outputs a DC voltage when performing a linear amplification operation.

Feedback terminal 58 is connected to a connection point between high-side voltage dividing resistor 34 and low-side voltage dividing resistor 36 connected in series. The temperature detection terminal 60 is connected to the temperature detection element 38.

The low-pass filter 32 is provided between the intermediate terminal 56 and the output terminal 26 of the power supply IC 30. The low-pass filter 32 smoothes the voltage output from the intermediate terminal 56 of the power supply IC 30 and outputs it from the output terminal 26 as an output voltage. Therefore, when the power supply IC 30 is performing a switching operation and outputs a pulse voltage from the intermediate terminal 56, the low-pass filter 32 can smooth the pulse voltage and output it from the output terminal 26 as a DC output voltage. can.

In this embodiment, the low-pass filter 32 includes an inductor 40 and a capacitor 42. Inductor 40 is connected between intermediate terminal 56 and output terminal 26 . Capacitor 42 is connected between output terminal 26 and ground. Inductor 40 and capacitor 42 can smooth the voltage at intermediate terminal 56 and output it from output terminal 26 . Further, the capacitor 42 temporarily supplies and absorbs charge in place of the power supply IC 30 when the response of the current supply from the power supply IC 30 is delayed due to a sudden change in the current consumption of the first load 22 and the second load 24 .

Note that the low-pass filter 32 is not limited to the configuration shown in FIG. 1, and may have any configuration. Furthermore, the low-pass filter 32 may be included inside the power supply IC 30.

High side voltage dividing resistor 34 and low side voltage dividing resistor 36 are connected in series. A high-side voltage dividing resistor 34 and a low-side voltage dividing resistor 36 connected in series are provided between the output terminal 26 and the ground terminal 54. The high side voltage dividing resistor 34 is provided on the output terminal 26 side. The low-side voltage dividing resistor 36 is provided on the ground terminal 54 side. A connection point between the high-side voltage dividing resistor 34 and the low-side voltage dividing resistor 36 is connected to a feedback terminal 58 of the power supply IC 30. Thereby, the power supply IC 30 can detect the voltage value of the output voltage. Note that the high-side voltage dividing resistor 34 and the low-side voltage dividing resistor 36 may be included inside the power supply IC 30.

The temperature detection element 38 is placed near the first load 22 and detects the temperature of the first load 22. The temperature detection element 38 is connected to the temperature detection terminal 60 of the power supply IC 30 and supplies a temperature signal representing the temperature of the first load 22 to the power supply IC 30. For example, the temperature detection element 38 is a diode whose forward current changes depending on the temperature. Note that the temperature detection element 38 is not limited to such a diode, but may be another device or circuit. Further, the temperature detection element 38 may be included inside the power supply IC 30.

Power supply IC 30 includes a high-side transistor 62, a high-side driver 64, a low-side transistor (rectifier) 66, a low-side driver 68, a switching control section 70, a linear control section 72, and a temperature control section 74.

Note that all or some of these components included in the power supply IC 30 do not need to be integrated as an integrated circuit. For example, some of these components included in the power supply IC 30 may be elements separate from the integrated circuit, and may be configured to be connected to the integrated circuit on the substrate.

The drain and source of the high-side transistor 62 are connected between the power supply terminal 52 and the intermediate terminal 56. The high-side transistor 62 is a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). In this embodiment, the high-side transistor 62 is an enhancement type P-MOSFET, and has a source connected to the power supply terminal 52 and a drain connected to the intermediate terminal 56.

The high-side transistor 62 performs a switching operation to switch between a conductive state and a non-conductive state between the drain and source depending on the voltage applied to the gate. Further, the high-side transistor 62 also performs a linear amplification operation in which the amount of current flowing between the drain and the source changes linearly depending on the voltage applied to the gate.

High side driver 64 applies a gate voltage to high side transistor 62. The high side driver 64 receives control from the switching control section 70 or the linear control section 72. When receiving control from the switching control unit 70, the high-side driver 64 causes the high-side transistor 62 to perform a switching operation. Furthermore, when receiving control from the linear control unit 72, the high-side driver 64 causes the high-side transistor 62 to perform a linear amplification operation.

The drain and source of the low-side transistor 66 are connected between the intermediate terminal 56 and the ground terminal 54. The low-side transistor 66 is a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). In this embodiment, the low-side transistor 66 is an enhancement type N-MOSFET, and has a drain connected to the intermediate terminal 56 and a source connected to the ground terminal 54.

The low-side transistor 66 performs a switching operation to switch between a conductive state and a non-conductive state between the drain and source depending on the voltage applied to the gate.

Low side driver 68 applies a gate voltage to low side transistor 66. The low side driver 68 receives control from the switching control section 70 or the linear control section 72. When receiving control from the switching control unit 70, the low-side driver 68 causes the low-side transistor 66 to perform a switching operation. Furthermore, when receiving control from the linear control section 72, the low-side driver 68 causes the low-side transistor 66 to be rendered non-conductive.

The switching control unit 70 acquires the voltage value of the reference voltage, which is the voltage at the connection point between the high-side voltage dividing resistor 34 and the low-side voltage dividing resistor 36. The switching control unit 70 causes the high-side transistor 62 and the low-side transistor 66 to perform complementary switching operations via the high-side driver 64 and the low-side driver 68. That is, the switching control unit 70 alternately turns on each of the high-side transistor 62 and the low-side transistor 66 so that both the high-side transistor 62 and the low-side transistor 66 do not turn on at the same time. Then, the switching control unit 70 controls the ratio of the time during which the high-side transistor 62 is in a conductive state and the time during which the low-side transistor 66 is in a conductive state so that the voltage value of the reference voltage becomes a preset voltage value. Thereby, the switching control unit 70 stably supplies the output voltage of the target value to the first load 22 and the second load 24 even when the current consumption by the first load 22 and the second load 24 changes. be able to.

The linear control unit 72 acquires the voltage value of the reference voltage, which is the voltage at the connection point between the high-side voltage dividing resistor 34 and the low-side voltage dividing resistor 36. The linear control unit 72 makes the low-side transistor 66 non-conductive via the low-side driver 68. Then, the linear control unit 72 performs a linear amplification operation to change the drain-source current of the high-side transistor 62 via the high-side driver 64 so that the voltage value of the reference voltage becomes a preset voltage value. That is, the linear control unit 72 causes the high-side transistor 62 to perform a linear amplification operation, thereby bringing the voltage value of the output voltage close to a preset first target value. Thereby, the linear control unit 72 stably supplies the output voltage of the target value to the first load 22 and the second load 24 even when the current consumption by the first load 22 and the second load 24 changes. be able to.

The temperature control unit 74 acquires a temperature signal representing the temperature of the first load 22 from the temperature detection element 38. The temperature control section 74 causes one of the switching control section 70 and the linear control section 72 to function, and stops the other function, based on the temperature signal. That is, the temperature control unit 74 switches between stabilizing the output voltage by switching control and stabilizing the output voltage by linear amplification control based on the temperature signal.

More specifically, when the temperature of the first load 22 is lower than the first value, the function of the switching control section 70 is stopped, and the linear control section 72 is controlled to set the voltage value of the output voltage to the target value. Further, when the temperature of the first load 22 is higher than a preset second value that is equal to or higher than the first value, the temperature control unit 74 stops the function of the linear control unit 72 and causes the switching control unit 70 to adjust the output voltage to the target value. Control the value.

FIG. 2 is a diagram showing an example of mounting the electronic device 10. As shown in FIG. The electronic device 10 includes, for example, a substrate 82 and a heat conductor plate 84.

Each of the substrate 82 and the thermal conductor plate 84 includes wiring, and semiconductor devices and electronic devices are mounted thereon. The thermal conductor plate 84 is a substrate or a semiconductor layer formed of a material having the same thermal conductivity coefficient. The thermal conductor plate 84 is formed of a material having better thermal conductivity than the substrate 82.

In this embodiment, the second load 24 is provided on the substrate 82. Further, an element group 86 including a low-pass filter 32, a high-side voltage dividing resistor 34, a low-side voltage dividing resistor 36, and the like is also provided on the substrate 82.

On the other hand, the power supply IC 30, the first load 22, and the temperature detection element 38 are provided on the heat conductor plate 84. As a result, the first load 22 receives heat generated by power conversion by the high-side transistor 62 in the power supply IC 30 during linear amplification control, and is heated by the transferred heat. Therefore, the first load 22 can operate stably by transferring heat at low temperatures. Moreover, the temperature detection element 38 has the same temperature as the first load 22, and can detect the temperature of the first load 22 with high accuracy.

Further, the power supply IC 30 may be molded in a package having a heat radiation mechanism such as a heat radiation fin. In this case, the power supply IC 30 is provided with a heat dissipation mechanism on the connection surface side with the heat conductor plate 84. Thereby, the power supply IC 30 can efficiently provide the heat generated by the high-side transistor 62 to the first load 22.

Further, each component included in the power supply IC 30 does not need to be housed in one package. In this case, at least the high-side transistor 62 is provided on the thermal conductor plate 84. Thereby, the high-side transistor 62 can efficiently provide the generated heat to the first load 22.

Note that as long as the first load 22 is mounted in a state where the heat generated by the high-side transistor 62 is transferred, the electronic device 10 does not need to have each member mounted as shown in FIG. . For example, the first load 22 may be arranged in the vicinity of the electronic device 10 within the housing or on the board.

Such an electronic device 10 can heat the first load 22 with heat generated from the high-side transistor 62 during linear amplification control. Furthermore, such electronic device 10 can accurately detect the temperature of first load 22 using temperature detection element 38.

FIG. 3 is a flowchart showing the process flow of the temperature control section 74. For example, the temperature control unit 74 executes processing according to the flow shown in FIG. When the electronic device 10 starts operating, the temperature control unit 74 starts processing from S11.

First, in S11, the temperature control section 74 starts the function of the switching control section 70 and stops the function of the linear control section 72. Thereby, the temperature control section 74 can perform power conversion through switching control.

Subsequently, in S12, the temperature control unit 74 acquires a temperature signal from the temperature detection element 38 and detects the temperature of the first load 22. Subsequently, in S13, the temperature control unit 74 determines whether the temperature of the first load 22 is lower than the first value. The first value is set in advance, and is, for example, a temperature higher by a predetermined margin value than the temperature at which the operation of the first load 22 becomes unstable.

If the temperature of the first load 22 is not lower than the first value (No in S13), the temperature control unit 74 returns the process to S12 and continues through S12 and S13 until the temperature of the first load 22 becomes lower than the first value. Repeat the process. Thereby, when the temperature of the first load 22 is equal to or higher than the first value, the temperature control section 74 can continue to cause the switching control section 70 to function and continue to stop the function of the linear control section 72. As a result, the temperature control section 74 can convert power with high efficiency through switching control.

If the temperature of the first load 22 is lower than the first value (Yes in S13), the temperature control unit 74 advances the process to S14.

In S14, the temperature control section 74 stops the switching control section 70 and starts the function of the linear control section 72. Thereby, the temperature control section 74 can perform power conversion using linear amplification control.

Subsequently, in S15, the temperature control unit 74 acquires a temperature signal from the temperature detection element 38 and detects the temperature of the first load 22. Subsequently, in S16, the temperature control unit 74 determines whether the temperature of the first load 22 is higher than the second value.

The second value is set in advance, and is, for example, the same as the first value or a temperature higher than the first value. If the first value and the second value are the same or very close, the temperature control section 74 may frequently switch between switching control and linear amplification control due to the influence of errors and the like. By making the second value different from the first value by a sufficient margin, the temperature control unit 74 can perform stable power conversion using linear amplification control without frequently switching between switching control and linear amplification control. can.

If the temperature of the first load 22 is not higher than the second value (No in S16), the temperature control unit 74 returns the process to S15 and continues through S15 and S16 until the temperature of the first load 22 becomes higher than the second value. Repeat the process. Thereby, the temperature control unit 74 continues to perform power conversion by linear amplification control until the temperature of the first load 22 becomes higher than the second value after the temperature of the first load 22 becomes lower than the first value.

As a result, the temperature control section 74 can increase the heat generated in the high-side transistor 62 by linearly amplifying the high-side transistor 62, thereby heating the first load 22 even more.

When the temperature of the first load 22 becomes higher than the second value (Yes in S16), the temperature control unit 74 advances the process to S17. In S17, the temperature control section 74 starts the function of the switching control section 70 and stops the function of the linear control section 72. As a result, the temperature control unit 74 can perform power conversion through switching control and increase power conversion efficiency.

Then, the temperature control unit 74 returns the process to S12 and repeats the process from S12.

In the power supply device 20 as described above, when the temperature of the first load 22 becomes lower than the first value, the high-side transistor 62 generates heat by performing linear amplification control. Therefore, when the temperature of the first load 22 becomes lower than the first value, the power supply device 20 increases the thermal energy transferred from the high-side transistor 62 to the first load 22 to increase the temperature of the first load 22. Increase the amount of rise. Thereby, when the temperature of the first load 22 is lower than the first value, the power supply device 20 can change the temperature at which the first load 22 operates more stably in a short time.

Further, after the temperature of the first load 22 becomes higher than the second value, the power supply device 20 stops linear amplification control and performs power conversion using switching control. Thereby, the power supply device 20 can improve power conversion efficiency after the temperature reaches a temperature at which the first load 22 operates stably.

As described above, the power supply device 20 according to the present embodiment can provide stable power to the load by applying heat to the load at low temperatures with a simple configuration without a heater or the like.

Although the power supply IC 30 according to this embodiment has been described as a synchronous rectification type including the low-side transistor 66, it may be a diode rectification type in which the low-side transistor 66 is replaced with a diode (rectifier). In the case of using the diode rectification method, the low side driver 68 becomes unnecessary. Even in this case, the heat generated by the high-side transistor 62 can be applied to the first load 22.

(Modified example)
Hereinafter, a plurality of modified examples of this embodiment will be described. Note that the electronic device 10 according to each modification has substantially the same function and configuration as the electronic device 10 according to the embodiment described with reference to FIGS. 1 to 3, so each component is given the same reference numeral. The differences will be explained below.

FIG. 4 is a diagram showing the configuration of an electronic device 10 according to a first modification.

In the power supply device 20 according to the first modification, the high-side transistor 62 and the low-side transistor 66 are provided inside the package of the power supply IC 30 in the embodiment, but in this modification, the high-side transistor 62 and the low-side transistor 66 is provided outside the power supply IC 30.

Moreover, in this modification, the power supply device 20 further includes a charge pump capacitor 88. Power supply IC 30 further includes a high-side control terminal 90, a low-side control terminal 92, and a high-side drive potential terminal 94. Further, power supply IC 30 further includes a diode 96.

High side control terminal 90 is connected to the gate of high side transistor 62. A control voltage is applied to the high side control terminal 90 from the high side driver 64. Therefore, the power supply IC 30 can apply the control voltage output from the high-side driver 64 to the gate of the high-side transistor 62 via the high-side control terminal 90.

Low-side control terminal 92 is connected to the gate of low-side transistor 66. A control voltage is applied to the low side control terminal 92 from the low side driver 68. Therefore, the power supply IC 30 can apply the control voltage output from the low-side driver 68 to the gate of the low-side transistor 66 via the low-side control terminal 92.

Charge pump capacitor 88 is connected between intermediate terminal 56 and high side drive potential terminal 94. Further, the diode 96 has an anode connected to the power supply terminal 52 and a cathode connected to the high side drive potential terminal 94.

In this modification, the high-side driver 64 is supplied with the potential of the intermediate terminal 56 as a reference potential, and the potential of the high-side drive potential terminal 94 as a drive power supply potential.

Here, in this modification, each of the high-side transistor 62 and the low-side transistor 66 is an enhancement type N-MOSFET. In this modification, the high-side transistor 62 has a drain connected to the power supply terminal 52 and a source connected to the intermediate terminal 56.

In the power supply device 20 having such a configuration, when the low-side transistor 66 is on (conducting state), the intermediate terminal 56 becomes the ground potential, the diode 96 is turned on, and the charge pump capacitor 88 is charged. As a result, the charging voltage of the charge pump capacitor 88 becomes a value obtained by subtracting the forward voltage of the diode 96 from the power supply potential.

Subsequently, when the high-side transistor 62 is on (conductive), the intermediate terminal 56 becomes the power supply potential, and the high-side drive potential terminal 94 becomes the sum of the power supply potential and the charging voltage of the charge pump capacitor 88. . Therefore, even when the high-side transistor 62 is on (conducting state), the high-side driver 64 can apply a gate voltage higher than the threshold voltage between the gate and source of the high-side transistor 62, and the high-side transistor 62 can be maintained on (conducting state).

Generally, P-MOSFETs are more expensive than N-MOSFETs. The power supply device 20 according to this modification is configured without using an expensive P-MOSFET. As a result, the power supply device 20 according to the present modification has a simple configuration without a heater or the like, and can apply heat to the load at low temperatures and supply stable power to the load.

FIG. 5 is a diagram showing an example of mounting the electronic device 10 according to the first modification.

In this modification, the power supply IC 30 and the low-side transistor 66 are provided on the substrate 82. In contrast, the high-side transistor 62 is provided on the thermal conductor plate 84. As a result, in this modification, thermal energy generated by power conversion by the high-side transistor 62 external to the power supply IC 30 is transmitted to the first load 22 during linear amplification control, and the heat energy generated by the power conversion by the high-side transistor 62 It is heated by the heat generated.

Such an electronic device 10 can heat the first load 22 with heat generated from the high-side transistor 62 through power conversion during linear amplification control. Furthermore, such electronic device 10 can accurately detect the temperature of first load 22 using temperature detection element 38.

FIG. 6 is a diagram showing the configuration of an electronic device 10 according to a second modification.

The linear control unit 72 according to the second modification causes the low-side transistor 66 to perform a linear amplification operation so that a predetermined current flows through the low-side transistor 66 instead of making the low-side transistor 66 non-conductive. Note that in FIG. 6, the low-side transistor 66 is pseudo-described as a variable resistor.

The higher the current flowing between the drain and the source of the high-side transistor 62, the more heat it generates. Therefore, it is preferable that the power supply device 20 allows a larger current to flow between the drain and source of the high-side transistor 62 when the temperature of the first load 22 is lower than the first value. However, in the high-side transistor 62, the maximum current that can flow between the drain and the source is determined as the maximum rated current.

Therefore, the linear control unit 72 may control the current obtained by subtracting the maximum load current supplied to the first load 22 and the second load 24 from the maximum rated current to flow through the low-side transistor 66. Thereby, the linear control unit 72 can cause the maximum rated current to flow through the high-side transistor 62 and generate a large amount of heat.

Furthermore, the linear control section 72 may control the current flowing through the low-side transistor 66 based on the temperature signal. For example, the linear control unit 72 controls the current flowing through the low-side transistor 66 so that it increases as the temperature of the first load 22 decreases. Thereby, when the temperature of the first load 22 is low, the linear control section 72 can cause a larger current to flow through the high-side transistor 62 to generate a larger amount of heat. When the temperature of the first load 22 is relatively high, the linear control section 72 can cause a small amount of current to flow through the high-side transistor 62 to increase power conversion efficiency.

Note that the low-side transistor 66 according to the second modification is subjected to linear amplification control, so it generates heat. Therefore, in the power supply device 20 according to the second modification, the low-side transistor 66 as well as the high-side transistor 62 may be provided near the first load 22 or on the heat conductor plate 84.

Although the embodiments according to the present invention have been described above, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements within the scope of the gist at the implementation stage. Moreover, various inventions can be formed by appropriately combining the plurality of components disclosed in the above-described embodiments. For example, some components may be deleted from all the components shown in the embodiments. Further, each of the embodiments and modifications described above can be combined arbitrarily.

10 electronic equipment, 20 power supply device, 22 first load, 24 second load, 26 output terminal, 30 power supply IC, 32 low-pass filter, 34 high-side voltage dividing resistor, 36 low-side voltage dividing resistor, 38 temperature detection element, 40 inductor , 42 capacitor, 52 power supply terminal, 54 ground terminal, 56 intermediate terminal, 58 feedback terminal, 60 temperature detection terminal, 62 high-side transistor, 64 high-side driver, 66 low-side transistor (rectifier), 68 low-side driver, 70 switching control part, 72 linear control part, 74 temperature control part, 82 substrate, 84 thermal conductor plate, 86 element group, 88 charge pump capacitor, 90 high side control terminal, 92 low side control terminal, 94 high side drive potential terminal, 96 diode

Claims (6)

A power supply device that supplies a stabilized DC output voltage to a load,
a high-side transistor whose drain and source are connected between a power supply terminal to which a power supply voltage is applied and a midpoint terminal;
a rectifying element connected between the midpoint terminal and a ground terminal to which a ground potential is applied;
a low-pass filter that smoothes the voltage at the midpoint terminal and supplies the output voltage to an output terminal;
a switching control unit that brings the voltage value of the output voltage closer to a preset target value by causing the high-side transistor to perform a switching operation;
a linear control unit that brings the voltage value of the output voltage closer to the target value by linearly amplifying the high-side transistor;
a temperature detection element that detects the temperature of the load;
When the temperature of the load is lower than a preset first value, the function of the switching control unit is stopped, the linear control unit controls the voltage value of the output voltage to the target value, and the temperature of the load is lower than the first value set in advance. temperature control that stops the function of the linear control section and causes the switching control section to control the output voltage to the target value when the temperature is higher than a preset second value that is greater than or equal to the first value. Department and
A power supply device comprising: The rectifying element is a low-side transistor whose drain and source are connected between the midpoint terminal and the ground terminal,
The power supply device according to claim 1, wherein the high-side transistor and the low-side transistor are operated in a complementary manner. The power supply device according to claim 2, wherein the linear control section brings the voltage value of the output voltage close to the target value by bringing the low-side transistor into a non-conducting state and causing the high-side transistor to perform a linear amplification operation. further comprising a thermal conductor plate that is a substrate or a semiconductor layer formed of a material with the same thermal conductivity coefficient,
The power supply device according to claim 1, wherein the high-side transistor, the load, and the temperature detection element are provided on the thermal conductor plate. The power supply device according to claim 2 , wherein the linear control section controls the current flowing through the low-side transistor so that it increases as the temperature of the load decreases. further comprising a thermal conductor plate that is a substrate or a semiconductor layer formed of a material with the same thermal conductivity coefficient,
The power supply device according to claim 5, wherein the high-side transistor, the low-side transistor, the load, and the temperature detection element are provided on the thermal conductor plate.

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