JP2020178391A - Power supply device - Google Patents

Abstract

To provide a power supply device capable of attaining stabilization of an output voltage even in a case where a power supply voltage to be supplied is varied.SOLUTION: A power supply device A1 is configured to convert a power supply voltage Vin inputted from a DC power source P into an output voltage Vout at a target level. The power supply device A1 comprises: an input terminal Tin to which the power supply voltage Vin is applied; an output terminal Tout to which the output voltage Vout is applied; a first conversion unit 1 which converts an inputted first input voltage V11 into a first output voltage V12; and an auxiliary conversion unit 3 which converts an inputted auxiliary input voltage V31 into an auxiliary output voltage V32. The first conversion unit 1 and the auxiliary conversion unit 3 are connected between the input terminal Ti and the output terminal Tout. For the first conversion unit 1, a first transformation state in which transformation is performed in a first transformation ratio and a second transformation state in which transformation is performed in a second transformation ratio are selectively switched and for the auxiliary conversion unit 3, the transformation ratio is changed while being linked with a change in a voltage level of the auxiliary input voltage V31.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a power supply device that converts a DC voltage into a predetermined level of DC voltage.

In recent years, various electronic devices have been equipped with a power supply device that converts a voltage supplied from a DC power supply into a predetermined voltage. Patent Document 1 discloses a conventional power supply device. The power supply device described in Patent Document 1 includes a switching circuit, an isolation transformer, and a rectifier circuit. The switching circuit includes a plurality of switching elements. The switching circuit converts the power supply voltage (DC voltage) input from the DC power supply into an AC voltage by the switching operation of each switching element. Isolation transformers include magnetically coupled primary and secondary windings. The isolation transformer transforms the AC voltage converted by the switching circuit according to the turns ratio of the primary winding and the secondary winding. The rectifier circuit converts (rectifies) the transformed AC voltage into a DC voltage. The DC voltage rectified by the rectifier circuit is the output voltage of the power supply device.

Japanese Unexamined Patent Publication No. 2000-295844

In the power supply device, the supplied power supply voltage may fluctuate, for example, when the connected DC power supply is replaced or when the operation of the connected DC power supply is unstable. The power supply device is required to stabilize the output voltage even when such fluctuations in the power supply voltage occur.

The present disclosure has been conceived in view of the above circumstances, and an object of the present invention is to provide a power supply device capable of stabilizing the output voltage even when the supplied power supply voltage fluctuates. There is.

The power supply device provided by the present disclosure is a power supply device that converts a power supply voltage input from a DC power supply into a target level output voltage, and has an input terminal to which the power supply voltage is applied and the output voltage to which the output voltage is applied. It is provided with an output terminal, a first conversion unit that converts an input first input voltage into a first output voltage, and an auxiliary conversion unit that converts an input auxiliary input voltage into an auxiliary output voltage. The first conversion unit and the auxiliary conversion unit are connected between the input terminal and the output terminal, and the first conversion unit is a first transformation state and a second transformation that transforms at the first transformation ratio. The second transformation state in which the ratio transforms is selectively switched, and the auxiliary conversion unit is characterized in that the transformation ratio changes in conjunction with a change in the voltage level of the auxiliary input voltage.

According to the power supply device of the present disclosure, it is possible to stabilize the output voltage even when the supplied power supply voltage fluctuates.

It is the schematic which shows the whole structure of the power-source device which concerns on 1st Embodiment. It is a circuit block diagram of the 1st conversion part which concerns on 1st Embodiment. It is a circuit block diagram of the 2nd conversion part which concerns on 1st Embodiment. It is a circuit block diagram of the auxiliary conversion part which concerns on 1st Embodiment. It is a component layout drawing (first surface side of a circuit board) of the power supply device which concerns on 1st Embodiment. It is a component layout diagram (second surface side of a circuit board) of the power supply device which concerns on 1st Embodiment. It is a waveform diagram which shows each drive signal when the switching circuit of the 1st conversion part performs a full bridge operation. It is a figure which shows the current path when the switching circuit of the 1st conversion part performs a full bridge operation. It is a figure which shows the current path when the switching circuit of the 1st conversion part performs a full bridge operation. It is a waveform diagram which shows each drive signal at the time of half-bridge operation of the switching circuit of the 1st conversion part. It is a figure which shows the current path when the switching circuit of the 1st conversion part performs a half-bridge operation. It is a figure which shows the current path when the switching circuit of the 1st conversion part performs a half-bridge operation. It is a figure which shows the current path of the auxiliary conversion part. It is a figure which shows the current path of the auxiliary conversion part. It is a figure which shows the power-source device which concerns on the modification. It is a figure which shows the power-source device which concerns on the modification. It is a figure which shows the isolation transformer (the first conversion part) which concerns on the modification. It is a circuit diagram which shows the auxiliary conversion part (step-up converter) which concerns on a modification. It is a circuit diagram which shows the auxiliary conversion part (lifting pressure type converter) which concerns on a modification. It is a circuit diagram which shows the auxiliary conversion part which concerns on the modification. FIG. 20 is a component layout diagram (first surface side of a circuit board) of a power supply device including an auxiliary conversion unit having a circuit configuration shown in FIG. It is the schematic which shows the whole structure of the power-source device which concerns on 2nd Embodiment.

Preferred embodiments of the power supply device of the present disclosure will be described below with reference to the drawings. The same or similar configurations are designated by the same reference numerals, and the description thereof will be omitted.

In the following description, the transformation ratio of an object A is larger than the transformation ratio of an object B means that the input voltage of an object A and the input voltage of an object B, or the output voltage of an object A. When either one of the output voltage of B is the same, the difference (absolute value) between the input voltage and output voltage of a certain object A is larger than the difference (absolute value) between the input voltage and output voltage of a certain object B. When it is large.

1 to 6 show the power supply device A1 according to the first embodiment. The power supply device A1 includes a pair of input terminals Tin, a pair of output terminals Tout, a first conversion unit 1, a second conversion unit 2, an auxiliary conversion unit 3, and a control unit 4.

First, the overall configuration of the power supply device A1 will be described with reference to FIG. FIG. 1 is a schematic view showing the overall configuration of the power supply device A1. The overall configuration shown in FIG. 1 is an example.

The power supply device A1 is supplied with a power supply voltage Vin from the DC power supply P, and converts the power supply voltage Vin into an output voltage Vout of a predetermined target level. Then, the converted output voltage Vout is supplied to the load LO. The power supply device A1 is a step-down type voltage conversion device. Therefore, the voltage level of the output voltage Vout is smaller than the voltage level of the power supply voltage Vin.

A DC power supply P is connected to the pair of input terminals Tin. The power supply voltage Vin supplied from the DC power supply P is applied between the pair of input terminals Tin. Each input side of the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3 is connected in series to the pair of input terminals Tin. The first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3 are connected in this order from the input terminal Tin on the positive electrode side to the input terminal Tin on the negative electrode side. The power supply voltage Vin applied between the pair of input terminals Tin is the input voltage of the first conversion unit 1 (first input voltage V11), the input voltage of the second conversion unit 2 (second input voltage V21), and the auxiliary conversion unit. The voltage is divided into the input voltage of 3 (auxiliary input voltage V31). That is, Vin = V11 + V21 + V31. The first input voltage V11, the second input voltage V21, and the auxiliary input voltage V31 are each DC.

A load LO is connected to the pair of output terminals Tout. The output voltage Vout of the power supply device A1 is applied between the pair of output terminals Tout. The output sides of the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3 are connected in parallel to the pair of output terminals Tout. The output voltage of the first conversion unit 1 (first output voltage V12), the output voltage of the second conversion unit 2 (second output voltage V22), and the output voltage of the auxiliary conversion unit 3 (auxiliary output voltage V32) are output voltages, respectively. It is the same value as Vout. That is, Vout = V12 = V22 = V32. The first output voltage V12, the second output voltage V22, and the auxiliary output voltage V32 are each direct current.

The first conversion unit 1 converts (lowers or boosts) the first input voltage V11 into the first output voltage V12. The second conversion unit 2 converts (lowers or boosts) the second input voltage V21 into the second output voltage V22. The auxiliary conversion unit 3 converts (steps down or boosts) the auxiliary input voltage V31 into the auxiliary output voltage V32. The control unit 4 controls the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3, respectively.

Next, a detailed configuration of the first conversion unit 1 will be described with reference to FIG. FIG. 2 shows the circuit configuration of the first conversion unit 1. The circuit configuration shown in FIG. 2 is an example. The first conversion unit 1 is composed of, for example, an isolated DC / DC converter. The first conversion unit 1 converts the first input voltage V11 into the first output voltage V12. In the power supply device A1, the first conversion unit 1 steps down the first input voltage V11 to the first output voltage V12. Therefore, the voltage level of the first output voltage V12 is smaller than the voltage level of the first input voltage V11.

As shown in FIG. 2, the first conversion unit 1 includes a pair of input terminals T11a and T11b, a pair of output terminals T12a and T12b, an input capacitor C11, an output capacitor C12, a switching circuit 11, a transformer circuit 12 and a rectifier circuit 13. Includes.

A first input voltage V11 is applied between the pair of input terminals T11a and T11b. The first input voltage V11 is a DC voltage. The input terminal T11a is a terminal on the positive electrode side, and the input terminal T11b is a terminal on the negative electrode side. The input terminal T11a is connected to the input terminal Tin on the positive electrode side. Further, a first output voltage V12 is applied between the pair of output terminals T12a and T12b. The first output voltage V12 is a DC voltage, the output terminal T12a is a terminal on the positive electrode side, and the output terminal T12b is a terminal on the negative electrode side.

As shown in FIG. 2, the input capacitor C11 is arranged between the switching circuit 11 and the pair of input terminals T11a and T11b. One end of the input capacitor C11 is connected to the input terminal T11a on the positive electrode side, and the other end is connected to the input terminal T11b on the negative electrode side. The input capacitor C11 divides the power supply voltage Vin from the DC power supply P to generate the first input voltage V11. The first input voltage V11 is a DC voltage. Further, the input capacitor C11 stabilizes the first input voltage V11. The input capacitor C11 corresponds to the "first input capacitor" described in the claims.

As shown in FIG. 2, the output capacitor C12 is arranged between the rectifier circuit 13 and the pair of output terminals T12a and T12b. One end of the output capacitor C12 is connected to the output terminal T12a on the positive electrode side, and the other end is connected to the output terminal T12b on the negative electrode side. The output capacitor C12 stabilizes the first output voltage V12.

As shown in FIG. 2, the switching circuit 11 includes four switching elements Q11, Q12, Q13, and Q14. The switching circuit 11 converts the first input voltage V11 (DC voltage) into an AC voltage by the switching operation of each switching element Q11 to Q14. The switching operation refers to an operation in which the conduction state and the cutoff state are switched. The switching circuit 11 corresponds to the "first switching circuit" described in the claims.

Each of the four switching elements Q11 to Q14 is composed of, for example, a MOSFET. Each switching element Q11 to Q14 has a drain terminal, a source terminal, and a gate terminal. The constituent materials of the switching elements Q11 to Q14 are Si (silicon), SiC (silicon carbide), GaN (gallium nitride) and the like. However, in order to reduce the on-resistance of each switching element Q11 to Q14, it is preferable to use SiC or GaN as the constituent material rather than Si. The lower the on-resistance, the more the conduction loss of each switching element Q11 to Q14 can be reduced. In particular, the on-resistance of each switching element Q11 to Q14 is preferably 500 mΩ or less.

The four switching elements Q11 to Q14 are fully bridge-connected. Specifically, as shown in FIG. 2, a series circuit (leg) in which the switching element Q11 is the upper arm and the switching element Q12 is the lower arm, and the switching element Q13 is the upper arm and the switching element Q14 is the lower arm in series. The circuit (leg) is bridge-connected.

In the switching element Q11, the drain terminal is connected to the input terminal T11a on the positive electrode side, and the source terminal is connected to the drain terminal of the switching element Q12. In the switching element Q12, the drain terminal is connected to the source terminal of the switching element Q11, and the source terminal is connected to the input terminal T11b on the negative electrode side. In the switching element Q13, the drain terminal is connected to the input terminal T11a on the positive electrode side, and the source terminal is connected to the drain terminal of the switching element Q14. In the switching element Q14, the drain terminal is connected to the source terminal of the switching element Q13, and the source terminal is connected to the input terminal T11b on the negative electrode side.

Parasitic diodes are present in each of the switching elements Q11 to Q14. In the configuration shown in FIG. 2, each arm of the switching circuit 11 is composed of the switching elements Q11 to Q14, but diodes may be connected to the switching elements Q11 to Q14 in antiparallel. , Snubber capacitors may be connected in parallel.

The gate terminals of the switching elements Q11 to Q14 are connected to the control unit 4. A drive signal G11 is input to the switching element Q11 from the control unit 4, and the conduction state and the cutoff state are switched according to the drive signal G11. A drive signal G12 is input to the switching element Q12 from the control unit 4, and the conduction state and the cutoff state are switched according to the drive signal G12. A drive signal G13 is input to the switching element Q13 from the control unit 4, and the conduction state and the cutoff state are switched according to the drive signal G13. A drive signal G14 is input to the switching element Q14 from the control unit 4, and the conduction state and the cutoff state are switched according to the drive signal G14. Each drive signal G11 to G14 is a voltage signal, for example, a square pulse wave in which an on signal and an off signal are alternately switched. When the drive signals G11 to G14 are on signals, the switching elements Q11 to Q14 are in a conductive state (on), and when the drive signals G11 to G14 are off signals, the switching elements Q11 to Q14 are in a cutoff state (off). It becomes. Each switching element Q11 to Q14 corresponds to the "first switching element" described in the claims, and each drive signal G11 to G14 corresponds to the "first drive signal" described in the claims.

The transformer circuit 12 transforms the AC voltage input from the switching circuit 11. The transformer circuit 12 outputs the transformed AC voltage to the rectifier circuit 13. As shown in FIG. 2, the transformer circuit 12 includes an isolation transformer TR1, a resonant reactor Lr1, and a resonant capacitor Cr1.

The isolation transformer TR1 insulates the input side (primary side) of the transformer circuit 12 and the output side (secondary side) of the transformer circuit 12, and transforms the AC voltage input to the primary side from the secondary side. Output. The isolation transformer TR1 includes a primary winding W11 and two secondary windings W12, as shown in FIG. The isolation transformer TR1 corresponds to the "first isolation transformer" described in the claims.

The two secondary windings W12 are connected in parallel. The two secondary windings W12 include the two secondary windings W12a and W12b, respectively. An intermediate tap is connected to each secondary winding W12, and each secondary winding W12 is divided into secondary windings W12a and W12b by the intermediate tap. The intermediate tap connected to each secondary winding W12 is connected to the output terminal T12b. The secondary windings W12a and W12b may have different windings connected in series.

The primary winding W11 and each secondary winding W12 (W12a, W12b) are magnetically coupled to each other. The isolation transformer TR1 performs transformation according to the turns ratio of the primary winding W11 and the secondary windings W12a and W12b, respectively. Assuming that the number of turns of the primary winding W11 is n11 and the number of turns of each of the secondary windings W12a and W12b is n12, the above-mentioned winding number ratio is n11: n12. The number of turns of each of the secondary windings W12a and W12b is the same. At this time, the ratio of the voltage level applied to the primary winding W11 to the voltage level applied to the secondary windings W12a and W12b (hereinafter referred to as "transformation ratio of the isolation transformer TR1") is n11 :. It is n12. That is, the voltage level applied to each of the secondary windings W12a and W12b is n12 / n11 times the voltage level applied to the primary winding W11. Therefore, the AC voltage input to the isolation transformer TR1 is transformed by n12 / n11 times and output from the isolation transformer TR1. Therefore, when the number of turns n11 of the primary winding W11 is larger than the number of turns n12 of the secondary windings W12a and W12b, the isolation transformer TR1 steps down, and when the number of turns n11 is less than the number of turns n12, the isolation transformer TR1 Boosts. In the present embodiment, the isolation transformer TR1 has the number of turns n11 of the primary winding W11 larger than the number of turns n12 of the secondary windings W12a and W12b, respectively, and steps down the input voltage to output.

One end of the resonance reactor Lr1 is connected to the connection point between the switching element Q13 and the switching element Q14, and the other end is connected to one end of the primary winding W11. One end of the resonance capacitor Cr1 is connected to the connection point between the switching element Q11 and the switching element Q12, and the other end is connected to the other end of the primary winding W11. The LLC resonance circuit is composed of the resonance reactor Lr1, the resonance capacitor Cr1, and the primary winding W11 of the isolation transformer TR1. The LLC resonance circuit adjusts the resonance frequency and the like to improve the transmission efficiency between the primary winding W11 and each secondary winding W12.

As shown in FIG. 2, the rectifier circuit 13 includes two switching elements Q15 and two switching elements Q16. The rectifier circuit 13 converts (rectifies) the AC voltage input from the transformer circuit 12 into a DC voltage by the switching operation of the switching elements Q15 and Q16. A rectifier diode may be used instead of the switching elements Q15 and Q16. The rectifier circuit 13 is a full-wave rectifier type. The DC voltage rectified by the rectifier circuit 13 corresponds to the first output voltage V12. The rectifier circuit 13 corresponds to the "first rectifier circuit" described in the claims, and the switching elements Q15 and Q16 correspond to the "rectifying switching elements" described in the claims, respectively.

The two switching elements Q15 and the two switching elements Q16 each consist of, for example, a MOSFET. Each of the switching elements Q15 and Q16 has a drain terminal, a source terminal, and a gate terminal. Each constituent material of the two switching elements Q15 and the two switching elements Q16 is Si, SiC, GaN, or the like. However, in order to reduce the on-resistance of each of the switching elements Q15 and Q16, it is preferable to use SiC or GaN as the constituent material rather than Si. The smaller the on-resistance, the more the conduction loss during the switching operation of each of the switching elements Q15 and Q16 can be reduced. In particular, the on-resistance of each of the switching elements Q15 and Q16 is preferably 200 mΩ or less, for example.

As shown in FIG. 2, each switching element Q15 is connected between one end of each secondary winding W12a and the output terminal T12a. Each switching element Q15 is connected between one end of each secondary winding W12b and the output terminal T12b.

The gate terminals of the switching elements Q15 and Q16 are connected to the control unit 4. Each drive signal G15 is input to each switching element Q15 from the control unit 4, and the conduction state and the cutoff state are switched according to the drive signal G15. Each drive signal G16 is input to each switching element Q16 from the control unit 4, and the conduction state and the cutoff state are switched according to the drive signal G16. The drive signals G15 and G16 are voltage signals, for example, square pulse waves in which an on signal and an off signal are alternately switched. When the drive signals G15 and G16 are on signals, the switching elements Q15 and Q16 are in a conductive state (on), and when the drive signals G15 and G16 are off signals, the switching elements Q15 and Q16 are in a cutoff state (off). It becomes.

The first conversion unit 1 is configured as described above, and converts the first input voltage V11 into the first output voltage V12 of a predetermined voltage level by the switching operation of the switching elements Q11 to Q14 and the isolation transformer TR1. Further, the first conversion unit 1 switches between a state in which the switching circuit 11 operates as a full bridge inverter and a state in which the switching circuit 11 operates as a half bridge inverter by the switching operation of each of the switching elements Q11 to Q14. In the following, the state of operating as a full-bridge inverter is referred to as "full-bridge operation", and the state of operating as a half-bridge inverter is referred to as "half-bridge operation". Details of the full bridge operation and the half bridge operation will be described later.

Next, a detailed configuration of the second conversion unit 2 will be described with reference to FIG. The second conversion unit 2 is composed of, for example, an isolated DC / DC converter. The second conversion unit 2 converts the second input voltage V21 into the second output voltage V22. In the power supply device A1, the second conversion unit 2 steps down the second input voltage V21 to the second output voltage V22. Therefore, the voltage level of the second output voltage V22 is smaller than the voltage level of the second input voltage V21.

The second conversion unit 2 is configured in the same manner as the first conversion unit 1. As shown in FIG. 3, the second conversion unit 2 includes a pair of input terminals T21a and T21b, a pair of output terminals T22a and T22b, an input capacitor C21, an output capacitor C22, a switching circuit 21, a transformer circuit 22 and a rectifier circuit 23. Includes. These are configured in the same manner as the pair of input terminals T11a, T11b, the pair of output terminals T12a, T12b, the input capacitor C11, the output capacitor C12, the switching circuit 11, the transformer circuit 12, and the rectifier circuit 13 in the first conversion unit 1, respectively. ing. The input terminal T21a is connected to the input terminal T11b. The input capacitor C21 corresponds to the "second input capacitor" described in the claims.

As shown in FIG. 3, the switching circuit 21 includes four switching elements Q21 to Q24. Each switching element Q21 to 24 corresponds to each switching element Q11 to Q14 of the first conversion unit 1. Each of the switching elements Q21 to Q24 receives each drive signal G21 to G24 from the control unit 4, and performs a switching operation according to each of the drive signals G21 to G24. The switching circuit 21 corresponds to the "second switching circuit" described in the claims. Further, each switching element Q21 to 24 corresponds to the "second switching element" described in the claims, and each drive signal G21 to G24 corresponds to the "second drive signal" described in the claims. To do.

As shown in FIG. 3, the transformer circuit 22 includes an isolation transformer TR2, a resonance reactor Lr2, and a resonance capacitor Cr2. The isolation transformer TR2, the resonance reactor Lr2, and the resonance capacitor Cr2 correspond to the isolation transformer TR1, the resonance reactor Lr1 and the resonance capacitor Cr1 of the first conversion unit 1, respectively. Further, the isolation transformer TR2 includes a primary winding W21 and two secondary windings W22. The primary winding W21 corresponds to the primary winding W11 of the isolation transformer TR1, and each secondary winding W22 (W22a, W22b) corresponds to each secondary winding W12 (W12a, W12b) of the isolation transformer TR1. .. The transformation ratio of the isolation transformer TR1 and the transformation ratio of the isolation transformer TR2 may be the same or different. In the power supply device A1, the transformation ratio of the isolation transformer TR2 is larger than the transformation ratio of the isolation transformer TR1. In the present embodiment, the isolation transformer TR2 has a number of turns n21 of the primary winding W21 larger than the number of turns n22 of each of the secondary windings W22a and W22b, and outputs the input voltage by stepping down. The isolation transformer TR2 corresponds to the "second isolation transformer" described in the claims.

As shown in FIG. 3, the rectifier circuit 23 includes a plurality of switching elements Q25 and Q26. Each switching element Q25 corresponds to each switching element Q15, and each switching element Q26 corresponds to each switching element Q16. Each of the switching elements Q25 and Q26 receives the drive signals G25 and G26 from the control unit 4, and performs a switching operation according to the drive signals G25 and G26. The rectifier circuit 23 corresponds to the "second rectifier circuit" described in the claims, and the switching elements Q25 and Q26 correspond to the "rectifying switching elements" described in the claims, respectively.

The second conversion unit 2 converts the second input voltage V21 into the second output voltage V22 of a predetermined voltage level by the switching operation of each switching element Q21 to Q24 and the isolation transformer TR2. Further, in the second conversion unit 2, the switching circuit 21 operates in full bridge operation and the switching circuit 21 operates in half bridge operation in the same manner as in the first conversion unit 1 due to the switching operation of each switching element Q11 to Q14. Then, it switches.

Next, a detailed configuration of the auxiliary conversion unit 3 will be described with reference to FIG. FIG. 4 shows the circuit configuration of the auxiliary conversion unit 3. The circuit configuration shown in FIG. 4 is an example. The auxiliary conversion unit 3 is composed of, for example, a non-isolated DC / DC converter. The auxiliary conversion unit 3 converts the auxiliary input voltage V31 into the auxiliary output voltage V32. In the power supply device A1, the auxiliary conversion unit 3 steps down the auxiliary input voltage V31 to the auxiliary output voltage V32. Therefore, the voltage level of the auxiliary output voltage V32 is smaller than the voltage level of the auxiliary input voltage V31.

As shown in FIG. 4, the auxiliary conversion unit 3 includes a pair of input terminals T31a and T31b, a pair of output terminals T32a and T32b, an input capacitor C31, an output capacitor C32, a switching circuit 31, and a reactor Lr31.

An auxiliary input voltage V31 is applied between the pair of input terminals T31a and T31b. The auxiliary input voltage V31 is a DC voltage. The input terminal T31a is a terminal on the positive electrode side, and the input terminal T31b is a terminal on the negative electrode side. The input terminal T31a is connected to the input terminal T21b, and the input terminal T31b is connected to the input terminal Tin on the negative electrode side. Further, an auxiliary output voltage V32 is applied between the pair of output terminals T32a and T32b. The auxiliary output voltage V32 is a DC voltage, the output terminal T32a is a terminal on the positive electrode side, and the output terminal T32b is a terminal on the negative electrode side.

As shown in FIG. 4, the input capacitor C31 is arranged between the switching circuit 31 and the pair of input terminals T31a and T31b. One end of the input capacitor C31 is connected to the input terminal T31a on the positive electrode side, and the other end is connected to the input terminal T31b on the negative electrode side. The input capacitor C31 divides the power supply voltage Vin from the DC power supply P to generate an auxiliary input voltage V31. The input capacitor C31 stabilizes the auxiliary input voltage V31. The input capacitor C31 corresponds to the "auxiliary input capacitor" described in the claims.

As shown in FIG. 4, one end of the output capacitor C32 is connected to the output terminal T32a on the positive electrode side, and the other end is connected to the output terminal T32b on the negative electrode side. The output capacitor C32 stabilizes the auxiliary output voltage V32.

As shown in FIG. 4, the switching circuit 31 includes two switching elements Q31 and Q32.

The two switching elements Q31 and Q32 each consist of, for example, a MOSFET. Each of the switching elements Q31 and Q32 has a drain terminal, a source terminal, and a gate terminal. The constituent materials of the switching elements Q31 and Q32 are Si, SiC, GaN and the like. However, in order to reduce the on-resistance of each of the switching elements Q31 and Q32, it is preferable to use SiC or GaN as the constituent material rather than Si. The smaller the on-resistance, the more the conduction loss of each of the switching elements Q31 and Q32 can be reduced.

As shown in FIG. 4, the switching element Q31 and the switching element Q32 are connected in series. The drain terminal of the switching element Q31 is connected to the input terminal T31a on the positive electrode side, the source terminal of the switching element Q31 and the drain terminal of the switching element Q32 are connected, and the source terminal of the switching element Q32 is the input terminal T31b on the negative electrode side. It is connected to the.

The gate terminals of the switching elements Q31 and Q32 are connected to the control unit 4. A drive signal G31 is input to the switching element Q31 from the control unit 4, and the conduction state and the cutoff state are switched according to the drive signal G31. A drive signal G32 is input to the switching element Q32 from the control unit 4, and the conduction state and the cutoff state are switched according to the drive signal G32. Each of the drive signals G31 and G32 is a voltage signal, and is, for example, a square pulse wave in which an on signal and an off signal are alternately switched. When the drive signals G31 and G32 are on signals, the switching elements Q31 and Q32 are in a conductive state (on), and when the drive signals G31 and G32 are off signals, the switching elements Q31 and Q32 are in a cutoff state (off). It becomes. The switching elements Q31 and Q32 correspond to the "auxiliary switching elements" described in the claims, and the drive signals G31 and G32 correspond to the "auxiliary drive signals" described in the claims.

The configuration of the switching circuit 31 is not limited to the above configuration. For example, a diode (for example, a Schottky barrier diode) may be connected to the switching element Q32 in antiparallel. Specifically, the cathode terminal of the diode is connected to the drain terminal of the switching element Q32, and the anode terminal of the diode is connected to the source terminal of the switching element Q32. The diode is used, for example, to reduce conduction loss during dead time, or to suppress voltage fluctuations when using bootstrap. Further, the switching circuit 31 may include a plurality of switching elements Q32 connected in parallel to each other instead of one switching element Q32. In this case, since the amount of current flowing through each switching element Q32 can be reduced, the conduction loss in the switching circuit 31 (auxiliary conversion unit 3) can be reduced. Similarly, the switching element Q31 may include a plurality of switching elements Q31 instead of one.

As shown in FIG. 4, one end of the reactor Lr31 is connected to the connection point between the switching element Q31 and the switching element Q32, and the other end is connected to the output terminal T32a on the positive electrode side.

The auxiliary conversion unit 3 is configured as described above, and converts the auxiliary input voltage V31 into an auxiliary output voltage V32 having a predetermined voltage level by the switching operation of the switching elements Q31 and Q32.

The control unit 4 controls the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3, respectively. The control unit 4 is composed of an integrated circuit (IC) including, for example, a CPU and a memory.

The control unit 4 controls the first conversion unit 1 by generating a plurality of drive signals G11 to G16 and inputting them to the first conversion unit 1. Specifically, the control unit 4 generates the drive signals G11 to G16, and inputs the generated drive signals G11 to G16 to the switching elements Q11 to Q16, respectively. Thereby, the switching operation of each switching element Q11 to Q16 is controlled. In the present embodiment, the control unit 4 controls the switching operation of each switching element Q11 to Q14 by soft switching. The soft switching may be ZVS (Zero Voltage Switching) or ZCS (Zero Current Switching). Each drive signal G11 to G16 is a voltage signal, and is a square pulse wave in which an on signal and an off signal are alternately switched. The duty ratio of each drive signal G11 to G16 is fixed (for example, 50%), and the frequency is also fixed.

The control unit 4 controls the second conversion unit 2 by generating a plurality of drive signals G21 to G26 and inputting them to the second conversion unit 2. Specifically, the control unit 4 generates each drive signal G21 to G26, and inputs each of the generated drive signals G21 to G26 to the switching elements Q21 to Q26, respectively. Thereby, the switching operation of each switching element Q21 to Q26 is controlled. In the present embodiment, the control unit 4 controls the switching operation of each switching element Q21 to Q24 by soft switching. The soft switching may be ZVS or ZCS. Each drive signal G21 to G26 is a voltage signal, and is a square pulse wave in which an on signal and an off signal are alternately switched. The duty ratio of each drive signal G21 to G26 is fixed (for example, 50%), and the frequency is also fixed.

The control unit 4 controls the auxiliary conversion unit 3 by generating a plurality of drive signals G31 and G32 and inputting them to the auxiliary conversion unit 3. Specifically, the control unit 4 generates drive signals G31 and G32, and inputs the generated drive signals G31 and G32 to the switching elements Q31 and G32, respectively. Thereby, the switching operation of each of the switching elements Q31 and Q32 is controlled. In the present embodiment, the control unit 4 controls the switching operation of each of the switching elements Q31 and Q32 by hard switching. Each of the drive signals G31 and G32 is a voltage signal, and is a square pulse wave in which an on signal and an off signal are alternately switched. The drive signal G31 and the drive signal G32 are signals that are inverted from each other. The duty ratio of each of the drive signals G31 and G32 is variable. The duty ratio is appropriately set according to the transformation ratio of the auxiliary conversion unit 3. For example, increasing the duty ratio of the drive signal G31 reduces the transformation ratio (step-down ratio), and decreasing the duty ratio of the drive signal G31 increases the transformation ratio (step-down ratio).

Next, a mounting example of each electronic component of the power supply device A1 will be described with reference to FIGS. 5 and 6. 5 and 6 are component layout diagrams when the power supply device A1 is mounted on the circuit board CB1. FIG. 5 shows the first surface side of the circuit board CB1, and FIG. 6 shows the second surface side of the circuit board CB1. The first surface and the second surface are separated from each other in the thickness direction of the circuit board CB1, the first surface faces one side in the thickness direction, and the second surface faces the other side in the thickness direction. In FIGS. 5 and 6, only some electronic components of the power supply device A1 are shown, and other electronic components are omitted.

The circuit board CB1 is, for example, a printed circuit board of a double-sided board or a multilayer board. The circuit board CB1 has a rectangular shape in a plan view as shown in FIGS. 5 and 6. The plan view shape of the circuit board CB1 is not limited to a rectangle, and may take various shapes such as a square, a polygon, a circle, and an ellipse. In the following, the direction in which the long side of the circuit board CB1 extends is referred to as the longitudinal direction, and the direction in which the short side of the circuit board CB1 extends is referred to as the lateral direction. A wiring pattern is formed on the circuit board CB1. The illustration of the wiring pattern is omitted. According to the wiring pattern, a plurality of electronic components mounted on the circuit board CB1 are connected so as to have the circuit configuration shown in FIGS. 1 to 4.

As shown in FIG. 5, the isolation transformer TR1 is arranged substantially in the center of the first surface of the circuit board CB1. Further, as shown in FIG. 6, the isolation transformer TR2 is arranged substantially in the center of the second surface of the circuit board CB1. Each electronic component on the primary side of the first conversion unit 1 and each electronic component on the primary side of the second conversion unit 2 are arranged on one side in the longitudinal direction with respect to the isolation transformers TR1 and TR2, and the first conversion Each electronic component on the secondary side of the unit 1 and each electronic component on the secondary side of the second conversion unit 2 are arranged on the other side in the longitudinal direction with respect to the isolation transformers TR1 and TR2. In the longitudinal direction, each electronic component on the primary side of the first conversion unit 1 and each electronic component on the secondary side of the first conversion unit 1 are arranged on opposite sides of the isolation transformers TR1 and TR2. , Each electronic component on the primary side of the second conversion unit 2 and each electronic component on the secondary side of the second conversion unit 2 are arranged on opposite sides.

The four switching elements Q11 to Q14 and the four switching elements Q21 to Q24 are arranged in a matrix as shown in FIG. 5, respectively. It should be noted that these may not be arranged in a matrix. Further, as shown in FIG. 5, the four switching elements Q11 to Q14 and the four switching elements Q21 to Q24 are arranged together next to the isolation transformer TR1 in the longitudinal direction. The four switching elements Q11 to Q14 and the four switching elements Q21 to Q24 are arranged in this order in the lateral direction.

As shown in FIG. 6, the switching element Q31 is arranged between the input capacitor C31 and the isolation transformer TR2 in the longitudinal direction. As shown in FIG. 5, the switching element Q32 is arranged next to the isolation transformer TR1 in the longitudinal direction. The switching element Q32 is arranged on one side of the four switching elements Q21 to Q24 (the side opposite to the side on which the four switching elements Q11 to Q14 are arranged) in the lateral direction. As shown in FIG. 6, the reactor Lr31 is arranged between the input capacitor C31 and the isolation transformer TR2 in the longitudinal direction. In FIG. 6, the reactor Lr31 and the switching element Q31 are arranged in the lateral direction, but they may be arranged in the longitudinal direction.

As shown in FIG. 5, the two switching elements Q15 and the two switching elements Q16 are arranged next to the isolation transformer TR1. The two switching elements Q15 and the two switching elements Q16 are arranged in the lateral direction. Further, the two switching elements Q25 and the two switching elements Q26 are arranged next to the isolation transformer TR2 as shown in FIG. The two switching elements Q25 and the two switching elements Q26 are arranged in the lateral direction.

As shown in FIGS. 5 and 6, each switching element Q15, Q16, Q25, Q26 is larger than each switching element Q11 to Q14, Q21 to Q24, Q31, Q32. In the power supply device A1, the secondary side of each isolation transformer TR1 and TR2 has a relatively larger current than the primary side of each isolation transformer TR1 and TR2. Therefore, the switching elements Q15, Q16, Q25, and Q26 are larger than the switching elements Q11 to Q14, Q21 to Q24, Q31, and Q32 by using electronic components that can withstand a large current. The switching elements Q15, Q16, Q25, and Q26 may be smaller than or the same as the switching elements Q11 to Q14, Q21 to Q24, Q31, and Q32.

As shown in FIG. 5, the input capacitor C11 is arranged on one side of each switching element Q11 to Q14 (the side opposite to the side on which the isolation transformer TR1 is arranged) in the longitudinal direction. The input capacitor C21 is arranged on one side of each switching element Q21 to Q24 (the side opposite to the side on which the isolation transformer TR1 is arranged) in the longitudinal direction.

As shown in FIGS. 5 and 6, the input capacitor C31 is composed of two electronic components. The input capacitor C31 having the circuit configuration shown in FIG. 4 is shown as a combined capacitance of the two electronic components. One input capacitor C31 is arranged on the first surface of the circuit board CB1, and the other input capacitor C31 is arranged on the second surface of the circuit board CB1. As shown in FIG. 5, the input capacitor C31 arranged on the first surface of the circuit board CB1 is arranged on one side of the switching element Q32 (the side opposite to the side on which the isolation transformer TR1 is arranged) in the longitudinal direction. There is. As shown in FIG. 6, the input capacitor C31 arranged on the second surface of the circuit board CB1 is located on one side of the switching element Q31 and the reactor Lr31 (the side opposite to the side on which the isolation transformer TR2 is arranged) in the longitudinal direction. Have been placed.

As shown in FIG. 6, the control unit 4 (IC) is arranged next to the isolation transformer TR2 in the longitudinal direction and next to the input capacitor C31 and the switching element Q31 in the lateral direction.

As shown in FIG. 5, the output capacitor C12 is composed of two electronic components. The output capacitor C12 having the circuit configuration shown in FIG. 2 is shown as a combined capacitance of the two electronic components. Both of the two output capacitors C12 are arranged on the first surface of the circuit board CB1. Both of the two output capacitors C12 are arranged on one side of the switching elements Q15 and Q16 (the side opposite to the side on which the isolation transformer TR1 is arranged) in the longitudinal direction. The two output capacitors C12 are arranged in the lateral direction.

As shown in FIG. 6, the output capacitor C22 is composed of two electronic components. The output capacitor C22 having the circuit configuration shown in FIG. 3 is shown as a combined capacitance of the two electronic components. Both of the two output capacitors C22 are arranged on the second surface of the circuit board CB1. Both of the two output capacitors C22 are arranged on one side of the switching elements Q25 and Q26 (the side opposite to the side on which the isolation transformer TR2 is arranged) in the longitudinal direction. The two output capacitors C22 are arranged in the lateral direction.

As shown in FIG. 5, the output capacitor C32 is arranged next to the two output capacitors C12 in the lateral direction. Both the output capacitors C32 are arranged on one side of the switching elements Q15 and Q16 (the side opposite to the side on which the isolation transformer TR1 is arranged) in the longitudinal direction.

The component layout shown in FIGS. 5 and 6 is an example, and the arrangement, size, and number of a plurality of electronic components are not limited to the illustrated configuration. For example, the reactor Lr31 and the two switching elements Q31 and Q32 may all be arranged on either the first surface or the second surface of the circuit board CB1. Further, the reactor Lr31 and the two switching elements Q31 and Q32 may all be arranged on the same side as the output capacitor C32 from the isolation transformers TR1 and TR2 in the longitudinal direction. In this way, by arranging the reactor Lr31 and the two switching elements Q31 and Q32 all on the same side as the output capacitor C32 and bringing them closer to the output capacitor C32, the resistance of the wiring portion that becomes the path through which a large current flows can be reduced. Therefore, the conduction loss can be reduced.

Next, the operation of the first conversion unit 1 will be described with reference to FIGS. 7 to 12.

In the first conversion unit 1, the switching circuit 11 may operate in full bridge operation or in half bridge operation. The full bridge operation and the half bridge operation are appropriately switched by the drive signals G11 to G14 input from the control unit 4.

First, a case where the switching circuit 11 operates in full bridge operation will be described with reference to FIGS. 7 to 9. FIG. 7 is a waveform diagram of each drive signal G11 to G16 when the switching circuit 11 is fully bridged. FIG. 7A shows the drive signal G11. FIG. 7B shows the drive signal G12. FIG. 7C shows the drive signal G13. FIG. 7D shows the drive signal G14. FIG. 7E shows the drive signal G15. FIG. 7 (f) shows the drive signal G16.

When the switching circuit 11 is fully bridged, the control unit 4 generates drive signals G11 to G14 shown in FIGS. 7 (a) to 7 (d), and generates each of the generated drive signals G11 to G14. Input to switching elements Q11 to Q14. Each of the drive signals G11 to G14 is a rectangular pulse wave having a predetermined frequency and has a duty ratio of about 50%. The drive signals G11 and G14 and the drive signals G12 and G13 are signals that are inverted from each other. When the drive signals G11 and G14 are on signals, the drive signals G12 and G13 are off signals, and conversely, when the drive signals G11 and G14 are off signals, the drive signals G12 and G13 are on signals.

The control unit 4 inputs the drive signals G11 to G14 shown in FIGS. 7 (a) to 7 (d) to the switching elements Q11 to Q14, so that the switching elements Q11 and Q14 are turned on and the switching elements Q14 are turned on. The period in which the switching elements Q12 and Q13 are off (period P1) and the period in which the switching elements Q11 and Q14 are off and the switching elements Q12 and Q13 are on (period P2) are alternately switched. A dead time period may be provided between the period P1 and the period P2 in order to prevent the generation of a through current. The dead time period is a period in which the plurality of switching elements Q11 to Q14 are all turned off (the plurality of drive signals G11 to G14 are all turned off).

8 and 9 show the current path when the switching circuit 11 is fully bridged. FIG. 8 shows the current path during the period P1, and FIG. 9 shows the current path during the period P2.

In the period P1, that is, during the period when the switching elements Q11 and Q14 are on and the switching elements Q12 and Q13 are off, as shown in FIG. 8, the input terminal T11a is on the primary side of the isolation transformer TR1. → Switching element Q11 → Resonant capacitor Cr1 → Primary winding W11 → Resonant reactor Lr1 → Switching element Q14 → Current flows in the path of input terminal T11b. Due to this current, an induced electromotive force is generated in each secondary winding W12b on the secondary side of the isolation transformer TR1, and as shown in FIG. 8, an output capacitor is generated from each secondary winding W12b via the switching element Q16. A current flows through C12 and the output capacitor C12 is charged. The voltage across the output capacitor C12 is the first output voltage V12 and is supplied to the load LO. In the period P1, the control unit 4 inputs the off signal drive signal G15 to the switching element Q15 and inputs the on signal drive signal G16 so that the switching element Q15 is turned off and the switching element Q16 is turned on. Input to the switching element Q16 (see FIGS. 7 (e) and 7 (f)).

On the other hand, in the period P2, that is, during the period when the switching elements Q11 and Q14 are off and the switching elements Q12 and Q13 are on, as shown in FIG. 9, the input is on the primary side of the isolation transformer TR1. A current flows in the path of terminal T11a → switching element Q13 → resonance reactor Lr1 → primary winding W11 → resonance capacitor Cr1 → switching element Q12 → input terminal T11b. Due to this current, an induced electromotive force is generated in each secondary winding W12a on the secondary side of the isolation transformer TR1, and as shown in FIG. 9, an output capacitor is generated from each secondary winding W12a via the switching element Q15. A current flows through C12 and the output capacitor C12 is charged. As described above, the voltage across the output capacitor C12 is the first output voltage V12 and is supplied to the load LO. In the period P2, the control unit 4 inputs the on signal drive signal G15 to the switching element Q15 and inputs the off signal drive signal G16 so that the switching element Q15 is turned on and the switching element Q16 is turned off. Input to the switching element Q16 (see FIGS. 7 (e) and 7 (f)).

The switching circuit 11 converts the input DC voltage into an AC voltage by performing the full bridge operation as described above. At this time, the voltage level of the voltage output from the switching circuit 11 is substantially the same as the voltage level of the voltage input to the switching circuit 11. Therefore, when the switching circuit 11 is fully bridged, the first output voltage V12 is V12 = (n12 / n11) × V11 using the transformation ratio (n11: n12) of the isolation transformer TR1 and the first input voltage V11. It becomes. That is, the ratio of the first input voltage V11 to the first output voltage V12 is n11: n12. The ratio of the first input voltage V11 to the first output voltage V12 is referred to as "transformation ratio of the first conversion unit 1."

Next, a case where the switching circuit 11 operates in a half-bridge operation will be described with reference to FIGS. 10 to 12. FIG. 10 is a waveform diagram of each drive signal G11 to G16 when the switching circuit 11 operates in a half-bridge operation. FIG. 10A shows the drive signal G11. FIG. 10B shows the drive signal G12. FIG. 10C shows the drive signal G13. FIG. 10D shows the drive signal G14. FIG. 10E shows the drive signal G15. FIG. 10F shows the drive signal G16.

When the switching circuit 11 is half-bridged, the control unit 4 generates drive signals G11 to G14 shown in FIGS. 10 (a) to 10 (d), and each of the generated drive signals G11 to G14 is used as each switching element. Input in Q11 to Q14. Each of the drive signals G11 and G12 is a rectangular pulse wave having a predetermined frequency and has a duty ratio of about 50%. The drive signal G11 and the drive signal G12 are signals that are inverted from each other. When the drive signal G11 is an on signal, the drive signal G12 becomes an off signal, and conversely, when the drive signal G11 is an off signal, the drive signal G12 becomes an on signal. Further, the drive signal G13 is a constant off signal, and the drive signal G14 is a constant on signal. The drive signal G13 may be always on and the drive signal G14 may be always off.

The control unit 4 inputs the drive signals G11 to G14 shown in FIGS. 10A to 10D to the switching elements Q11 to Q14, so that the switching element Q13 is always off and switching. During the period (period P3) when the switching element Q11 is on and the switching element Q12 is off while the element Q14 is always kept on, the switching element Q11 is off and the switching element Q12 is turned off. Alternately switches between the period in which is on (period P4). A dead time period may be provided between the period P3 and the period P4 in order to prevent the generation of a through current. The dead time period is a period in which the plurality of switching elements Q11 and Q12 are all turned off (the plurality of drive signals G11 and G12 are all turned off).

11 and 12 show a current path when the switching circuit 11 operates in a half-bridge operation. FIG. 11 shows the current path during the period P3, and FIG. 12 shows the current path during the period P4.

In the period P3, that is, during the period when the switching elements Q11 and Q14 are on and the switching elements Q12 and Q13 are off, as shown in FIG. 11, the input terminal T11a → switching on the primary side of the isolation transformer TR1. A current flows in the path of element Q11 → resonance capacitor Cr1 → primary winding W11 → resonance reactor Lr1 → switching element Q14 → input terminal T11b. Due to this current, an induced electromotive force is generated in each secondary winding W12b on the secondary side of the isolated transformer TR1 as shown in FIG. 11, and an output capacitor is generated from each secondary winding W12b via the switching element Q16. A current flows through C12 and the output capacitor C12 is charged. That is, the current path is the same as the period P1 during the full bridge operation. The voltage across the output capacitor C12 is the first output voltage V12 and is supplied to the load LO. In the period P3, the control unit 4 inputs the off signal drive signal G15 to the switching element Q15 and inputs the on signal drive signal G16 so that the switching element Q15 is turned off and the switching element Q16 is turned on. Input to the switching element Q16 (see FIGS. 10 (e) and 10 (f)).

On the other hand, in the period P4, that is, during the period when the switching elements Q12 and Q14 are on and the switching elements Q11 and Q13 are off, the power stored in the resonance capacitor Cr1 is released, and FIG. As shown, on the primary side of the insulating transformer TR1, current flows in the path of the resonance capacitor Cr1 → the switching element Q12 → the switching element Q14 → the resonance reactor Lr1 → the primary winding W11 → the resonance capacitor Cr1. Due to this current, an induced electromotive force is generated in each secondary winding W12a on the secondary side of the isolation transformer TR1, and as shown in FIG. 12, an output capacitor is generated from each secondary winding W12a via the switching element Q15. A current flows through C12 and the output capacitor C12 is charged. As described above, the voltage across the output capacitor C12 is the first output voltage V12 and is supplied to the load LO. In the period P4, the control unit 4 inputs the on signal drive signal G15 to the switching element Q15 and inputs the off signal drive signal G16 so that the switching element Q15 is turned on and the switching element Q16 is turned off. Input to the switching element Q16 (see FIGS. 10 (e) and 10 (f)).

The switching circuit 11 converts the input DC voltage into an AC voltage by performing the half-bridge operation as described above. At this time, the voltage level of the voltage output from the switching circuit 11 is approximately half (1/2 times) the voltage level of the voltage input to the switching circuit 11. Therefore, when the switching circuit 11 operates in a half-bridge operation, the first output voltage V12 is V12 = (n12 / n11) × (using the transformation ratio (n11: n12) of the isolation transformer TR1 and the first input voltage V11. It becomes V11 / 2). That is, the ratio of the first input voltage V11 to the first output voltage V12 (transformation ratio of the first conversion unit 1) is 2 × n11: n12.

As described above, in the switching circuit 11, the control unit 4 switches between the full bridge operation and the half bridge operation. At this time, as described above, the transformation ratio of the first conversion unit 1 changes depending on whether the switching circuit 11 operates in full bridge operation or the switching circuit 11 operates in half bridge operation. When the switching circuit 11 operates in full bridge, the first conversion unit 1 enters the first transformer state in which transformation is performed at the first transformation ratio, and when the switching circuit 11 operates in half bridge, the first conversion unit 1 becomes the second. It is in the second transformation state where transformation is performed at the transformation ratio. Therefore, in the power supply device A1, the second transformation ratio is larger than the first transformation ratio.

The second conversion unit 2 operates on the same operating principle as the first conversion unit 1. Therefore, a detailed description of the operation of the second conversion unit 2 will be omitted.

In the second conversion unit 2, the switching circuit 21 switches between the full bridge operation and the half bridge operation by the control unit 4, similarly to the first conversion unit 1. At this time, the transformation ratio of the second conversion unit 2 changes depending on whether the switching circuit 21 operates in full bridge operation or the switching circuit 21 operates in half bridge operation. When the switching circuit 21 operates in full bridge, the second conversion unit 2 enters the third transformer state in which transformation is performed at the third transformation ratio, and when the switching circuit 21 operates in half bridge, the second conversion unit 2 moves to the fourth. It becomes the fourth transformation state where transformation is performed at the transformation ratio. Therefore, in the power supply device A1, the fourth transformation ratio is larger than the third transformation ratio.

Next, the operation of the auxiliary conversion unit 3 will be described with reference to FIGS. 13 and 14. In the auxiliary conversion unit 3, the switching circuit 31 has a period (first period) in which the switching element Q31 is on and the switching element Q32 is off by the drive signals G31 and G32 input from the control unit 4. , The period in which the switching element Q31 is off and the switching element Q32 is on (second period) is alternately switched. A dead time period may be provided between the first period and the second period in order to prevent the generation of a through current. The dead time period is a period in which the two switching elements Q31 and Q32 are all turned off (the plurality of drive signals G31 and G32 are all turned off).

FIG. 13 shows the current path during the first period, and FIG. 14 shows the current path during the second period.

In the first period, that is, in the period when the switching element Q31 is on and the switching element Q32 is off, as shown in FIG. 13, the input terminal T31a → the switching element Q31 → the reactor Lr31 → the output capacitor C32. → Current flows through the path of the input terminal T31b. At this time, a current flows through the output capacitor C32, and the output capacitor C32 is charged. The voltage across the output capacitor C32 is the auxiliary output voltage V32, which is supplied to the load LO.

On the other hand, in the second period, that is, during the period when the switching element Q31 is off and the switching element Q32 is on, the power stored in the reactor Lr31 is released, and as shown in FIG. Current flows in the path of reactor Lr31 → output capacitor C32 → switching element Q32 → reactor Lr31. At this time, a current flows through the output capacitor C32, and the output capacitor C32 is charged. The voltage across the output capacitor C32 is the auxiliary output voltage V32, which is supplied to the load LO.

By operating as described above, the auxiliary conversion unit 3 transforms (steps down) the input DC voltage (auxiliary input voltage V31) and outputs it (generates the auxiliary output voltage V32). At this time, in the second period, there is no power supply from the DC power supply P, and the power stored in the reactor Lr31 is released. Therefore, if the second period is longer than the first period, the auxiliary conversion unit 3 The transformation ratio (step-down ratio) increases. Therefore, by setting the duty ratios of the drive signals G31 and G32 so that the first period is longer than the second period, the transformation ratio of the auxiliary conversion unit 3 becomes smaller, and the first period becomes larger than the second period. By setting the duty ratio of each drive signal G31 and G32 so as to be short, the transformation ratio of the auxiliary conversion unit 3 becomes large.

Next, an operation example of the power supply device A1 will be described. The power supply voltage Vin supplied from the DC power supply P to the power supply device A1 is assumed to fluctuate in the range of, for example, 36 to 60V. The power supply device A1 selectively switches between when each switching circuit 11 and 21 operates in full bridge operation and when each switching circuit 11 and 21 operates in half bridge according to the supplied power supply voltage Vin. In the following examples, the power supply device A1 shall convert the supplied power supply voltage Vin into an output voltage Vout of 1V (target level). Further, it is assumed that the winding number ratio of the isolation transformer TR1 of the first conversion unit 1 is 9: 1. Therefore, when the switching circuit 11 is fully bridged, the transformation ratio (V11: V12) of the first conversion unit 1 is 9: 1, and when the switching circuit 11 is half-bridged, the transformation ratio of the first conversion unit 1 is. (V11: V12) is 18: 1. On the other hand, it is assumed that the winding number ratio of the isolation transformer TR2 of the second conversion unit 2 is 16: 1. Therefore, when the switching circuit 21 operates in full bridge, the transformation ratio (V21: V22) of the second conversion unit 2 becomes 16: 1, and when the switching circuit 21 operates in half bridge, the transformation ratio of the second conversion unit 2 becomes. (V21: V22) is 32: 1.

First, the operation of the power supply device A1 when the voltage level of the power supply voltage Vin is 48V will be described. That is, the operation of the power supply device A1 when the power supply voltage Vin of 48V is stepped down to the output voltage Vout of 1V will be described. In this case, the control unit 4 causes the switching circuit 11 of the first conversion unit 1 to perform a full bridge operation, so that the first conversion unit 1 steps down the 9V first input voltage V11 to the 1V first output voltage V12. Further, the control unit 4 causes the switching circuit 21 of the second conversion unit 2 to perform a half-bridge operation, so that the second conversion unit 2 steps down the 32V second input voltage V21 to the 1V second output voltage V22. Then, the control unit 4 steps down the 7V auxiliary input voltage V31 to the 1V auxiliary output voltage V32 by the auxiliary conversion unit 3. The power supply device A1 operates as described above to divide the 48V power supply voltage Vin into the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3, respectively, and convert it to the output voltage Vout of 1V (step-down). ).

Next, the operation of the power supply device A1 when the voltage level of the power supply voltage Vin is 36V will be described. That is, the operation of the power supply device A1 when the power supply voltage Vin of 36 V is stepped down to the output voltage Vout of 1 V will be described. In this case, the control unit 4 causes the switching circuit 11 of the first conversion unit 1 to perform a half-bridge operation, so that the first conversion unit 1 steps down the first input voltage V11 of 18V to the first output voltage V12 of 1V. Further, the control unit 4 causes the switching circuit 21 of the second conversion unit 2 to perform a full bridge operation, so that the second conversion unit 2 steps down the 16V second input voltage V21 to the 1V second output voltage V22. Then, the control unit 4 steps down the 2V auxiliary input voltage V31 to the 1V auxiliary output voltage V32 by the auxiliary conversion unit 3. The power supply device A1 operates as described above to divide the 36V power supply voltage Vin into the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3, respectively, and convert it to the output voltage Vout of 1V (step-down). ).

Next, the operation of the power supply device A1 when the voltage level of the power supply voltage Vin is 60V will be described. That is, the operation of the power supply device A1 when the power supply voltage Vin of 60 V is stepped down to the output voltage Vout of 1 V will be described. In this case, the control unit 4 causes the switching circuit 11 of the first conversion unit 1 to perform a half-bridge operation, so that the first conversion unit 1 steps down the first input voltage V11 of 18V to the first output voltage V12 of 1V. Further, the control unit 4 causes the switching circuit 21 of the second conversion unit 2 to perform a half-bridge operation, so that the second conversion unit 2 steps down the 32V second input voltage V21 to the 1V second output voltage V22. Then, the control unit 4 steps down the 10V auxiliary input voltage V31 to the 1V auxiliary output voltage V32 by the auxiliary conversion unit 3. The power supply device A1 operates as described above, divides the power supply voltage Vin of 60 V into the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3, respectively, and converts it into the output voltage Vout of 1 V (lowering). ).

As described above, the power supply device A1 switches between the case where each of the switching circuits 11 and 21 operates in full bridge operation and the case where each switching circuit operates in half bridge according to the voltage level of the supplied power supply voltage Vin. In the operation example of the power supply device A1 described above, the case where the target level of the output voltage Vout is 1V is shown, but the target level is not limited to 1V. For example, it may be 3.3V, 5V, 12V, 24V or the like. For example, various target levels can be met by appropriately changing the transformation ratios of the isolation transformers TR1 and TR2.

The actions and effects of the power supply device A1 configured as described above are as follows.

According to the power supply device A1, the first conversion unit 1 and the auxiliary conversion unit 3 are provided. The first conversion unit 1 converts the first input voltage V11 into the first output voltage V12, and switches between a first transformation state in which transformation is performed at the first transformation ratio and a second transformation state in which transformation is performed at the second transformation ratio. .. The auxiliary conversion unit 3 converts the auxiliary input voltage V31 into the auxiliary output voltage V32, and the transformation ratio changes in conjunction with the change in the voltage level of the auxiliary input voltage V31. According to this configuration, the transformation ratios of the first conversion unit 1 and the auxiliary conversion unit 3 can be appropriately changed according to the fluctuation of the power supply voltage Vin. Therefore, the power supply device A1 can stabilize the output voltage even when the supplied power supply voltage Vin fluctuates.

According to the power supply device A1, the first conversion unit 1 and the auxiliary conversion unit 3 are connected between the pair of input terminals Tin and the pair of output terminals Tout, respectively. Further, the first conversion unit 1 and the auxiliary conversion unit 3 are connected to a pair of input terminals Tin to which the power supply voltage Vin is applied by connecting each input side in series. Therefore, the power supply voltage Vin is divided to generate the first input voltage V11 and the auxiliary input voltage V31. According to this configuration, the first conversion unit 1 and the auxiliary conversion unit 3 can share the step-down of the power supply voltage Vin to the output voltage Vout.

According to the power supply device A1, the first conversion unit 1 switches between the first transformation state and the second transformation state, and the second conversion unit 2 switches between the third transformation state and the fourth transformation state. Unlike the power supply device A1, the first conversion unit 1 cannot switch between the first transformation state and the second transformation state, and the second conversion unit 2 cannot switch between the third transformation state and the fourth transformation state. In this case, as the power supply voltage Vin increases, the power ratio transformed by the auxiliary conversion unit 3 (power ratio of the auxiliary conversion unit 3) increases. On the other hand, in the power supply device A1, when the power supply voltage Vin increases, the first conversion unit 1 is subjected to a transformation state in which the transformation ratio is relatively large between the first transformation state and the second transformation state (the first in the present embodiment). It is possible to switch to (2 transformer states), and the second conversion unit 2 is placed in a transformer state in which the transformation ratio is relatively large between the third transformer state and the fourth transformer state (the fourth transformer state in this embodiment). Can be switched to. As a result, the power ratios of the first conversion unit 1 and the second conversion unit 2 increase, and the increase in the power ratio of the auxiliary conversion unit 3 is suppressed. In the power supply device A1, the switching operations of the switching elements Q11 to Q14 (first conversion unit 1) of the switching circuit 11 and the switching elements Q21 to Q24 (second conversion unit 2) of the switching circuit 21 are controlled by soft switching. The switching operation of each of the switching elements Q31 and Q32 (auxiliary conversion unit 3) of the switching circuit 31 is controlled by hard switching. When controlled by hard switching, the switching loss is larger than when controlled by soft switching. Therefore, even if the power supply voltage Vin increases, the power supply device A1 switches between the first transformation state and the second transformation state of the first conversion unit 1, and the third transformation state and the fourth transformation state of the second conversion unit 2. By switching to the transformer state, it is possible to suppress an increase in the power ratio of the auxiliary conversion unit 3 that operates by hard switching, so that an increase in power loss due to the auxiliary conversion unit 3 can be suppressed. That is, the power supply device A1 can reduce the power loss.

According to the power supply device A1, a second conversion unit 2 configured in the same manner as the first conversion unit 1 is provided. The second conversion unit 2 switches between a third transformation state in which transformation is performed at the third transformation ratio and a fourth transformation state in which transformation is performed at the fourth transformation ratio. According to this configuration, the auxiliary conversion unit is further changed by switching between the first transformation state and the second transformation state by the first conversion unit 1 and switching between the third transformation state and the fourth transformation state by the second conversion unit 2. The power ratio of 3 can be reduced. Therefore, the power supply device A1 can further reduce the power loss as compared with the case where either the first conversion unit 1 or the second conversion unit 2 and the auxiliary conversion unit 3 are provided.

According to the power supply device A1, the first conversion unit 1 includes a switching circuit 11, and the switching circuit 11 operates as a full-bridge inverter (full-bridge operation) and a half-bridge inverter (half-bridge operation). Operation) and switch. As described above, when the switching circuit 11 is fully bridged, the output voltage of the switching circuit 11 is substantially the same as the input voltage of the switching circuit 11. On the other hand, when the switching circuit 11 operates in half-bridge operation, the output voltage of the switching circuit 11 becomes approximately 1/2 times the input voltage of the switching circuit 11. Therefore, the first conversion unit 1 can switch between the first transformation state and the second transformation state by switching between the full bridge operation and the half bridge operation of the switching circuit 11. Similarly, in the second conversion unit 2, the third transformation state and the fourth transformation state can be switched by switching between the full bridge operation and the half bridge operation of the switching circuit 21.

According to the power supply device A1, the isolation transformer TR1 includes two secondary windings W12 connected in parallel. In the power supply device A1, the isolation transformer TR1 steps down the voltage applied to the primary winding W11 and transmits it to each secondary winding W12. At this time, the current flowing through each secondary winding W12 is larger than the current flowing through the primary winding W11. In particular, the larger the step-down ratio of the isolation transformer TR1, the larger the current difference, and the larger the current flowing through each secondary winding W12. Therefore, by connecting the two secondary windings W12 in parallel, the current flowing through each secondary winding W12 can be reduced. Therefore, the power supply device A1 can reduce the power loss (overcurrent loss) in each secondary winding W12. In particular, by setting each of the secondary windings W12a and W12b to one turn (the number of turns n12 is 1), the current flowing through each of the secondary windings W12 can be further reduced. The same applies to the isolation transformer TR2.

Next, each modification of the power supply device A1 according to the first embodiment will be described.

In the power supply device A1, the first conversion unit 1 and the second conversion unit 2 may be interleaved driven. Specifically, a predetermined phase difference (for example, 90 °) is generated between the first output voltage V12 output from the first conversion unit 1 and the second output voltage V22 output from the second conversion unit 2. It may be controlled to. For example, the above-mentioned phase difference can be provided by shifting each phase of each drive signal G21 to G24 by a predetermined value (for example, 90 °) with respect to each phase of each drive signal G11 to G14. As a result, the ripple component contained in the first output voltage V12 and the ripple component contained in the second output voltage V22 cancel each other out, so that the ripple component contained in the output voltage Vout can be reduced.

As shown in FIG. 15, the power supply device A1 may further include a voltage sensor S1 for detecting the power supply voltage Vin, and may be configured so that the detection value of the voltage sensor S1 is input to the control unit 4. As a result, the control unit 4 switches between the full bridge operation and the half bridge operation of the first conversion unit 1 and the full bridge operation of the second conversion unit 2 based on the power supply voltage Vin input from the voltage sensor S1. At least one of switching between and half-bridge operation can be controlled.

As shown in FIG. 16, the power supply device A1 may further include a voltage sensor S2 for detecting the auxiliary input voltage V31 so that the detection value of the voltage sensor S2 is input to the control unit 4. As a result, the control unit 4 switches between the full bridge operation and the half bridge operation of the first conversion unit 1 and the second conversion unit 2 based on the detection value of the auxiliary input voltage V31 input from the voltage sensor S2. At least one of switching between full-bridge operation and half-bridge operation can be controlled.

In the power supply device A1, the switching circuit 21 of the second conversion unit 2 may be configured by a half bridge using two switching elements Q21 and Q22. That is, the switching elements Q21 and Q22 may be half-bridged. In this case, a capacitor is connected instead of the switching elements Q23 and Q24, respectively. Alternatively, it may be configured by a half bridge using two switching elements Q23 and Q24. In this case, a capacitor is connected instead of the switching elements Q21 and Q22, respectively. As a result, the number of switching elements in the switching circuit 21 (second conversion unit 2) can be reduced, so that the control unit 4 can be easily controlled. However, in the modified example, since the switching circuit 21 cannot switch between the full bridge operation and the half bridge operation, the switching between the full bridge operation and the half bridge operation of the switching circuit 11 corresponds to the fluctuation of the power supply voltage Vin. I need to let you. At this time, it may be difficult to adjust the timing for switching between the full bridge operation and the half bridge operation of the first conversion unit 1 (switching circuit 11). Therefore, it is preferable to switch between the full bridge operation and the half bridge operation at the power supply voltage Vin which is rarely used. The infrequently used power supply voltage Vin is a voltage level that is unlikely to be set in the DC power supply P that can be connected to the power supply device A1.

In the power supply device A1, the switching operation of each of the switching elements Q31 and Q32 (auxiliary conversion unit 3) may be controlled by soft switching instead of hard switching. The soft switching may be ZVS or ZCS. As a result, the power loss due to the auxiliary conversion unit 3 can be further reduced.

In the power supply device A1, at least one of the first conversion unit 1 and the second conversion unit 2 may be composed of a non-isolated DC / DC converter instead of an insulated DC / DC converter. For example, by using a tap inductor instead of the isolation transformer TR1, the first conversion unit 1 can be configured as a non-isolated DC / DC converter. Similarly, by using a tap inductor instead of the isolation transformer TR2, the second conversion unit 2 can be configured as a non-isolated DC / DC converter. A non-isolated DC / DC converter using such a tap inductor is called a tap inductor converter.

In the power supply device A1, one or more conversion units, each of which is configured in the same manner as the first conversion unit 1 or the second conversion unit 2, may be added. As a result, the auxiliary input voltage V31 of the auxiliary conversion unit 3 can be reduced, and the ratio of electric power transformed by the auxiliary conversion unit 3 can be reduced. Therefore, the power supply device A1 can further reduce the power loss due to the auxiliary conversion unit 3. Further, in the power supply device A1, one or more auxiliary conversion units, each of which is configured in the same manner as the auxiliary conversion unit 3, may be added.

In the power supply device A1, at least one of the first conversion unit 1 and the second conversion unit 2 may not be operated. For example, by always turning off the drive signals G11 to G14 input to the first conversion unit 1, the first conversion unit 1 can be prevented from operating. Similarly, by always turning off the drive signals G21 to G24 input to the second conversion unit 2, the second conversion unit 2 can be prevented from operating.

In the power supply device A1, the control unit 4 positions the drive signal (leading drive signal) input to the leading arm of the switching circuit 11 and the driving signal (following drive signal) input to the trailing arm of the switching circuit 11. The phase difference may be adjusted. In the first conversion unit 1, when the switching circuit 11 is in full bridge operation, the switching elements Q11 and Q14 are the leading arms, and the switching elements Q12 and Q13 are the trailing arms. On the other hand, when the switching circuit 11 is in half-bridge operation, the switching element Q11 is the leading arm and the switching element Q12 is the trailing arm. In the present disclosure, the terms "preceding" and "following" are used merely as labels and are not necessarily intended to permutate those objects. As a result, the first output voltage V12 can be finely adjusted, so that it is possible to cope with slight fluctuations in the power supply voltage Vin. The same applies to the second conversion unit 2. The switching elements Q11 and Q14 correspond to the "first leading arm" described in the claims, respectively, and the switching elements Q12 and Q13 correspond to the "first trailing arm" described in the claims, respectively. .. The switching elements Q21 and Q24 each correspond to the "second leading arm" described in the claims, and the switching elements Q22 and Q23 correspond to the "second trailing arm" described in the claims, respectively. .. Further, the drive signals G11 and G14 correspond to the "preceding first drive signal" described in the claims, respectively, and the drive signals G12 and G13 correspond to the "following first drive signal" described in the claims, respectively. Corresponds to. The drive signals G21 and G24 correspond to the "preceding second drive signal" described in the claims, respectively, and the drive signals G22 and G23 correspond to the "following second drive signal" described in the claims, respectively. Equivalent to.

In the power supply device A1, the control unit 4 may adjust the frequency of the AC voltage output from the switching circuit 11 by adjusting the frequencies of the preceding drive signal and the following driving signal described above. As a result, the first output voltage V12 can be finely adjusted, so that it is possible to cope with slight fluctuations in the power supply voltage Vin. The same applies to the second conversion unit 2.

In the power supply device A1, the capacitance value of the input capacitor C31 of the auxiliary conversion unit 3 may be larger than the capacitance values of the input capacitor C11 of the first conversion unit 1 and the input capacitor C21 of the second conversion unit 2. As a result, the voltage fluctuation of the auxiliary conversion unit 3 can be suppressed, and the ripple component contained in the output voltage Vout can be reduced. Further, since the voltage surge generated when the power supply device A1 is started can be suppressed, the withstand voltage of each switching element Q31 and Q32 can be reduced, and the component cost can be reduced. Alternatively, it is possible to improve other performances (for example, responsiveness of switching operation) of the switching elements Q31 and Q32 while suppressing an increase in component cost.

In the power supply device A1, a Zener diode may be connected in parallel to the input capacitor C31 of the auxiliary conversion unit 3. As a result, the voltage surge generated when the power supply device A1 is started can be suppressed. Therefore, the withstand voltage of each switching element Q31 and Q32 can be reduced, and the component cost can be reduced. Alternatively, it is possible to improve other performances (for example, responsiveness of switching operation) of the switching elements Q31 and Q32 while suppressing an increase in component cost.

In the power supply device A1, when the power supply device A1 is started, the auxiliary conversion unit 3 is operated before the first conversion unit 1 and the second conversion unit 2, and when the power supply device A1 is stopped, the auxiliary conversion unit 3 is first operated. It may be stopped after the conversion unit 1 and the second conversion unit 2. As a result, the voltage surge that occurs when the power supply device A1 is started can be suppressed without providing the Zener diode described above.

In the power supply device A1, the configuration of the isolation transformer TR1 may be the configuration shown in FIG. In the isolation transformer TR1 shown in FIG. 17, a plurality of primary windings W11 are connected in series, and a plurality of secondary windings W12 are connected in parallel. Further, by setting the number of turns n12 to 1 and connecting a plurality of the secondary windings W12a and W12b in parallel, the current can be dispersed and the power loss can be reduced. The number of secondary windings W12 is not limited to the number shown in FIG. 17, and the larger the number, the more the current flowing through each secondary winding W12 (W12a, W12b) can be reduced. However, since the power supply device A1 becomes larger as the number of secondary windings W12 increases, it is preferable to set the number of secondary windings W12 according to the specifications of the power supply device A1.

In the power supply device A1, switching between the first transformer state and the second transformer state of the first conversion unit 1 is not switching between full bridge operation and half bridge operation, but one or more connections to each secondary winding W12. It may be switched by the isolation transformer TR1 to which the point is connected. The isolation transformer TR1 to which one or more connection points are connected can change the transformation ratio by switching the connection points. Therefore, by switching the connection point, the control unit 4 can switch between the first transformer state that transforms at the first transformer ratio and the second transformer state that transforms at the second transformer ratio. The second conversion unit 2 may also be switched by an isolation transformer TR2 in which one or more connection points are connected to each secondary winding W22. That is, the control unit 4 may switch between the third transformer state and the fourth transformer state of the second conversion unit 2 by switching one or more connection points of the isolation transformer TR2.

In the power supply device A1, the auxiliary conversion unit 3 may be composed of an insulated DC / DC converter instead of a non-isolated DC / DC converter. As a result, the input side and each output side of the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3 are all insulated, so that the input side and the output side of the power supply device A1 are insulated. Therefore, the power supply device A1 can be connected to the DC power supply P whose power supply voltage Vin is larger than a predetermined level (for example, 60V) (for example, 400V). Therefore, the power supply device A1 has a wider permissible range of the power supply voltage Vin, and is more versatile.

In the power supply device A1, the auxiliary conversion unit 3 may be composed of a step-up converter instead of the step-down converter. FIG. 18 shows an example of the circuit configuration of the auxiliary conversion unit 3 configured as a step-up converter. The auxiliary conversion unit 3 shown in FIG. 18 is different from the auxiliary conversion unit 3 shown in FIG. 3 in that the reactor Lr31 and the switching element Q31 are interchanged. Alternatively, the auxiliary conversion unit 3 may be composed of a buck-boost converter. FIG. 19 shows an example of the circuit configuration of the auxiliary conversion unit 3 configured as a buck-boost converter. In the auxiliary conversion unit 3 shown in FIG. 19, the switching element Q31 and the switching element Q32 are connected in series between the pair of input terminals T31a and T31b, and the switching element Q33 and the switching element Q34 are connected to the pair of output terminals T32a and T32b. Are connected in series between. One end of the reactor Lr31 is connected to the connection point between the switching element Q31 and the switching element Q32, and the other end is connected to the connection point between the switching element Q33 and the switching element Q34. In the auxiliary conversion unit 3 shown in FIG. 19, the switching elements Q31 and Q34 are on and the switching elements Q32 and Q33 are off, and the switching elements Q31 and Q34 are off and the switching element is off. The period in which Q32 and Q33 are on alternates with each other.

In the power supply device A1, the number of switching elements Q32 of the switching circuit 31 (auxiliary conversion unit 3) may be not one but a plurality. FIG. 20 shows an example of the circuit configuration of the auxiliary conversion unit 3 according to this modification. FIG. 20 shows a configuration in which a plurality of switching elements Q32 are connected in the switching circuit 31 (step-down converter) shown in FIG. The plurality of switching elements Q32 are connected in parallel with each other. The drain terminal of each switching element Q32 is connected to the source terminal of the switching element Q31, and the source terminal of each switching element Q32 is connected to the input terminal T31b. In the circuit configuration shown in FIG. 20, a diode D31 (for example, a Schottky barrier diode) is connected in antiparallel to a plurality of switching elements Q32, but the diode D31 may not be present. When the switching circuit 31 includes a plurality of switching elements Q32, the plurality of switching elements Q32 may be arranged on the circuit board CB1 as shown in FIG. 21, for example. FIG. 21 is a component layout diagram showing a power supply device including the auxiliary conversion unit 3 having the circuit configuration shown in FIG. 20, and shows the first surface side of the circuit board CB1. As shown in FIG. 21, the plurality of switching elements Q32 are arranged in a matrix, and are arranged between the input capacitor C31 and the isolation transformer TR1 in the longitudinal direction of the circuit board CB1. As described above, by connecting a plurality of switching elements Q32 in parallel, the amount of current flowing through each switching element Q32 can be reduced, so that the conduction loss in the switching circuit 31 (auxiliary conversion unit 3) can be reduced.

FIG. 22 shows the power supply device A2 according to the second embodiment. Unlike the power supply device A1, the power supply device A2 has a voltage level of the output voltage Vout higher than the voltage level of the power supply voltage Vin. The power supply device A2 is a step-up voltage conversion device. FIG. 22 is a schematic view showing the overall configuration of the power supply device A2.

In the power supply device A2, each input side of the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3 is connected in parallel to the pair of input terminals Tin. The first input voltage V11, the second input voltage V21, and the auxiliary input voltage V31 are the same as the power supply voltage Vin, respectively. That is, Vin = V11 = V21 = V31.

In the power supply device A2, the input sides of the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3 are connected in series to the pair of output terminals Tout. The first output voltage V12, the second output voltage V22, and the auxiliary output voltage V32 are combined and applied as the output voltage Vout to the pair of output terminals Tout. That is, Vout = V12 + V22 + V32.

The first conversion unit 1 boosts the first input voltage V11 to the first output voltage V12. Therefore, the voltage level of the first output voltage V12 is larger than the voltage level of the first input voltage V11. In the power supply device A2, in the isolation transformer TR1, the number of turns n11 of the primary winding W11 is smaller than the number of turns n12 of the secondary windings W12a and W12b, respectively. Therefore, the isolation transformer TR1 boosts the voltage input to the primary side and outputs it from the secondary side.

The second conversion unit 2 boosts the second input voltage V21 to the second output voltage V22. Therefore, the voltage level of the second output voltage V22 is larger than the voltage level of the second input voltage V21. In the power supply device A2, in the isolation transformer TR2, the number of turns n21 of the primary winding W21 is smaller than the number of turns n22 of the secondary windings W22a and W22b, respectively. Therefore, the isolation transformer TR2 boosts the voltage input to the primary side and outputs it from the secondary side.

The auxiliary conversion unit 3 may be configured by the step-down converter shown in FIG. 4 or FIG. 20, may be configured by the step-up converter shown in FIG. 18, or may be configured by the buck-boost converter shown in FIG. It may have been. In the power supply device A2, the auxiliary conversion unit 3 is configured by the boost type shown in FIG. 18, and boosts the auxiliary input voltage V31 to the auxiliary output voltage V32.

Other configurations of the power supply device A2 are the same as those of the power supply device A1.

Next, an operation example of the power supply device A2 will be described. The power supply voltage Vin supplied from the DC power supply P to the power supply device A2 is assumed to fluctuate in the range of, for example, 12 to 24V. The power supply device A2 selectively switches between when each switching circuit 11 and 21 operates in full bridge operation and when each switching circuit 11 and 21 operates in half bridge operation according to the supplied power supply voltage Vin. In the following examples, the power supply device A2 shall convert the supplied power supply voltage Vin into an output voltage Vout of 400 V (target level). Further, it is assumed that the winding number ratio of the isolation transformer TR1 of the first conversion unit 1 is 1:10. Therefore, when the switching circuit 11 is fully bridged, the transformation ratio (V11: V12) of the first conversion unit 1 is 1:10, and when the switching circuit 11 is half-bridged, the transformation ratio of the first conversion unit 1 is 1. (V11: V12) is 1: 5. On the other hand, it is assumed that the winding number ratio of the isolation transformer TR2 of the second conversion unit 2 is 1:20. Therefore, when the switching circuit 21 operates in full bridge, the transformation ratio (V21: V22) of the second conversion unit 2 becomes 1:20, and when the switching circuit 21 operates in half bridge, the transformation ratio of the second conversion unit 2 becomes. (V21: V22) is 1:10.

First, the operation of the power supply device A2 when the voltage level of the power supply voltage Vin is 12V will be described. That is, the operation of the power supply device A2 when boosting the power supply voltage Vin of 12V to the output voltage Vout of 400V will be described. In this case, the control unit 4 causes the switching circuit 11 of the first conversion unit 1 to perform a full bridge operation, so that the first conversion unit 1 boosts the 12V first input voltage V11 to the 120V first output voltage V12. Further, the control unit 4 boosts the 12V second input voltage V21 to the 240V second output voltage V22 by the second conversion unit 2 by fully bridging the switching circuit 21 of the second conversion unit 2. Then, the control unit 4 boosts the auxiliary input voltage V31 of 12 V to the auxiliary output voltage V32 of 40 V by the auxiliary conversion unit 3. The power supply device A1 operates as described above to divide the 12V power supply voltage Vin into the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3, respectively, and convert (boost) the output voltage Vout to 400V. ).

Next, the operation of the power supply device A2 when the voltage level of the power supply voltage Vin is 18V will be described. That is, the operation of the power supply device A2 when boosting the power supply voltage Vin of 18V to the output voltage Vout of 400V will be described. In this case, the control unit 4 causes the switching circuit 11 of the first conversion unit 1 to perform a full bridge operation, so that the first conversion unit 1 boosts the 18V first input voltage V11 to the 180V first output voltage V12. Further, the control unit 4 causes the switching circuit 21 of the second conversion unit 2 to perform a half-bridge operation, so that the second conversion unit 2 boosts the 18V second input voltage V21 to the 180V second output voltage V22. Then, the control unit 4 boosts the auxiliary input voltage V31 of 12 V to the auxiliary output voltage V32 of 40 V by the auxiliary conversion unit 3. The power supply device A1 operates as described above to divide the 18V power supply voltage Vin into the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3, respectively, and convert (boost) the output voltage Vout to 400V. ).

Next, the operation of the power supply device A2 when the voltage level of the power supply voltage Vin is 24V will be described. That is, the operation of the power supply device A2 when boosting the power supply voltage Vin of 24 V to the output voltage Vout of 400 V will be described. In this case, the control unit 4 causes the switching circuit 11 of the first conversion unit 1 to perform a half-bridge operation, so that the first conversion unit 1 boosts the 24V first input voltage V11 to the 120V first output voltage V12. Further, the control unit 4 boosts the 24V second input voltage V21 to the 240V second output voltage V22 by the second conversion unit 2 by half-bridge operation of the switching circuit 21 of the second conversion unit 2. Then, the control unit 4 boosts the auxiliary input voltage V31 of 24 V to the auxiliary output voltage V32 of 40 V by the auxiliary conversion unit 3. The power supply device A1 operates as described above to divide the 24V power supply voltage Vin into the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3, respectively, and convert (boost) the output voltage Vout to 400V. ).

As described above, the power supply device A2 switches between the case where each switching circuit 11 and 21 operates in full bridge operation and the case where each switching circuit operates in half bridge according to the voltage level of the supplied power supply voltage Vin. In the operation example of the power supply device A2 described above, the case where the target level of the output voltage Vout is 400V is shown, but the target level is not limited to 400V. Further, in the power supply device A2 as well, each modification with respect to the power supply device A1 may be appropriately combined.

The actions and effects of the power supply device A2 configured as described above are as follows.

According to the power supply device A2, like the power supply device A1, the first conversion unit 1 and the auxiliary conversion unit 3 are provided. According to this configuration, the transformation ratios of the first conversion unit 1 and the auxiliary conversion unit 3 can be appropriately changed according to the fluctuation of the power supply voltage Vin. Therefore, the power supply device A2 can stabilize the output voltage even when the supplied power supply voltage Vin fluctuates.

According to the power supply device A2, the first conversion unit 1 and the auxiliary conversion unit 3 are connected between the pair of input terminals Tin and the pair of output terminals Tout, respectively. Further, each output side of the first conversion unit 1 and the auxiliary conversion unit 3 is connected in series and connected to a pair of output terminals Tout. Therefore, the first output voltage V12 and the auxiliary output voltage V32 are combined to generate the output voltage Vout. According to this configuration, in boosting the power supply voltage Vin to the output voltage Vout, the first conversion unit 1 and the auxiliary conversion unit 3 can share the step.

According to the power supply device A2, the same effect as that of the power supply device A1 can be obtained by the same or similar configuration as the power supply device A1.

In the first embodiment and the second embodiment, the case where each of the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3 includes the output capacitors C12, C22, and C32 is shown. Not limited to this. For example, a common output capacitor may be connected between the pair of output terminals Tout. The common output capacitor is arranged between each output side of the first conversion unit 1, the second conversion unit 2, and the auxiliary conversion unit 3 and the pair of output terminals Tout.

In the first embodiment and the second embodiment, the case where the power supply device A1 includes the control unit 4 is shown, but the present invention is not limited thereto. For example, the control unit 4 may be provided outside the power supply device A1 so that the drive signals G11 to G16, G21 to G26, G31, and G32 are input from the control unit 4 provided outside.

The power supply device according to the present disclosure is not limited to the above-described embodiment. The specific configuration of each part of the power supply device of the present disclosure can be freely redesigned.

The power supply device according to the present disclosure includes embodiments relating to the following appendices.
[Appendix 1]
A power supply device that converts the power supply voltage input from a DC power supply to a target level output voltage.
The input terminal to which the power supply voltage is applied and
The output terminal to which the output voltage is applied and
The first conversion unit that converts the input first input voltage to the first output voltage,
Auxiliary converter that converts the input auxiliary input voltage to auxiliary output voltage,
Is equipped with
The first conversion unit and the auxiliary conversion unit are connected between the input terminal and the output terminal.
The first conversion unit selectively switches between a first transformation state in which transformation is performed at the first transformation ratio and a second transformation state in which transformation is performed at the second transformation ratio.
The auxiliary conversion unit is a power supply device characterized in that the transformation ratio changes in association with a change in the voltage level of the auxiliary input voltage.
[Appendix 2]
The power supply device according to Appendix 1, further comprising a control unit for switching between the first transformation state and the second transformation state of the first conversion unit and changing the transformation ratio of the auxiliary conversion unit.
[Appendix 3]
The first conversion unit includes a first switching circuit, a first isolation transformer, and a first rectifier circuit.
The first switching circuit is connected to the primary side of the first isolation transformer and converts the first input voltage into an AC voltage.
The power supply device according to Appendix 2, wherein the first rectifier circuit is connected to the secondary side of the first isolation transformer and rectifies an AC voltage transformed by the first isolation transformer.
[Appendix 4]
The power supply device according to Appendix 3, wherein each of the first conversion units further includes a resonance capacitor and a resonance reactor connected in series with respect to the winding on the primary side of the first isolation transformer.
[Appendix 5]
In the first isolation transformer, an intermediate tap is connected to the winding on the secondary side of the first isolation transformer.
The power supply device according to Appendix 3 or Appendix 4, wherein the first rectifier circuit is a full-wave rectifier type using a rectifying switching element.
[Appendix 6]
A plurality of windings are connected in series on the primary side of the first isolation transformer.
The power supply device according to any one of Supplementary note 3 to Supplementary note 5, wherein a plurality of windings are connected in parallel to the secondary side of the first isolation transformer.
[Appendix 7]
In the first isolation transformer, one or more connection points are connected to the winding on the secondary side of the first isolation transformer.
The control unit changes the transformation ratio of the first isolation transformer by controlling the switching of the one or more connection points, and switches between the first transformation state and the second transformation state. The power supply device according to any one of 6.
[Appendix 8]
The first switching circuit includes a plurality of first switching elements connected in a full bridge.
Each of the plurality of first switching elements receives a first drive signal from the control unit, and performs a switching operation of switching between a conduction state and a cutoff state according to the first drive signal.
The control unit operates the first switching circuit as a half-bridge inverter by switching operation of only a part of the plurality of first switching elements to bring the first conversion unit into the first transformer state. Any of Appendix 3 to Appendix 6, which puts the first conversion unit into the second transformer state by operating the first switching circuit as a full-bridge inverter by all switching operations of the plurality of first switching elements. The power supply described in.
[Appendix 9]
The plurality of first switching elements include a first leading arm and a first trailing arm.
A leading first drive signal is input to the first leading arm from the control unit, and the first leading arm performs a switching operation in response to the leading first drive signal.
A trailing first drive signal is input to the first trailing arm from the control unit, and the first trailing arm performs a switching operation in response to the trailing first drive signal.
The control unit adjusts the phase difference between the preceding first drive signal and the trailing first drive signal, or adjusts the frequencies of the preceding first drive signal and the trailing first drive signal. The power supply device according to Appendix 8, wherein the first output voltage is adjusted.
[Appendix 10]
The power supply device according to Appendix 9, further comprising a second conversion unit that converts an input second input voltage into a second output voltage.
[Appendix 11]
The second conversion unit includes a second switching circuit, a second isolation transformer, and a second rectifier circuit.
The second switching circuit is connected to the primary side of the second isolation transformer and converts the second input voltage into an AC voltage.
The power supply device according to Appendix 10, wherein the second rectifier circuit is connected to the secondary side of the second isolation transformer and rectifies an AC voltage transformed by the second isolation transformer.
[Appendix 12]
The power supply device according to Appendix 11, wherein each of the second conversion units further includes a resonance capacitor and a resonance reactor connected in series with respect to the winding on the primary side of the second isolation transformer.
[Appendix 13]
In the second isolation transformer, an intermediate tap is connected to the winding on the secondary side of the second isolation transformer.
The power supply device according to Appendix 11 or Appendix 12, wherein the second rectifier circuit is a full-wave rectifier type using a rectifying switching element.
[Appendix 14]
A plurality of windings are connected in series on the primary side of the second isolation transformer.
The power supply device according to Appendix 11 to Appendix 13, wherein a plurality of windings are connected in parallel to the secondary side of the second isolation transformer.
[Appendix 15]
The second switching circuit includes a plurality of second switching elements connected in a half bridge.
The plurality of second switching elements are subjected to a switching operation in which a second drive signal is input from the control unit and the conduction state and the cutoff state are switched according to the second drive signal, according to any one of Appendix 11 to Appendix 14. The power supply described.
[Appendix 16]
The second conversion unit selectively switches between a third transformation state in which transformation is performed at the third transformation ratio and a fourth transformation state in which transformation is performed at the fourth transformation ratio, according to any of Appendix 11 to Appendix 14. The power supply described.
[Appendix 17]
The third transformation ratio is larger than the first transformation ratio.
The power supply device according to Appendix 16, wherein the fourth transformer ratio is larger than the second transformer ratio.
[Appendix 18]
In the second isolation transformer, one or more connection points are connected to the winding on the secondary side of the second isolation transformer.
The control unit changes the transformation ratio of the second isolation transformer by controlling the switching of the one or more connection points, and switches between the third transformation state and the fourth transformation state. The power supply device according to 17.
[Appendix 19]
The second switching circuit includes a plurality of second switching elements connected in a full bridge.
Each of the plurality of second switching elements receives a second drive signal from the control unit, and performs a switching operation of switching between a conduction state and a cutoff state according to the second drive signal.
The control unit operates the second switching circuit as a half-bridge inverter by switching operation of only a part of the plurality of second switching elements to bring the second conversion unit into the third transformer state. 16 or 17, wherein the second conversion circuit is put into the fourth transformer state by operating the second switching circuit as a full bridge inverter by all the switching operations of the plurality of second switching elements. Power supply.
[Appendix 20]
The plurality of second switching elements include a second leading arm and a second trailing arm.
The second leading arm receives a leading second drive signal from the control unit, and performs a switching operation in response to the leading second drive signal.
The second trailing arm receives a trailing second drive signal from the control unit and performs a switching operation in response to the trailing second drive signal.
The control unit adjusts the phase difference between the leading second drive signal and the trailing second drive signal, or adjusts the frequencies of the leading second drive signal and the trailing second drive signal. The power supply device according to Appendix 19, wherein the second output voltage is adjusted.
[Appendix 21]
The control unit shifts the phase of the second drive signal with respect to the phase of the first drive signal, so that the AC voltage output from the first switching circuit and the AC voltage output from the second switching circuit are output. The power supply device according to Appendix 19 or Appendix 20, which provides a phase difference from the AC voltage.
[Appendix 22]
Further, a voltage sensor for detecting the voltage level of the power supply voltage is provided.
The control unit controls switching between the first transformation state and the second transformation state of the first conversion unit based on the value detected by the voltage sensor, according to any one of Appendix 16 to Appendix 21. Power supply.
[Appendix 23]
The power supply device according to Appendix 22, wherein the control unit further controls switching between the third transformation state and the fourth transformation state of the second conversion unit based on the value detected by the voltage sensor.
[Appendix 24]
Further, a voltage sensor for detecting the voltage level of the auxiliary input voltage is provided.
The control unit controls switching between the first transformation state and the second transformation state of the first conversion unit based on the value detected by the voltage sensor, according to any one of Appendix 16 to Appendix 21. Power supply.
[Appendix 25]
The power supply device according to Appendix 24, wherein the control unit further controls switching between the third transformation state and the fourth transformation state of the second conversion unit based on the value detected by the voltage sensor.
[Appendix 26]
The first conversion unit further includes a first input capacitor that generates the first input voltage.
The second conversion unit further includes a second input capacitor that generates the second input voltage.
The auxiliary conversion unit further includes an auxiliary input capacitor that generates the auxiliary input voltage.
The power supply device according to any one of Appendix 10 to Appendix 25, wherein the first input capacitor, the second input capacitor, and the auxiliary input capacitor are connected in series to divide the power supply voltage.
[Appendix 27]
The power supply device according to Appendix 26, wherein the capacity of the auxiliary input capacitor is larger than the capacities of the first input capacitor and the second input capacitor.
[Appendix 28]
The power supply device according to Supplementary note 26 or 27, wherein the auxiliary conversion unit further includes a Zener diode connected in parallel with the auxiliary input capacitor.
[Appendix 29]
The power supply device according to any one of Supplementary note 26 to Supplementary note 28, wherein each voltage level of the first output voltage, the second output voltage, and the auxiliary output voltage is the target level.
[Appendix 30]
The control unit activates the auxiliary conversion unit before the first conversion unit and the second conversion unit when the power supply device is started, and causes the auxiliary conversion unit to start when the power supply device is stopped. The power supply device according to any one of Appendix 10 to Appendix 29, which is stopped after the first conversion unit and the second conversion unit.
[Appendix 31]
The auxiliary conversion unit includes an auxiliary switching element.
An auxiliary drive signal is input from the control unit, and the auxiliary switching element performs a switching operation of switching between a conduction state and a cutoff state according to the auxiliary drive signal.
The power supply device according to any one of Supplementary note 2 to Supplementary note 30, wherein the control unit changes the transformation ratio of the auxiliary conversion unit by controlling the duty of the auxiliary drive signal.
[Appendix 32]
The power supply device according to Appendix 31, wherein the control unit performs a switching operation of the auxiliary switching element by soft switching.
[Appendix 33]
The power supply device according to Appendix 31 or Appendix 32, wherein the auxiliary conversion unit is either a step-down converter, a step-up converter, or a buck-boost converter.
[Appendix 34]
The power supply device according to any one of Appendix 31 to Appendix 33, wherein the auxiliary conversion unit is an insulating type that is insulated between an input side and an output side.

A1, A2: Power supply device P: DC power supply LO: Load Tin: Input terminal Tout: Output terminal 1: First conversion unit 11: Switching circuit 12: Transformation circuit 13: Capacitor circuit T11a, T11b: Input terminal T12a, T12b: Output Terminal C11: Input capacitor C12: Output capacitor Q11, Q12, Q13, Q14, Q15, Q16: Switching element TR1: Insulated transformer W11: Primary winding W12, W12a, W12b: Secondary winding Lr1: Resonant reactor Cr1: Resonating capacitor 2: Second conversion unit 21: Switching circuit 22: Transformer circuit 23: Rectifier circuits T21a, T21b: Input terminals T22a, T22b: Output terminal C21: Input capacitor C22: Output capacitor Q21, Q22, Q23, Q24, Q25, Q26: Switching element TR2: Insulated transformer W21: Primary winding W22, W22a, W22b: Secondary winding Lr2: Resonant reactor Cr2: Resonant capacitor 3: Auxiliary conversion unit 31: Switching circuit T31a, T31b: Input terminal T32a, T32b: Output terminal C31: Input capacitor C32: Output capacitor Q31, Q32, Q33, Q34: Switching element D31: Diode Lr31: Reactor 4: Control unit CB1: Circuit board S1, S2: Voltage sensor

Claims (34)

A power supply device that converts the power supply voltage input from a DC power supply to a target level output voltage.
The input terminal to which the power supply voltage is applied and
The output terminal to which the output voltage is applied and
The first conversion unit that converts the input first input voltage to the first output voltage,
Auxiliary converter that converts the input auxiliary input voltage to auxiliary output voltage,
Is equipped with
The first conversion unit and the auxiliary conversion unit are connected between the input terminal and the output terminal.
The first conversion unit selectively switches between a first transformation state in which transformation is performed at the first transformation ratio and a second transformation state in which transformation is performed at the second transformation ratio.
The auxiliary conversion unit is a power supply device characterized in that the transformation ratio changes in association with a change in the voltage level of the auxiliary input voltage. It further includes a control unit for switching between the first transformation state and the second transformation state of the first conversion unit and changing the transformation ratio of the auxiliary conversion unit.
The power supply device according to claim 1. The first conversion unit includes a first switching circuit, a first isolation transformer, and a first rectifier circuit.
The first switching circuit is connected to the primary side of the first isolation transformer and converts the first input voltage into an AC voltage.
The first rectifier circuit is connected to the secondary side of the first isolation transformer and rectifies the AC voltage transformed by the first isolation transformer.
The power supply device according to claim 2. The first conversion unit further includes a resonance capacitor and a resonance reactor, each connected in series with respect to the winding on the primary side of the first isolation transformer.
The power supply device according to claim 3. In the first isolation transformer, an intermediate tap is connected to the winding on the secondary side of the first isolation transformer.
The first rectifier circuit is a full-wave rectifier type using a rectifying switching element.
The power supply device according to claim 3 or 4. A plurality of windings are connected in series on the primary side of the first isolation transformer.
A plurality of windings are connected in parallel on the secondary side of the first isolation transformer.
The power supply device according to any one of claims 3 to 5. In the first isolation transformer, one or more connection points are connected to the winding on the secondary side of the first isolation transformer.
By controlling the switching of the one or more connection points, the control unit changes the transformation ratio of the first isolation transformer and switches between the first transformation state and the second transformation state.
The power supply device according to any one of claims 3 to 6. The first switching circuit includes a plurality of first switching elements connected in a full bridge.
Each of the plurality of first switching elements receives a first drive signal from the control unit, and performs a switching operation of switching between a conduction state and a cutoff state according to the first drive signal.
The control unit operates the first switching circuit as a half-bridge inverter by switching operation of only a part of the plurality of first switching elements to bring the first conversion unit into the first transformer state. By operating the first switching circuit as a full bridge inverter by all the switching operations of the plurality of first switching elements, the first conversion unit is brought into the second transformer state.
The power supply device according to any one of claims 3 to 6. The plurality of first switching elements include a first leading arm and a first trailing arm.
A leading first drive signal is input to the first leading arm from the control unit, and the first leading arm performs a switching operation in response to the leading first drive signal.
A trailing first drive signal is input to the first trailing arm from the control unit, and the first trailing arm performs a switching operation in response to the trailing first drive signal.
The control unit adjusts the phase difference between the preceding first drive signal and the trailing first drive signal, or adjusts the frequencies of the preceding first drive signal and the trailing first drive signal. Then, the first output voltage is adjusted.
The power supply device according to claim 8. It further includes a second converter that converts the input second input voltage into a second output voltage.
The power supply device according to claim 9. The second conversion unit includes a second switching circuit, a second isolation transformer, and a second rectifier circuit.
The second switching circuit is connected to the primary side of the second isolation transformer and converts the second input voltage into an AC voltage.
The second rectifying circuit is connected to the secondary side of the second isolation transformer and rectifies the AC voltage transformed by the second isolation transformer.
The power supply device according to claim 10. The second converter further comprises a resonant capacitor and a resonant reactor, each connected in series with respect to the primary winding of the second isolation transformer.
The power supply device according to claim 11. In the second isolation transformer, an intermediate tap is connected to the winding on the secondary side of the second isolation transformer.
The second rectifier circuit is a full-wave rectifier type using a rectifying switching element.
The power supply device according to claim 11 or 12. A plurality of windings are connected in series on the primary side of the second isolation transformer.
A plurality of windings are connected in parallel on the secondary side of the second isolation transformer.
The power supply device according to claim 11 to 13. The second switching circuit includes a plurality of second switching elements connected in a half bridge.
The plurality of second switching elements receive a second drive signal from the control unit, and perform a switching operation in which a conduction state and a cutoff state are switched according to the second drive signal.
The power supply device according to any one of claims 11 to 14. The second conversion unit selectively switches between a third transformation state in which transformation is performed at the third transformation ratio and a fourth transformation state in which transformation is performed at the fourth transformation ratio.
The power supply device according to any one of claims 11 to 14. The third transformation ratio is larger than the first transformation ratio.
The fourth transformation ratio is larger than the second transformation ratio.
The power supply device according to claim 16. In the second isolation transformer, one or more connection points are connected to the winding on the secondary side of the second isolation transformer.
By controlling the switching of the one or more connection points, the control unit changes the transformation ratio of the second isolation transformer and switches between the third transformation state and the fourth transformation state.
The power supply device according to claim 16 or 17. The second switching circuit includes a plurality of second switching elements connected in a full bridge.
Each of the plurality of second switching elements receives a second drive signal from the control unit, and performs a switching operation of switching between a conduction state and a cutoff state according to the second drive signal.
The control unit operates the second switching circuit as a half-bridge inverter by switching operation of only a part of the plurality of second switching elements to bring the second conversion unit into the third transformer state. By operating the second switching circuit as a full bridge inverter by all the switching operations of the plurality of second switching elements, the second conversion unit is brought into the fourth transformer state.
The power supply device according to claim 16 or 17. The plurality of second switching elements include a second leading arm and a second trailing arm.
The second leading arm receives a leading second drive signal from the control unit, and performs a switching operation in response to the leading second drive signal.
The second trailing arm receives a trailing second drive signal from the control unit and performs a switching operation in response to the trailing second drive signal.
The control unit adjusts the phase difference between the leading second drive signal and the trailing second drive signal, or adjusts the frequencies of the leading second drive signal and the trailing second drive signal. Then, the second output voltage is adjusted.
The power supply device according to claim 19. The control unit shifts the phase of the second drive signal with respect to the phase of the first drive signal, so that the AC voltage output from the first switching circuit and the AC voltage output from the second switching circuit are output. Provide a phase difference with the AC voltage,
The power supply according to claim 19 or 20. Further, a voltage sensor for detecting the voltage level of the power supply voltage is provided.
The control unit controls switching between the first transformation state and the second transformation state of the first conversion unit based on the value detected by the voltage sensor.
The power supply device according to any one of claims 16 to 21. The control unit further controls switching between the third transformation state and the fourth transformation state of the second conversion unit based on the value detected by the voltage sensor.
The power supply device according to claim 22. Further, a voltage sensor for detecting the voltage level of the auxiliary input voltage is provided.
The control unit controls switching between the first transformation state and the second transformation state of the first conversion unit based on the value detected by the voltage sensor.
The power supply device according to any one of claims 16 to 21. The control unit further controls switching between the third transformation state and the fourth transformation state of the second conversion unit based on the value detected by the voltage sensor.
The power supply device according to claim 24. The first conversion unit further includes a first input capacitor that generates the first input voltage.
The second conversion unit further includes a second input capacitor that generates the second input voltage.
The auxiliary conversion unit further includes an auxiliary input capacitor that generates the auxiliary input voltage.
The first input capacitor, the second input capacitor, and the auxiliary input capacitor are connected in series to divide the power supply voltage.
The power supply device according to any one of claims 10 to 25. The capacity of the auxiliary input capacitor is larger than the capacities of the first input capacitor and the second input capacitor.
The power supply device according to claim 26. The auxiliary converter further includes a Zener diode connected in parallel with the auxiliary input capacitor.
The power supply device according to claim 26 or 27. Each voltage level of the first output voltage, the second output voltage, and the auxiliary output voltage is the target level.
The power supply device according to any one of claims 26 to 28. The control unit activates the auxiliary conversion unit before the first conversion unit and the second conversion unit when the power supply device is started, and causes the auxiliary conversion unit to start when the power supply device is stopped. Stop after the first conversion unit and the second conversion unit,
The power supply device according to any one of claims 10 to 29. The auxiliary conversion unit includes an auxiliary switching element.
The auxiliary switching element receives an auxiliary drive signal from the control unit, and performs a switching operation of switching between a conduction state and a cutoff state according to the auxiliary drive signal.
The control unit changes the transformation ratio of the auxiliary conversion unit by controlling the duty of the auxiliary drive signal.
The power supply device according to any one of claims 2 to 30. The control unit performs the switching operation of the auxiliary switching element by soft switching.
The power supply device according to claim 31. The auxiliary conversion unit is either a step-down converter, a step-up converter, or a buck-boost converter.
The power supply device according to claim 31 or 32. The auxiliary conversion unit is an insulated type that is insulated between the input side and the output side.
The power supply device according to any one of claims 31 to 33.

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