Multi-terminal switched mode power supply converter, power supply and power supply conversion system

Abstract

The embodiment of the application discloses a multi-end switching power supply converter, a power supply and a power supply conversion system, the converter comprises a power tube conversion circuit and a power tube driving circuit; the power tube conversion circuit comprises a first switch tube, a second switch tube, a third switch tube and a first diode, the first switch tube and the second switch tube constitute a first bridge arm, and the third switch tube and the first diode constitute a second bridge arm; the first bridge arm is connected in parallel with the second bridge arm, and the middle node of the first bridge arm and the second bridge arm is connected with an output end load; the anode of the first diode is connected with the third switch tube, and the cathode of the first diode is connected with the parallel end of the second bridge arm and the first bridge arm; the power tube driving circuit is used for driving the on-off of each switch tube in the power tube conversion circuit according to a working mode. The embodiment of the application realizes the compatibility of a half-bridge type converter architecture and a double-tube forward type converter architecture on one power supply converter, and has good practicability.

Description

Multi-terminal switching power converters, power supplies and power conversion systems Technical Field

[0001] This application relates to the field of power supply, and more particularly to a multi-terminal switching power converter, power supply, and power conversion system. Background Technology

[0002] Switching power supplies, as an emerging energy provider, are widely used in various industrial energy fields to convert alternating current (AC) into direct current (DC) to supply power to load devices.

[0003] Among the many switching power supply circuit topologies, the bidirectional converter circuit includes the half-bridge converter. Its simple circuit structure, input-output electrical isolation, low output voltage ripple, and high conversion efficiency have made it widely popular in the industry. However, because the half-bridge converter circuit requires both high-side and low-side drive, it leads to the problem of simultaneous conduction of the control switching transistors. Consequently, under high-frequency, high-current load conditions, traditional half-bridge power converters are prone to burnout due to the Miller effect between the upper and lower transistors, resulting in common conduction of the switching transistors and thus lower circuit safety. Summary of the Invention

[0004] In view of this, in order to solve the problems of the prior art, this application provides a multi-terminal switching power converter, power supply and power conversion system.

[0005] In a first aspect, this application provides a multi-terminal switching power converter, including a power transistor conversion circuit and a power transistor driving circuit;

[0006] The power transistor conversion circuit includes a first switch, a second switch, a third switch, and a first diode. The first switch and the second switch form a first bridge arm, and the third switch and the first diode form a second bridge arm.

[0007] The first bridge arm is connected in parallel with the second bridge arm, and the middle node between the first bridge arm and the second bridge arm is connected to the output load.

[0008] The anode of the first diode is connected to the third switch, and the cathode of the first diode is connected to the parallel terminal of the second bridge arm and the first bridge arm.

[0009] The power transistor drive circuit is used to drive the switching of each switch in the power transistor conversion circuit according to the operating mode.

[0010] In an optional implementation, if the operating mode is to control the second switch to be in a normally closed state, then the power transistor drive circuit is used to isolate the switching on and off of the second switch and the third switch.

[0011] If the operating mode is to control the third switch to be in a normally closed state, then the power transistor drive circuit is used to isolate the switching on and off of the first switch and the second switch.

[0012] In an optional implementation, the power transistor conversion circuit further includes a transformer module;

[0013] The transformer module includes a first transformer, a second diode, a third diode, a fourth diode, and a fifth diode;

[0014] The input terminal of the first transformer is connected to the first terminals of the second diode and the third diode respectively, the second terminal of the second diode is connected in series with the first terminal of the fourth diode, and the second terminal of the fourth diode is grounded;

[0015] The second terminal of the third diode is connected in series with the first terminal of the fifth diode, and the second terminal of the fifth diode is grounded.

[0016] In an optional implementation, the power transistor conversion circuit further includes a first resistor, a second resistor, and a third resistor;

[0017] The gates of the first switch, the second switch, and the third switch are each connected to a first resistor. A second resistor is connected in parallel between the gate and source of the first switch, the second switch, and the third switch. A third resistor is connected in parallel between the second resistor and the third resistor.

[0018] In an optional embodiment, the power transistor conversion circuit further includes a first capacitor and a second capacitor;

[0019] One end of the first capacitor is connected to the positive terminal of the input terminal, and the other end of the first capacitor is grounded;

[0020] One end of the second capacitor is connected to the parallel terminal of the second bridge arm and the first bridge arm, and the other end of the second capacitor is grounded.

[0021] In an optional implementation, the power transistor drive circuit includes two drive topology modules with identical structures;

[0022] The drive topology module includes a PWM signal output unit, a first-stage amplification unit, a transformer unit, a second-stage amplification unit, and a drive unit;

[0023] The PWM signal output unit is used to output PWM signals;

[0024] The first-stage amplification unit amplifies the PWM signal, which is then amplified by the transformer unit and input to the second-stage amplification unit before being input to the drive unit.

[0025] The driving unit is used to isolate the switching on and off of each switching transistor in the power transistor conversion circuit.

[0026] In an optional embodiment, the first-stage amplification unit includes a fourth resistor, a fifth resistor, and a first amplification chip; the fourth resistor and the fifth resistor are connected in parallel and then connected to the first amplification chip;

[0027] The secondary amplification unit includes a sixth resistor, a seventh resistor, and a second amplification chip; the second amplification chip is connected to one end of the sixth resistor and the seventh resistor, respectively; the other end of the sixth resistor and the seventh resistor are both connected to the driving unit.

[0028] In an optional embodiment, the transformer unit includes a second transformer, a third capacitor, an eighth resistor, a ninth resistor, a tenth resistor, and a fourth capacitor;

[0029] One end of the third capacitor is connected to one end of the eighth resistor, the other end of the eighth resistor is connected to the first input terminal of the second transformer, and the other end of the third capacitor is connected to the first-stage amplification unit.

[0030] The ninth resistor is disposed between the third capacitor and the second input terminal of the second transformer;

[0031] One end of the fourth capacitor is connected to the first output terminal of the second transformer, and the other end of the fourth capacitor is connected to one end of the tenth resistor and the second-stage amplification unit, respectively.

[0032] The other end of the tenth resistor is connected to the second output terminal of the second transformer.

[0033] Secondly, this application provides a power supply, including the aforementioned multi-terminal switching power converter.

[0034] Thirdly, this application provides a power conversion system, including the power supply as described above.

[0035] The embodiments of this application have the following beneficial effects:

[0036] This application provides a multi-terminal switching power converter that uses three switching transistors to form two bridge arms. The power transistor drive circuit is isolated and drives the switching of each transistor through operating mode control, forming a half-bridge or two-transistor forward converter architecture. This allows for alternating switching between the two architectures in a three-terminal switching power converter. Because this application is compatible with both half-bridge and two-transistor forward converter architectures, it can switch to a two-transistor forward converter architecture to input high-frequency, high-current signals to the load. This overcomes the defect of traditional half-bridge power converters where transistors burn out due to the Miller effect. Furthermore, the multi-terminal switching power converter of this embodiment can achieve independent adjustment of the drive pulse width in each direction of the bidirectional power converter in non-isolated applications, demonstrating good practicality. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be considered as a limitation on the scope of protection of this application. In the various drawings, similar components are numbered similarly.

[0038] Figure 1 shows a schematic diagram of the structure of the multi-terminal switching power converter in an embodiment of this application;

[0039] Figure 2 shows a first structural schematic diagram of the power transistor conversion circuit in an embodiment of this application;

[0040] Figure 3 shows a second structural schematic diagram of the power transistor conversion circuit in an embodiment of this application;

[0041] Figure 4 shows a schematic diagram of the driving topology module in the power transistor driving circuit of this application embodiment;

[0042] Figure 5 shows a schematic diagram of the power transistor drive circuit in an embodiment of this application. Detailed Implementation

[0043] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0044] The components of the embodiments of this application described and illustrated in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0045] In the following, the terms “comprising,” “having,” and their cognates, which may be used in various embodiments of this application, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as excluding, firstly, the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations thereof.

[0046] Furthermore, the terms "first," "second," and "third" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0047] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this application pertain. Terms (such as those defined in a generally used dictionary) shall be interpreted as having the same meaning as in their contextual meaning in the relevant technical field and shall not be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of this application.

[0048] PWM signal: refers to pulse width modulation; pulse width modulation is an analog control method that modulates the bias of the base of a transistor or the gate of a MOSFET according to the change of the corresponding load in the circuit, thereby changing the conduction time of the transistor or MOSFET and thus changing the output of the switching power supply.

[0049] Example

[0050] Referring to Figure 1, this application embodiment provides a multi-terminal switching power converter, including a power transistor conversion circuit 10 and a power transistor drive circuit 20.

[0051] As an example, referring to Figure 2, the power transistor conversion circuit 10 includes a first switch Q1, a second switch Q2, a third switch Q3, and a first diode D1. The first switch Q1 and the second switch Q2 form a first bridge arm, and the third switch Q3 and the first diode D1 form a second bridge arm. The first bridge arm is connected in parallel with the second bridge arm, and the intermediate node of the first bridge arm and the second bridge arm is connected to the output load. The anode of the first diode D1 is connected to the third switch Q3, and the cathode of the first diode D1 is connected to the parallel terminal of the second bridge arm and the first bridge arm.

[0052] In one embodiment, the power transistor conversion circuit 10 further includes a first capacitor C1 and a second capacitor C2; one end of the first capacitor C1 is connected to the positive terminal of the input, and the other end of the first capacitor C1 is grounded; one end of the second capacitor C2 is connected to the parallel terminal of the second bridge arm and the first bridge arm, and the other end of the second capacitor C2 is grounded. Both the first capacitor C1 and the second capacitor C2 are electrolytic capacitors. Electrolytic capacitors have large capacitance and low manufacturing cost, and can be used for power supply filtering.

[0053] The power transistor converter circuit 10 receives electrical signals through two input terminals (IN+ and IN- as shown in Figure 2). The power transistor driver circuit 20 drives the switching of each switch in the power transistor converter circuit 10 according to the operating mode, thereby controlling the conduction and cutoff of the current in the power transistor converter circuit 10. The power transistor converter circuit 10 outputs electrical signals to the connected load through two output terminals (OUT- and OUT+ as shown in Figure 2) to provide the required current and voltage to the load.

[0054] In one embodiment, if the operating mode is to control the second switch Q2 to be in the normally closed state, the power transistor drive circuit 20 is used to isolate the switching on and off of the first switch Q1 and the third switch Q3, so that the power transistor conversion circuit 10 presents an operating mode in the forward topology operation state.

[0055] In one embodiment, if the operating mode is to control the third switch Q3 to be in the normally closed state, the power transistor drive circuit 20 is used to isolate the switching of the first switch Q1 and the second switch Q2, so that the power transistor conversion circuit 10 presents an operating mode in a half-bridge topology.

[0056] The switching control between the forward topology and half-bridge topology operating modes depends on the characteristics of the connected load and is either automatically set or manually set based on demand. These two operating modes generally cannot operate simultaneously, thereby improving the versatility of multi-terminal switching power supply converters.

[0057] Referring also to Figure 3, in one embodiment, the power transistor conversion circuit 10 further includes a first resistor (R1, R2, R3 in Figure 3), a second resistor (R4, R5, R6 in Figure 3), and a third resistor (R7, R8, R9 in Figure 3).

[0058] The gates of the first switch Q1, the second switch Q2, and the third switch Q3 are each connected to a first resistor. A second resistor is connected in parallel between the gate and source of the first switch Q1, the second switch Q2, and the third switch Q3. A third resistor is connected in parallel between the second resistor and the third resistor.

[0059] As shown in Figure 3, in practical applications, the power transistor conversion circuit 10 also includes a connection circuit, which includes multiple sockets and multiple capacitors or resistors connected to each socket. The number of sockets and the number of capacitors and resistors connected to each socket are not limited here.

[0060] Optionally, the connection circuit includes three sockets, such as sockets P1, P2, and P3. Socket P1 is connected to socket P2 via a first pin (pin 1 of socket P1 in Figure 3), and socket P1 is connected to socket P3 via a second pin (pin 2 of socket P1 in Figure 3). The first and second pins are respectively connected to the fifth capacitor C7 and the sixth capacitor C8 connected in parallel; wherein the fifth capacitor C7 is an electrolytic capacitor; the first pin is also used for grounding. The two pins of socket P3 are connected to the second pin of socket P1 via the eleventh resistor R10 and the twelfth resistor R11 connected in parallel, wherein one end of the twelfth resistor R11 is used to connect to the high-power current output terminal.

[0061] The parallel connection of the first and third resistors is connected to socket P2, which is also used to connect to the output terminal (OUT+). This embodiment does not limit the number of pins in sockets P1, P2, and P3, nor does it limit the pin numbers and connection methods between each socket and each component.

[0062] The power transistor conversion circuit 10 is connected to an external circuit or device via sockets P1, P2, and P3. For example, the power transistor conversion circuit 10 is connected to the power transistor driver circuit 20 via socket P2 to receive the PWM signal output by the power transistor driver circuit 20. This PWM signal is used to drive the switching of the first switch Q1, the second switch Q2, and the third switch Q3.

[0063] In one embodiment, the power transistor conversion circuit 10 further includes a transformer module; the transformer module includes a first transformer T1, a second diode D2, a third diode D3, a fourth diode D4, and a fifth diode D5.

[0064] The input terminals of the first transformer T1 are connected to the first terminals of the second diode D2 and the third diode D3 respectively. The second terminal of the second diode D2 is connected in series with the first terminal of the fourth diode D4, and the second terminal of the fourth diode D4 is grounded. The second terminal of the third diode D3 is connected in series with the first terminal of the fifth diode D5, and the second terminal of the fifth diode D5 is grounded.

[0065] Furthermore, the cathodes of the third diode D3 and the second diode D2 are both connected to the high-power current output terminal (the Imax2 terminal in Figure 3) through the thirteenth resistor R12; the anode of the third diode D3 is connected to the first input terminal of the first transformer T1 and the cathode of the fifth diode D5 respectively; the anode of the fifth diode D5 is grounded; the anode of the second diode D2 is connected to the second input terminal of the first transformer T1 and the cathode of the fourth diode D4 respectively; optionally, the transformer module also includes a fourteenth resistor R13, which is connected to the first input terminal and the second input terminal of the first transformer T1 respectively.

[0066] The first output terminal of the first transformer T1 is connected to the first diode D1 and the third switch Q3 respectively. The second output terminal of the first transformer T1 is connected to the load through the output terminal (OUT- terminal in Figure 3).

[0067] In this embodiment, when the power transistor converter circuit 10 is in the operating mode corresponding to the half-bridge topology, it drives the load in isolation through the first transformer T1; when the power transistor converter circuit 10 is in the operating mode corresponding to the forward topology, it drives the non-isolated load directly; thus, the multi-terminal switching power supply converter is compatible with the two application requirements of driving the load directly without isolation and driving the load in isolation through the transformer, and realizes the automatic adjustment of the drive pulse width in each direction of the multi-terminal switching power supply converter.

[0068] Furthermore, the power transistor drive circuit 20 includes two identical drive topology modules; as shown in Figure 4, the drive topology module includes a PWM signal output unit 21, a first-stage amplifier unit 22, a transformer unit 23, a second-stage amplifier unit 24, and a drive unit 25; the PWM signal output unit 21 is used to output a PWM signal; the first-stage amplifier unit 22 is used to amplify the PWM signal, which is then amplified by the transformer unit 23 and input to the second-stage amplifier unit 24 before being input to the drive unit 25; the drive unit 25 is used to isolate the switching on and off of each switch in the power transistor conversion circuit 10.

[0069] Referring to Figures 4 and 5 together, in one embodiment, the PWM signal output unit 21 is used to output PWM signals; optionally, the PWM signal output unit 21 includes at least two sockets, such as sockets P4 and P5 in Figure 5, and inputs two PWM signals to the power transistor drive circuit 20 through sockets P4 and P5 respectively.

[0070] In one embodiment, the first-stage amplification unit 22 includes a fourth resistor (R14 or R15 in Figure 5), a fifth resistor (R16 or R17 in Figure 5), and a first amplification chip (U1 or U2 in Figure 5); the fourth and fifth resistors are connected in parallel and then connected to the first amplification chip. The second-stage amplification unit 24 is a second amplification chip (U3 or U4 in Figure 5). The two pins of the P4 and P5 sockets are connected to the fourth and fifth resistors, respectively; the first amplification chip is also used to connect to a voltage source (the 12VS power supply terminal in Figure 5).

[0071] In one embodiment, the transformer unit 23 includes a second transformer (T2 or T3 in Figure 3), a third capacitor (C3 or C4 in Figure 5), an eighth resistor (R18 or R19 in Figure 5), a ninth resistor (R20 or R21 in Figure 5), a tenth resistor (R22 or R23 in Figure 5), and a fourth capacitor (C5 or C6 in Figure 5).

[0072] In each group of drive topology modules, one end of the third capacitor is connected to one end of the eighth resistor, the other end of the eighth resistor is connected to the first input terminal of the second transformer, and the other end of the third capacitor is connected to the first-stage amplification unit 22; the ninth resistor is set between the third capacitor and the second input terminal of the second transformer; one end of the fourth capacitor is connected to the first output terminal of the second transformer, and the other end of the fourth capacitor is connected to one end of the tenth resistor and the second-stage amplification unit 24 respectively; the other end of the tenth resistor is connected to the second output terminal of the second transformer.

[0073] The secondary amplification unit 24 includes a sixth resistor (R24 or R25 in Figure 5), a seventh resistor (R26 or R27 in Figure 5), and a second amplification chip (U3 or U4 in Figure 5); the second amplification chip is connected to one end of the sixth resistor and the seventh resistor respectively; the other end of the sixth resistor and the seventh resistor are both connected to the driving unit 25.

[0074] Specifically, the P4 and P5 sockets respectively input two PWM signals. After being amplified and driven by the U1 and U2 chips, the signals drive the isolation transformers T1 and T2 and are then transmitted to the U3 and U4 signal chips for amplification and driving. Each drive topology module drives the three switching transistors Q1, Q2, and Q3 in the power transistor conversion circuit 10 through two sets of identical and independent totem pole structure drive units 25.

[0075] In this embodiment, the power transistor drive circuit 20 drives and controls the three switching transistors Q1, Q2, and Q3 in the power transistor conversion circuit 10 to turn on and off, so that the power transistor conversion circuit 10 presents different operating modes.

[0076] Optionally, a set of totem-pole structure drive units 25 includes a fourth switch (Q4 or Q5 as shown in Figure 5), a fifth switch (Q6 or Q7 as shown in Figure 5), and a fifteenth resistor (R28 or R29 as shown in Figure 5); the first terminal of the fourth switch is connected to a voltage source (the 12VS power supply terminal in Figure 5), the second terminal of the fourth switch is connected to one end of the fifteenth resistor and the secondary amplifier unit 24, the third terminal of the fourth switch is connected to the first terminal of the fifth switch; the second terminal of the fifth switch is connected to one end of the fifteenth resistor and the secondary amplifier unit 24; and the third terminal of the fifth switch is connected to the other end of the fifteenth resistor. Optionally, the third terminal of the fifth switch in at least one set of drive units 25 is grounded.

[0077] Optionally, the fourth switching transistor is an NPN transistor; the fifth switching transistor is a PNP transistor.

[0078] Optionally, the power transistor drive circuit 20 further includes a power supply protection unit 26, which includes a socket (P6 socket as shown in Figure 5), a seventh capacitor C9, a sixth diode D6, and a seventh diode D7; the first pin of the P6 socket (pin 9 as shown in Figure 5) is connected to the high-power current input terminal; the anode of the sixth diode D6 is connected to the high-power current input terminal and is used to supply power to the P6 socket through the high-power current input terminal, and the cathode of the sixth diode D6 is connected to the P6 socket and the voltage source respectively; the seventh diode D7 is connected in parallel with the seventh capacitor C9, and the two parallel terminals of the seventh diode D7 and the seventh capacitor C9 (the first parallel terminal and the second parallel terminal) are respectively connected to the two pins of the P6 socket; the first parallel terminal of the seventh diode D7 and the seventh capacitor C9 is used to connect to the high-power current input terminal, and the second parallel terminal is grounded.

[0079] The two sets of totem pole structure drive units 25 are respectively connected to the power supply protection unit 26. The power supply protection unit 26 is used to supply power to the power transistor drive circuit 20 and to provide current protection during power supply. Specifically, the emitter of the fourth switch transistor and the collector of the fifth switch transistor are respectively connected to the P6 socket.

[0080] The power transistor drive circuit 20 is connected to the power transistor converter circuit 10 through the P6 socket. It is used to input PWM signals to the power transistor converter circuit 10 to drive and control the switching of each switching transistor in the power transistor converter circuit 10, thereby realizing the switching of the topology of the multi-terminal switching power converter.

[0081] In this embodiment, the switching of the topology of the multi-terminal switching power converter is digitally controlled by different software programs.

[0082] If the first switch Q1 is controlled to be in the normally closed state, the second switch Q2 and the third switch Q3 in the multi-terminal switching power converter and their connected circuits form a half-bridge converter topology. The power transistor drive circuit 20 can output a PWM signal to isolate the switching on and off of the second switch Q2 and the third switch Q3.

[0083] If the third switch Q3 is controlled to be in the normally closed state, the first switch Q1 and the second switch Q2 in the multi-terminal switching power converter and their connected circuit parts form a two-transistor forward converter topology. The power transistor drive circuit 20 can output a PWM signal to isolate the switching on and off of the first switch Q1 and the second switch Q2.

[0084] This application embodiment also provides a power supply, which includes the multi-terminal switching power converter described above. The power supply in this embodiment corresponds to the multi-terminal switching power converter described above; any options of the multi-terminal switching power converter described above are also applicable to the power supply in this embodiment, and will not be described in detail here.

[0085] This application also provides a power conversion system, including the power supply described above, for converting AC power into DC power to supply external load devices. The power conversion system in this embodiment corresponds to the power supply described above; any alternatives to the power supply described above are also applicable to the power conversion system of this embodiment, and will not be detailed here.

[0086] The multi-terminal switching power converter provided in this application embodiment uses three switching transistors to form two bridge arms. The power transistor drive circuit 20 is used to isolate and drive the switching of each switching transistor to form a half-bridge or dual-transistor forward converter architecture. In this embodiment, firstly, different power converter architectures can be switched according to the current requirements of the connected load. This allows for the input of high-frequency, high-current power to the load by switching to a two-transistor forward converter architecture, overcoming the defect of traditional half-bridge power converters burning out due to the Miller effect between the upper and lower transistors under high-frequency, high-current load conditions. Secondly, it achieves complete compatibility between two application requirements: direct non-isolated load driving and load driving through transformer isolation, improving the versatility of the bidirectional power converter. Thirdly, by switching between a half-bridge converter architecture and a two-transistor forward converter architecture, it can possess all the functions of a full-bridge converter architecture, and its reliability is higher compared to a full-bridge converter architecture. Fourthly, this embodiment achieves high-frequency direct driving of non-isolated loads and can have a natural reverse negative voltage pulse output under heavy load conditions. Furthermore, the structure of the switching power converter is simple, thereby reducing the production cost of the switching power converter.

[0087] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A multi-terminal switching power supply converter, characterized in that, The system includes a power transistor conversion circuit and a power transistor drive circuit. The power transistor conversion circuit includes a first switch, a second switch, a third switch, and a first diode. The first switch and the second switch form a first bridge arm, and the third switch and the first diode form a second bridge arm. The first bridge arm is connected in parallel with the second bridge arm, and the intermediate node between the first bridge arm and the second bridge arm is connected to the output load. The anode of the first diode is connected to the third switch, and the cathode of the first diode is connected to the parallel terminal of the second bridge arm and the first bridge arm. The power transistor drive circuit is used to drive the switching of each switch in the power transistor conversion circuit according to the operating mode. The power transistor drive circuit includes two identical drive topology modules. The drive topology module includes a PWM signal output unit, a first-stage amplification unit, a transformer unit, and a second... The circuit comprises a first-stage amplification unit and a driving unit; the PWM signal output unit is used to output a PWM signal; the first-stage amplification unit amplifies the PWM signal, which is then input to the second-stage amplification unit after being amplified by the transformer unit, and finally input to the driving unit; the driving unit is a totem pole structure used to isolate the switching of each switch in the power transistor conversion circuit; if the operating mode is to control the second switch to be normally closed, the power transistor conversion circuit is a forward converter topology, and the power transistor driving circuit is used to isolate the switching of the first switch and the third switch; if the operating mode is to control the third switch to be normally closed, the power transistor conversion circuit is a half-bridge converter topology, and the power transistor driving circuit is used to isolate the switching of the first switch and the second switch.

2. The multi-terminal switching power supply converter according to claim 1, characterized in that, The power transistor conversion circuit further includes a transformer module; the transformer module includes a first transformer, a second diode, a third diode, a fourth diode, and a fifth diode; the input terminal of the first transformer is connected to the first terminals of the second diode and the third diode respectively, the second terminal of the second diode is connected in series with the first terminal of the fourth diode, and the second terminal of the fourth diode is grounded; the second terminal of the third diode is connected in series with the first terminal of the fifth diode, and the second terminal of the fifth diode is grounded.

3. The multi-terminal switching power supply converter according to claim 1, characterized in that, The power transistor conversion circuit further includes a first resistor, a second resistor, and a third resistor; the gates of the first switch, the second switch, and the third switch are each connected to a first resistor, a second resistor is connected in parallel between the gates and sources of the first switch, the second switch, and the third switch, and a third resistor is connected in parallel between the second resistor and the first resistor.

4. The multi-terminal switching power supply converter according to claim 1, characterized in that, The power transistor conversion circuit also includes a first capacitor and a second capacitor; one end of the first capacitor is connected to the positive terminal of the input terminal, and the other end of the first capacitor is grounded; one end of the second capacitor is connected to the parallel terminal of the second bridge arm and the first bridge arm, and the other end of the second capacitor is grounded.

5. The multi-terminal switching power supply converter according to claim 1, characterized in that, The first-stage amplification unit includes a fourth resistor, a fifth resistor, and a first amplification chip; the fourth resistor and the fifth resistor are connected in parallel and then connected to the first amplification chip; the second-stage amplification unit includes a sixth resistor, a seventh resistor, and a second amplification chip; the second amplification chip is connected to one end of the sixth resistor and the seventh resistor respectively; the other ends of the sixth resistor and the seventh resistor are both connected to the driving unit.

6. The multi-terminal switching power supply converter according to claim 1, characterized in that, The transformer unit includes a second transformer, a third capacitor, an eighth resistor, a ninth resistor, a tenth resistor, and a fourth capacitor; one end of the third capacitor is connected to one end of the eighth resistor, the other end of the eighth resistor is connected to the first input terminal of the second transformer, and the other end of the third capacitor is connected to the first-stage amplification unit; the ninth resistor is disposed between the third capacitor and the second input terminal of the second transformer; one end of the fourth capacitor is connected to the first output terminal of the second transformer, and the other end of the fourth capacitor is connected to one end of the tenth resistor and the second-stage amplification unit. The other end of the tenth resistor is connected to the second output terminal of the second transformer.

7. A power supply, characterized in that, Including the multi-terminal switching power converter as described in any one of claims 1-6.

8. A power conversion system, characterized in that, Includes the power supply as described in claim 7.

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