Power conversion circuit, power supply module based on power conversion circuit and control method and starting method of power conversion circuit

Abstract

The invention discloses a power conversion circuit, a power module based on the power conversion circuit and a control method and a starting method of the power conversion circuit. The power conversion circuit comprises a Vin, a GND, a near-end power conversion unit and a far-end power conversion unit, wherein the near-end power conversion unit and the far-end power conversion unit are connected between the Vin and the GND in parallel. The near-end power conversion unit comprises S1, S2 and Q1 which are connected in series; the far-end power conversion unit comprises S4, S3 and Q2 which are connected in series; the dotted terminal of the first high-side winding P1 is connected with the node L1, and the synonym terminal of the P1 is connected with one end of the resonant capacitor bank; the other end of the resonant capacitor bank is connected with the dotted terminal of the second high-side winding P2, and the synonym terminal of the P2 is connected with the node R1; the dotted terminal of the first low-side winding T1 is connected with the node L2, the synonym terminal of the T1 is connected with the dotted terminal of the second low-side winding T2, and the synonym terminal of the T2 is connected with the node R2; an output terminal Vo is connected to a connecting line between the first low-side winding T1 and the second low-side winding T2; the input capacitor is arranged between the Vin and the GND or between the Vin and the Vo; and the output capacitor Co is arranged between the Vo and the GND.

Description

Technical Field

[0001] The present invention relates to a power conversion circuit, a power supply module based thereon, and a control method and a startup method thereof. Background Art

[0002] The rapid development of technologies such as artificial intelligence (AI) and large language models (LLMs) has accelerated the power supply demand of data centers. The power demand of AI chips (such as GPUs, TPUs, ASICs) is increasing. For example, the power of NVIDIA's GPU chips has increased from 300W of A100 to 700W of H100. Considering the limited board area, the sudden increase in the power of AI chips poses higher requirements for the power density and efficiency of the chip power supply. The intermediate bus architecture is the mainstream architecture of the on-board power supply for AI chips at present, including a front-stage bus converter that provides a fixed voltage ratio (such as 4:1, 8:1), and a rear-stage multi-phase voltage regulation module. The Open Computing Project (OCP) internationally has formulated relevant standards for the on-board power supply of AI chips, and has put forward strict requirements for the size and efficiency of the bus converter. The 4:1 intermediate bus architecture is the preferred solution for current AI chip manufacturers. Therefore, under the limited standard size, how to further improve the output power, efficiency, and power density of the 4:1 bus converter to meet the needs of the next-generation AI chips is an urgent problem to be solved. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a high-power power conversion circuit for powering the next-generation AI chips.

[0004] To solve the above technical problem, the technical solution adopted by the present invention is: a power conversion circuit, comprising an input terminal Vin and a ground terminal GND, a proximal power conversion unit and a distal power conversion unit connected in parallel between the input terminal Vin and the ground terminal GND; the proximal power conversion unit includes a first main control switch S1, a second main control switch S2, and a first synchronous rectification switch Q1 connected in series; the distal power conversion unit includes a fourth main control switch S4, a third main control switch S3, and a second synchronous rectification switch Q2 connected in series; the connection node of the first main control switch S1 and the second main control switch S2 is denoted as L1, and the connection node of the second main control switch S2 and the first synchronous rectification switch Q1 is denoted as L2; the connection node of the fourth main control switch S4 and the third main control switch S3 is denoted as R1, and the connection node of the third main control switch S3 and the second synchronous rectification switch Q2 is denoted as R2;

[0005] The same-name terminal of the first high-side winding P1 is connected to the node L1, and the different-name terminal of the first high-side winding P1 is connected to one end of the resonant capacitor bank Cr; the other end of the resonant capacitor bank Cr is connected to the same-name terminal of the second high-side winding P2, and the different-name terminal of the second high-side winding P2 is connected to the node R1;

[0006] The same-name terminal of the first low-side winding T1 is connected to the node L2, the different-name terminal of the first low-side winding T1 is connected to the same-name terminal of the second low-side winding T2, and the different-name terminal of the second low-side winding T2 is connected to the node R2; an output terminal Vo is connected to the connection line between the first low-side winding T1 and the second low-side winding T2;

[0007] The input capacitor Cin is placed between the input terminal Vin and the ground terminal GND or between the input terminal Vin and the output terminal Vo; the output capacitor Co is placed between the output terminal Vo and the ground terminal GND.

[0008] As a preferred solution, the resonant capacitor bank Cr includes a first resonant capacitor 51 and a second resonant capacitor 62 connected in parallel.

[0009] The technical problem to be solved by the present invention is: to provide a power supply module based on the above power conversion circuit.

[0010] To solve the above technical problem, the technical solution adopted by the present invention is: a power supply module based on the above power conversion circuit, including a printed circuit board PCB and a planar transformer, and the planar transformer includes a magnetic core and a magnetic component; the magnetic core includes a first magnetic substrate, a second magnetic substrate, a first side magnetic column, an intermediate magnetic column, and a second side magnetic column arranged in parallel, and the first side magnetic column, the intermediate magnetic column, and the second side magnetic column are arranged between the first magnetic substrate and the second magnetic substrate; the channels between the intermediate magnetic column, the first side magnetic column, and the second side magnetic column are winding channels; on the printed circuit board PCB, the two sides outside the first side magnetic column and the second side magnetic column are bridging channels;

[0011] The magnetic component includes four windings, namely the first high-side winding P1, the second high-side winding P2, the first low-side winding T1, and the second low-side winding T2, and the four windings are wound around the intermediate magnetic column through the winding channels.

[0012] The printed circuit board PCB is provided with an intermediate magnetic core hole matching the intermediate magnetic column, a first magnetic core hole matching the first magnetic substrate, and a second magnetic core hole matching the second magnetic substrate.

[0013] On one side of the transformer on the top surface of the printed circuit board (PCB), there are provided the first main control switch S1, the second main control switch S2, the third main control switch S3, the fourth main control switch S4 and the first resonant capacitor. This side is denoted as the input side of the power module; on the other side of the transformer on the top surface of the printed circuit board (PCB), there are provided the first synchronous rectification switch Q1, the second synchronous rectification switch Q2 and the output capacitor Co. This side is denoted as the output side of the power module;

[0014] The input capacitor Cin, the second resonant capacitor, the first drive chip and the second drive chip are placed at the input side of the power module on the bottom surface of the printed circuit board (PCB). The second resonant capacitor is placed at the back of the first resonant capacitor and is connected in parallel with it; the first synchronous rectification switch Q1, the second synchronous rectification switch Q2, the output capacitor Co, the third drive chip and the fourth drive chip are placed on the output side of the power module on the bottom surface of the printed circuit board (PCB);

[0015] The same-name end of the first high-side winding P1 is connected to the node L1 through a via, then wound around the winding channel and then connected to one end of the resonant capacitor bank Cr through a via; the other end of the resonant capacitor bank Cr is connected to the same-name end of the second high-side winding P2 through a via, then wound around the winding channel and then connected to the node R1 through a via; the node L1 is connected to the source of the first main control switch S1 through a via, and the node R1 is connected to the source of the second main control switch S2 through a via.

[0016] As a preferred solution, the same-name end of the first low-side winding T1 is connected to the node L2 through a via, then wound around the winding channel and then connected to the output terminal Vo through a via; the opposite-name end of the second low-side winding T2 is connected to the node R2 through a via, then wound around the winding channel and then connected to the output terminal Vo through a via; the node L2 is connected to the drain of the first synchronous rectification switch Q1 through a via, and the node R2 is connected to the drain of the second synchronous rectification switch Q2 through a via;

[0017] The second main control switch S2 and the first synchronous rectification switch Q1 are connected through the first bridging channel; the third main control switch S3 and the second synchronous rectification switch Q2 are connected through the second bridging channel; the first main control switch S1 and the second main control switch S2 are connected through the PCB circuit; the third main control switch S3 and the fourth main control switch S4 are connected through the PCB circuit; the first main control switch S1 and the second main control switch S2 are connected to the input terminal Vin through the PCB circuit.

[0018] As a preferred solution, when the input capacitor Cin is placed between the input terminal Vin and the output terminal Vo, the output terminal Vo is connected to the input capacitor Cin through the third bridging channel and the fourth bridging channel.

[0019] As a preferred solution, the first resonant capacitor is placed on the top surface of the printed circuit board, and the second resonant capacitor is placed on the bottom surface of the printed circuit board. The first resonant capacitor and the second resonant capacitor are symmetrically arranged and are connected in parallel through the first via and the second via; the first via is connected to the first high-side winding P1, and the second via is connected to the second high-side winding P2.

[0020] As a preferred solution, for a power supply module providing a fixed voltage transformation ratio of 4:1, the number of turns of both the first high-side winding P1 and the second high-side winding P2 is 1 turn; the number of turns of both the first low-side winding T1 and the second low-side winding T2 is 1 turn.

[0021] As a preferred solution, both the first high-side winding P1 and the second high-side winding P2 are multi-layer PCB windings connected in parallel; and the first high-side winding P1 and the second high-side winding P2 are arranged in an interleaved manner.

[0022] Another technical problem to be solved by the present invention is to provide a control method for a power supply module based on a power conversion circuit.

[0023] To solve the above technical problem, the technical solution adopted by the present invention is: a control method for a power supply module based on a power conversion circuit as described above, the first main control switch S1, the third main control switch S3, and the first synchronous rectifier switch Q1 are controlled to turn on and off by signal 1, and the second main control switch S2, the fourth main control switch S4, and the second synchronous rectifier switch Q2 are controlled to turn on and off by signal 2; signal 1 and signal 2 are complementary and conduct, with a duty cycle of 50%, and a dead zone is reserved between signal 1 and signal 2; the leakage inductance of the planar transformer resonates with the resonant capacitor bank Cr.

[0024] As a preferred solution, the switching frequencies of signal 1 and signal 2 are 0.9 - 1.1 times the resonant frequency.

[0025] Another technical problem to be solved by the present invention is to provide a startup method for a power supply module based on a power conversion circuit.

[0026] To solve the above technical problems, the technical solution adopted by the present invention is as follows: For the starting method of the power supply module based on the power conversion circuit, the first main control switch S1 and the third main control switch S3 are controlled to turn on and off by signal 3, and the second main control switch S2 and the fourth main control switch S4 are controlled to turn on and off by signal 4; the first synchronous rectification switch Q1 is controlled to turn on and off by signal 5, and the second synchronous rectification switch Q2 is controlled to turn on and off by signal 6; signal 3 and signal 4 conduct complementarily, and signal 5 and signal 6 conduct complementarily; signal 3 and signal 5 are in the same phase, and signal 4 and signal 6 are in the same phase; during startup, the duty cycles of signal 3 and signal 4 gradually increase from 0 to 50%, and the duty cycles of signal 5 and signal 6 gradually increase from 0 to 50%.

[0027] As a preferred solution, the expansion time of signal 5 and signal 6 is 0.9 times that of signal 3 and signal 4.

[0028] The beneficial effects of the present invention are as follows:

[0029] The power conversion circuit of the present invention decomposes the high-side winding of the planar transformer into two series-connected coils, and the resonant capacitor group is placed between the two coils; specifically, the first high-side winding P1 and the second high-side winding P2 are wound symmetrically about the center axis of the module, the resonant capacitor group Cr is placed in the exact middle of the module, and the terminals of the resonant capacitor group Cr are connected to the high-side winding through vias. This design can make the current path completely symmetrical in the positive and negative half-cycles of the circuit operation, and the windings on both sides of the resonant capacitor group Cr achieve impedance matching, thereby greatly reducing the winding loss and leakage inductance of the transformer.

[0030] The present invention places the input capacitor Cin of the power supply module between the input terminal Vin and the output terminal Vo, which can reduce the transmission path length of the high-side high-frequency resonant current by more than 20%, thereby significantly reducing the PCB line loss of the printed circuit board; in addition, this design can reduce the ripple current of the output capacitor by more than 25%, thereby significantly reducing the output capacitor loss.

[0031] The planar transformer structure and winding arrangement of the power supply module proposed by the present invention can wind the high-side winding and the low-side winding on the middle magnetic column, and the magnetomotive forces of the high-side winding current and the low-side winding current can be cancelled out, thereby reducing the winding loss caused by the proximity effect; the transformer winding is wrapped by the magnetic core, which can reduce the leakage inductance of the transformer.

[0032] The proposed layout of the high-density power module places four main control switch components S1, S2, S3, S4, the input capacitor Cin, and the resonant capacitor bank Cr on one side of the planar transformer, which is the input side of the power module; two synchronous rectifier switch components Q1, Q2, and the output capacitor Co are placed on the other side of the planar transformer, which is the output side of the power module; the input side and the output side are separated by the planar transformer. This layout can minimize the transmission distance of large-current circuits and reduce the line loss of the printed circuit board (PCB); this layout can place most of the switch components on the surface of the module, and the surface devices can directly contact the top radiator, greatly improving the heat dissipation performance of the module.

[0033] The proposed startup method of the power module realizes the slow establishment of the output voltage by controlling the duty cycle expansion timing of the main control switch components and the synchronous rectifier switch components. This method relies on software configuration and does not require any additional hardware, thus reducing the hardware complexity and cost of the power module. Description of the Drawings

[0034] Figure 1 It is for the first embodiment of the power conversion circuit of the power module;

[0035] Figure 2 It is for the second embodiment of the power conversion circuit of the power module;

[0036] Figure 3 It is a schematic diagram of the power module using a planar transformer;

[0037] Figure 4 It is a schematic diagram of the magnetic core;

[0038] Figure 5 It is a schematic diagram of the top layer layout of the power module;

[0039] Figure 6 It is a schematic diagram of the bottom layer layout of the power module;

[0040] Figure 7 It is a schematic diagram of the high-side winding connection;

[0041] Figure 8 Figure 9 It is a schematic diagram of the low-side winding connection;

[0042] Figure 10 It is a schematic diagram of the switch component connection;

[0043] Figure 11 It is a schematic diagram of the output terminal connection of the second circuit embodiment;

[0044] Figure 12 It is a schematic diagram of the connection between the resonant capacitor bank and the high-side winding

[0045] Figure 13 It is a circuit control timing diagram. Detailed Implementation Manner

[0046] The following will describe in detail the specific implementation of the present invention in conjunction with the accompanying drawings.

[0047] As Figure 1 shown, a power conversion circuit includes an input terminal Vin and a ground terminal GND, a proximal power conversion unit and a distal power conversion unit connected in parallel between the input terminal Vin and the ground terminal GND; the proximal power conversion unit includes a first main control switch S1, a second main control switch S2 and a first synchronous rectification switch Q1 connected in series; the distal power conversion unit includes a fourth main control switch S4, a third main control switch S3 and a second synchronous rectification switch Q2 connected in series; the connection node of the first main control switch S1 and the second main control switch S2 is denoted as L1, and the connection node of the second main control switch S2 and the first synchronous rectification switch Q1 is denoted as L2; the connection node of the fourth main control switch S4 and the third main control switch S3 is denoted as R1, and the connection node of the third main control switch S3 and the second synchronous rectification switch Q2 is denoted as R2;

[0048] The same - name end of the first high - side winding P1 is connected to the node L1, and the different - name end of the first high - side winding P1 is connected to one end of the resonant capacitor bank Cr; the other end of the resonant capacitor bank Cr is connected to the same - name end of the second high - side winding P2, and the different - name end of the second high - side winding P2 is connected to the node R1;

[0049] The same - name end of the first low - side winding T1 is connected to the node L2, the different - name end of the first low - side winding T1 is connected to the same - name end of the second low - side winding T2, and the different - name end of the second low - side winding T2 is connected to the node R2; an output terminal Vo is connected to the line between the first low - side winding T1 and the second low - side winding T2;

[0050] An input capacitor Cin is disposed between the input terminal Vin and the ground terminal GND; an output capacitor Co is disposed between the output terminal Vo and the ground terminal GND.

[0051] The resonant capacitor bank Cr includes a first resonant capacitor 51 and a second resonant capacitor 62 connected in parallel.

[0052] As Figure 2 shown, another power conversion circuit is different from the above - mentioned power conversion circuit in that the input capacitor Cin is disposed between the input terminal Vin and the output terminal Vo.

[0053] As Figures 3 - 12As shown in the figure, a power module includes a printed circuit board (PCB) 11 and a planar transformer. The planar transformer includes a magnetic core 12 and a magnetic component. The magnetic core includes a first magnetic substrate 21 and a second magnetic substrate 22 arranged in parallel, and a first side magnetic post 23, an intermediate magnetic post 24, and a second side magnetic post 25. The first side magnetic post 23, the intermediate magnetic post 24, and the second side magnetic post 25 are arranged between the first magnetic substrate 21 and the second magnetic substrate 22. The channels between the intermediate magnetic post 24, the first side magnetic post 23, and the second side magnetic post 25 are winding channels. On the printed circuit board PCB11, the two sides outside the first side magnetic post 23 and the second side magnetic post 25 are bridging channels.

[0054] The magnetic component includes four windings, namely the first high-side winding P1, the second high-side winding P2, the first low-side winding T1, and the second low-side winding T2. The four windings are wound around the intermediate magnetic post 23 through the winding channels.

[0055] On the printed circuit board PCB11, there are an intermediate magnetic core hole that cooperates with the intermediate magnetic post 24, a first magnetic core hole 54 that cooperates with the first magnetic substrate 21, and a second magnetic core hole 55 that cooperates with the second magnetic substrate 22.

[0056] The first main control switch S1, the second main control switch S2, the third main control switch S3, the fourth main control switch S4, and the first resonant capacitor 51 are placed on one side of the transformer on the top surface of the printed circuit board PCB11. This side is denoted as the input side of the power module. The first synchronous rectification switch Q1, the second synchronous rectification switch Q2, and the output capacitor Co52 are placed on the other side of the transformer on the top surface of the printed circuit board PCB11. This side is denoted as the output side of the power module. The first synchronous rectification switch Q1 includes a number of first rectification switch units Q1' connected in parallel, and the second synchronous rectification switch Q2 includes a number of second rectification switch units Q2' connected in parallel.

[0057] As Figure 6 shown, the input capacitor Cin61, the second resonant capacitor 62, the first drive chip 64, and the second drive chip 65 are placed on the input side of the power module on the bottom surface of the printed circuit board PCB11. The second resonant capacitor 62 is placed on the back of the first resonant capacitor 51 and is connected in parallel with it. The first synchronous rectification switch Q1, the second synchronous rectification switch Q2, the output capacitor Co63, and the third drive chip 66 and the fourth drive chip 67 are placed on the output side of the power module on the bottom surface of the printed circuit board PCB11.

[0058] As Figure 7As shown, the same-name end of the first high-side winding P1 71 is connected to the node L1 through a via, then wound around the winding channel and connected to one end of the resonant capacitor bank Cr62 through a via; the other end of the resonant capacitor bank Cr62 is connected to the same-name end of the second high-side winding P2 72 through a via, then wound around the winding channel and connected to the node R1 through a via; the node L1 is connected to the source of the first main control switch S1 through a via, and the node R1 is connected to the source of the second main control switch S2 through a via.

[0059] As Figure 8 shown, the same-name end of the first low-side winding T1 81 is connected to the node L2 through a via, then wound around the winding channel and connected to the output terminal Vo through a via; As Figure 9 shown, the opposite-name end of the second low-side winding T2 91 is connected to the node R2 through a via, then wound around the winding channel and connected to the output terminal Vo through a via; the node L2 is connected to the drain of the first synchronous rectification switch Q1 through a via, and the node R2 is connected to the drain of the second synchronous rectification switch Q2 through a via;

[0060] For a power module providing a fixed voltage transformation ratio of 4:1, the number of turns of both the first high-side winding P1 and the second high-side winding P2 is 1 turn. The number of turns of both the first low-side winding T1 and the second low-side winding T2 is 1 turn.

[0061] As Figure 10 shown, the second main control switch S2 and the first synchronous rectification switch Q1 are connected through the first bridging channel 114; the third main control switch S3 and the second synchronous rectification switch Q2 are connected through the second bridging channel 115; the first main control switch S1 and the second main control switch S2 are connected through the PCB line 112, and the third main control switch S3 and the fourth main control switch S4 are connected through the PCB line 113; the first main control switch S1 and the second main control switch S2 are connected to the input terminal Vin through the PCB line 111;

[0062] When the input capacitor Cin is placed between the input terminal Vin and the output terminal Vo, the output terminal Vo is connected to the input capacitor Cin61 through the third bridging channel 101 and the fourth bridging channel 102, and the circuit schematic is as Figure 11 shown.

[0063] The connection manner of the first high-side winding P1, the second high-side winding P2 and the resonant capacitor bank Cr is as Figure 12 shown. The first resonant capacitor 51 is placed on the top surface 121 of the printed circuit board, the second resonant capacitor 62 is placed on the bottom surface 122 of the printed circuit board, the first resonant capacitor 51 and the second resonant capacitor 62 are symmetrically arranged, and are connected in parallel through the first via 123 and the second via 124;

[0064] The first viaduct 123 is connected to the first high-side winding P1, and the second viaduct 124 is connected to the second high-side winding P2. The first high-side winding P1 and the second high-side winding P2 are multi-layer PCB windings connected in parallel ( Figure 12 The schematic diagram shows two layers connected in parallel); the first high-side winding P1 and the second high-side winding P2 are arranged in a staggered manner.

[0065] This design can make the current path completely symmetrical in the positive and negative half-cycles of the circuit operation, and the two-side windings of the resonant capacitor bank achieve impedance matching, thereby greatly reducing the transformer winding loss and leakage inductance.

[0066] As Figure 13 shown, the control mode of the power supply module is that the first main control switch S1, the third main control switch S3, and the first synchronous rectifier switch Q1 are controlled to turn on and off by signal 1, and the second main control switch S2, the fourth main control switch S4, and the second synchronous rectifier switch Q2 are controlled to turn on and off by signal 2; signal 1 and signal 2 are complementary to each other in conduction, the duty cycle is 50%, and a dead zone is reserved between signal 1 and signal 2; the leakage inductance of the planar transformer resonates with the resonant capacitor bank Cr. The switching frequencies of signal 1 and signal 2 are 0.9 - 1.1 times the resonant frequency.

[0067] The starting mode of the power supply module is that the first main control switch S1 and the third main control switch S3 are controlled to turn on and off by signal 3, and the second main control switch S2 and the fourth main control switch S4 are controlled to turn on and off by signal 4; the first synchronous rectifier switch Q1 is controlled to turn on and off by signal 5, and the second synchronous rectifier switch Q2 is controlled to turn on and off by signal 6; signal 3 and signal 4 are complementary to each other in conduction, and signal 5 and signal 6 are complementary to each other in conduction; signal 3 and signal 5 are in the same phase, and signal 4 and signal 6 are in the same phase; during startup, the duty cycles of signal 3 and signal 4 increase gradually from 0 to 50%, and the duty cycles of signal 5 and signal 6 increase gradually from 0 to 50%. The expansion time of signal 5 and signal 6 is 0.9 times the expansion time of signal 3 and signal 4.

[0068] The above embodiments only illustrate the principles and effects of the present invention and some applied embodiments, rather than limiting the present invention; it should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A power conversion circuit, comprising an input terminal Vin and a ground terminal GND, a proximal power conversion unit and a distal power conversion unit connected in parallel between the input terminal Vin and the ground terminal GND; the proximal power conversion unit comprises a first main control switch S1, a second main control switch S2 and a first synchronous rectification switch Q1 connected in series; the distal power conversion unit comprises a fourth main control switch S4, a third main control switch S3 and a second synchronous rectification switch Q2 connected in series; a connection node between the first main control switch S1 and the second main control switch S2 is marked as L1, and a connection node between the second main switch S2 and the first synchronous rectification switch Q1 is marked as L2; ​​a connection node between the fourth main switch S4 and the third main switch S3 is marked as R1, and a connection node between the third main switch S3 and the second synchronous rectification switch Q2 is marked as R2; Features: The same-name end of the first high-side winding P1 is connected to the node L1, and the opposite-name end of the first high-side winding P1 is connected to one end of the resonant capacitor group Cr; the other end of the resonant capacitor group Cr is connected to the same-name end of the second high-side winding P2, and the opposite-name end of the second high-side winding P2 is connected to the node R1; The same-name end of the first low-side winding T1 is connected to the node L2, the opposite-name end of the first low-side winding T1 is connected to the same-name end of the second low-side winding T2, and the opposite-name end of the second low-side winding T2 is connected to the node R2; the line between the first low-side winding T1 and the second low-side winding T2 is connected to the output terminal Vo; The input capacitor Cin is placed between the input terminal Vin and the ground terminal GND or between the input terminal Vin and the output terminal Vo; the output capacitor Co is placed between the output terminal Vo and the ground terminal GND.

2. A power conversion circuit as claimed in claim 1, characterized in that: The resonant capacitor group Cr comprises a first resonant capacitor (51) and a second resonant capacitor (62) connected in parallel.

3. A power module based on the power conversion circuit according to claim 2, characterized in that: The invention comprises a printed circuit board (PCB) (11) and a planar transformer, wherein the planar transformer comprises a magnetic core (12) and a magnetic component; the magnetic core comprises a first magnetic substrate (21), a second magnetic substrate (22) and a first side magnetic column (23), a middle magnetic column (24) and a second side magnetic column (25) arranged in parallel; the first side magnetic column (23), the middle magnetic column (24) and the second side magnetic column (25) are arranged between the first magnetic substrate (21) and the second magnetic substrate (22); the channel between the middle magnetic column (24), the first side magnetic column (23) and the second side magnetic column (25) is a winding channel; and the two sides of the printed circuit board (PCB) (11) outside the first side magnetic column (23) and the second side magnetic column (25) are bridge channels; The magnetic component comprises four windings, namely the first high-side winding P1, the second high-side winding P2, the first low-side winding T1, and the second low-side winding T2, and the four windings are wound on the middle magnetic column (23) through a winding channel; A middle magnetic core hole matched with the middle magnetic column (24), a first magnetic core hole (54) matched with the first magnetic substrate (21), and a second magnetic core hole (55) matched with the second magnetic substrate (22) are provided on the printed circuit board PCB (11). The first main control switch component S1, the second main control switch component S2, the third main control switch component S3, the fourth main control switch component S4 and the first resonant capacitor (51) are arranged on one side of the transformer on the top surface of the printed circuit board PCB (11), and this side is marked as the input side of the power module; the first synchronous rectification switch component Q1, the second synchronous rectification switch component Q2 and the output capacitor Co (52) are arranged on the other side of the transformer on the top surface of the printed circuit board PCB (11), and this side is marked as the output side of the power module; The input capacitor Cin (61), the second resonant capacitor (62), the first driver chip (64), and the second driver chip (65) are placed on the input side of the power module on the bottom surface of the printed circuit board PCB (11); the second resonant capacitor (62) is placed on the back side of the first resonant capacitor (51) and is connected in parallel therewith; the first synchronous rectification switch element Q1, the second synchronous rectification switch element Q2, the output capacitor Co (63), and the third driver chip (66), and the fourth driver chip (67) are placed on the output side of the power module on the bottom surface of the printed circuit board PCB (11); The same-name end of the first high-side winding P1 (71) is connected to the node L1 through a via hole, and then is wound on the winding channel and connected to one end of the resonant capacitor group Cr (62) through a via hole; the other end of the resonant capacitor group Cr (62) is connected to the same-name end of the second high-side winding P2 (72) through a via hole, and then is wound on the winding channel and connected to the node R1 through a via hole; the node L1 is connected to the source of the first main control switch component S1 through a via hole, and the node R1 is connected to the source of the second main control switch component S2 through a via hole.

4. The power module based on the power conversion circuit according to claim 3, characterized in that: The same-name end of the first low-side winding T1 (81) is connected to the node L2 through a via hole, and then is wound in a winding channel and connected to the output terminal Vo through a via hole; the opposite-name end of the second low-side winding T2 (91) is connected to the node R2 through a via hole, and then is wound in a winding channel and connected to the output terminal Vo through a via hole; the node L2 is connected to the drain of the first synchronous rectification switch device Q1 through a via hole, and the node R2 is connected to the drain of the second synchronous rectification switch device Q2 through a via hole; The second main control switch component S2 is connected to the first synchronous rectification switch component Q1 via a first bridge channel (114); the third main control switch component S3 is connected to the second synchronous rectification switch component Q2 via a second bridge channel (115); the first main control switch component S1 is connected to the second main control switch component S2 via a PCB circuit (112), and the third main control switch component S3 is connected to the fourth main control switch component S4 via a PCB circuit (113); the first main control switch component S1 and the second main control switch component S2 are connected to an input terminal Vin via a PCB circuit (111).

5. The power module based on the power conversion circuit according to claim 4, characterized in that: When the input capacitor Cin is placed between the input terminal Vin and the output terminal Vo, the output terminal Vo is connected to the input capacitor Cin61 through the third bridge channel (101) and the fourth bridge channel (102).

6. The power module based on the power conversion circuit according to claim 5, characterized in that: The first resonant capacitor (51) is placed on the top surface (121) of the printed circuit board, and the second resonant capacitor (62) is placed on the bottom surface (122) of the printed circuit board; the first resonant capacitor (51) and the second resonant capacitor (62) are symmetrically arranged and connected in parallel via a first via hole (123) and a second via hole (124); the first via hole (123) is connected to the first high-side winding P1, and the second via hole (124) is connected to the second high-side winding P2.

7. The power module based on the power conversion circuit according to claim 6, characterized in that: For a power module providing a fixed voltage transformation ratio of 4:1, the number of turns of the first high-side winding P1 and the second high-side winding P2 are both 1 turn; the number of turns of the first low-side winding T1 and the second low-side winding T2 are both 1 turn.

8. The power module based on the power conversion circuit according to claim 5, characterized in that: The first high-side winding P1 and the second high-side winding P2 are both multi-layer PCB windings connected in parallel; and the first high-side winding P1 and the second high-side winding P2 are arranged in an alternating manner.

9. A control method for a power module based on a power conversion circuit as described in any one of claims 3-8, wherein the first main control switch element S1, the third main control switch element S3, and the first synchronous rectification switch element Q1 are controlled by signal 1 to be turned on and off, and the second main control switch element S2, the fourth main control switch element S4, and the second synchronous rectification switch element Q2 are controlled by signal 2 to be turned on and off; signal 1 and signal 2 are complementary to each other, with a duty cycle of 50%, and a dead zone is reserved between signal 1 and signal 2; the leakage inductance of the planar transformer resonates with the resonant capacitor group Cr.

10. A control method for a power module based on a power conversion circuit according to claim 9, wherein the switching frequency of the signal 1 and the signal 2 is 0.9-1.1 times the resonant frequency.

11. A method for starting a power module based on a power conversion circuit as described in any one of claims 3 to 8, wherein the first main control switch element S1 and the third main control switch element S3 are controlled by signal 3 to turn on and off, and the second main control switch element S2 and the fourth main control switch element S4 are controlled by signal 4 to turn on and off; the first synchronous rectification switch element Q1 is controlled by signal 5 to turn on and off, and the second synchronous rectification switch element Q2 is controlled by signal 6 to turn on and off; signal 3 and signal 4 are complementary to each other, and signal 5 and signal 6 are complementary to each other; signal 3 and signal 5 are in the same phase, and signal 4 and signal 6 are in the same phase; during startup, the duty ratio of signal 3 and signal 4 gradually increases from 0 to 50%, and the duty ratio of signal 5 and signal 6 gradually increases from 0 to 50%.

12. A method for starting a power module based on a power conversion circuit according to any one of claims 3 to 8, wherein the development time of signal 5 and signal 6 is 0.9 times the development time of signal 3 and signal 4.

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