Power conversion device

Abstract

The invention discloses a power conversion device which comprises a transformer assembly, a switching tube, an output capacitor and a driving unit, and the conversion efficiency of the power conversion device is optimized. On the other hand, the invention discloses the layout of the power conversion device, including the layout of the transformer region, the switch region, the output capacitor region and the port region, and through reasonable layout, the conversion efficiency of the power conversion device is further improved; and on the other hand, a current sampling scheme suitable for the power conversion device is disclosed, and comprehensive detection and monitoring of the current of the power conversion device and a current sharing function when a plurality of power conversion devices are connected in parallel are realized through time division multiplexing of a control pin.

Description

Technical Field

[0001] The invention belongs to the technical field of high-frequency power supply, and in particular relates to a power conversion device. Background Art

[0002] With the development of artificial intelligence, the power requirements of artificial intelligence data processing chips, such as CPU, GPU, TPU, etc. (collectively referred to as xPU) are getting higher and higher, which has greatly increased the power of servers and increased the power supply voltage of server system boards from 12V to 48V. In applications where the power supply voltage of server system boards is 48V, the two-stage step-down circuit architecture has gradually become the mainstream.

[0003] The intermediate bus conversion device in the two-stage step-down circuit architecture is a conversion device used to realize voltage conversion between the input bus and the output bus, including two types of ratios of input voltage to output voltage, fixed gain ratio or non-fixed gain ratio. The intermediate bus conversion device with a fixed gain ratio steps down the input voltage of the server motherboard in the range of 40 to 60V to the output voltage at a ratio of 4:1, 8:1 or 12:1, and supplies the voltage regulator load for the artificial intelligence chip. As the power consumption on the server motherboard increases, the power that needs to be provided by the intermediate bus conversion device with a fixed gain ratio is also increasing, and the requirements for power density and conversion efficiency are getting higher and higher.

[0004] The present invention proposes a solution for a power conversion device with a fixed gain ratio output having high power density and high conversion efficiency, including a driving circuit of a power switch and a layout of a power device. Summary of the invention

[0005] In view of this, one of the objects of the present invention is to provide a power conversion device, which improves the conversion efficiency by optimizing the layout of power devices in the power conversion device; by improving the driving circuit, the soft switching function of the switch tube in the power conversion circuit is guaranteed, and the turn-off loss of the switch tube is further reduced; by adding a current sampling function to the pre-charging unit, the current comprehensive detection and overcurrent protection during the operation of the power conversion device are realized, and by time-sharing a pin of a controller or a microprocessor with the address function of the power management bus, under the condition of limited number of pins, the current sharing or current reporting function when multiple power conversion devices are used in parallel is realized.

[0006] In one aspect, the present invention provides a power conversion device, including a circuit substrate, a transformer assembly, a switch tube, an output capacitor, an input positive terminal, an output positive terminal, and an output negative terminal;

[0007] The circuit substrate comprises a first surface and a second surface opposite to each other, the first surface comprising a transformer area, a switch area, an output capacitor area and a port area;

[0008] The transformer assembly is arranged in the transformer area, the switch tube is arranged in the switch area, at least a part of the output capacitor is arranged in the output capacitor area, and the input positive terminal, the output positive terminal and the output negative terminal are arranged in the port area;

[0009] The transformer area, switch area, output capacitor area and port area are arranged in the same direction.

[0010] Preferably, the output positive terminal includes at least two output positive terminal gold fingers, the output negative terminal includes at least two output negative terminal gold fingers, and the output positive terminal gold fingers and the output negative terminal gold fingers are alternately arranged in the port area.

[0011] Preferably, the power conversion device further comprises a signal terminal, the signal terminal comprises at least two signal terminal gold fingers, and the signal terminal gold fingers are arranged on one side of the port area.

[0012] Preferably, the switch tube includes two middle switches and two lower switches, the two lower switches are arranged between the two middle switches, and the middle switch and the lower switch are arranged adjacent to the transformer area.

[0013] Preferably, the switch tube further includes two upper switches, and the two upper switches are respectively arranged adjacent to one of the middle switches.

[0014] Preferably, the power conversion device further comprises a lower switch driving area and two middle and upper switch driving areas, wherein the two middle and upper switch driving areas are respectively arranged on opposite sides of the switch area and are arranged adjacent to the middle switch and / or the lower switch.

[0015] Preferably, the power conversion device also includes a driving unit, which includes a driving magnetic component, a lower switch driving unit, a middle switch driving unit and an upper switch driving unit, the driving magnetic component and the lower switch driving unit are arranged in the lower switch driving area, and the middle switch driving unit and the upper switch driving unit are arranged in the middle-upper switch driving area.

[0016] Preferably, the second surface includes a signal area and a port area, and the output positive gold finger and the output negative gold finger are alternately arranged in the port area of ​​the second surface; the projection of at least one output positive gold finger arranged on the second surface on the first surface at least partially overlaps with at least one corresponding output positive gold finger arranged on the first surface; the projection of at least one output negative gold finger arranged on the second surface on the first surface at least partially overlaps with at least one corresponding output negative gold finger arranged on the first surface.

[0017] Preferably, the second surface includes a switch area, and the switch tube also includes two other middle switches and two other lower switches, and the other two middle switches and the other two lower switches are arranged in the switch area of ​​the second surface, and the projection of at least one middle switch or the lower switch arranged in the switch area of ​​the second surface on the first surface at least partially overlaps with the projection of the corresponding middle switch or the corresponding lower switch arranged on the first surface on the first surface.

[0018] Preferably, the second surface includes an output capacitor area, at least a portion of the output capacitor is arranged in the output capacitor area of ​​the second surface, and the output capacitor arranged on the second surface is partially or entirely projected on the first surface within the output capacitor area of ​​the first surface.

[0019] Preferably, the first surface and / or the second surface comprises a resonant capacitor region, and the resonant capacitor region is arranged adjacent to one of the middle switches or one of the upper switches.

[0020] Another aspect of the present invention provides a power conversion device, including a power conversion circuit, a drive unit and a control signal;

[0021] The power conversion circuit comprises an input positive terminal, an input negative terminal, an output positive terminal and an output negative terminal, wherein the input negative terminal and the output negative terminal are short-circuited; the power conversion circuit comprises a three-switch bridge arm, wherein the three-switch bridge arm comprises a first upper switch, a first middle switch and a first lower switch electrically connected in series, wherein the first upper switch is electrically connected to the input positive terminal, wherein the first upper switch and the first middle switch are electrically connected to a first upper node, and wherein the first middle switch and the first lower switch are electrically connected to a first lower node; the power conversion circuit further comprises a second lower switch, wherein the first lower switch and the second lower switch are electrically connected to the input negative terminal;

[0022] The control signal includes a first control signal, a second control signal, a third control signal and a fourth control signal;

[0023] The driving unit includes a driving magnetic part, a lower switch driving unit, a middle switch driving unit and a lower switch driving unit, the lower switch driving unit receives a first control signal, a second control signal, a third control signal and a fourth control signal, the lower switch driving unit outputs a lower switch driving signal to drive the two lower switches to be turned on and off, and the lower switch driving unit is electrically connected to the driving magnetic part; the middle switch driving unit receives the control signal through the driving magnetic part, and the middle switch driving unit outputs a middle switch driving signal to drive the two middle switches to be turned on and off; the upper switch driving unit receives the control signal through the driving magnetic part, and the upper switch driving unit outputs an upper switch driving signal to drive the two upper switches to be turned on and off.

[0024] Preferably, the lower switch driving unit includes a positive terminal of a driving power supply, a ground terminal, a first lower switch driving output terminal and a second lower switch driving output terminal, and the lower switch driving unit also includes four control switches, the four control switches are electrically connected to form a full-bridge structure and are bridged between the positive terminal of the driving power supply and the ground terminal, the first lower switch driving output terminal and the second lower switch driving output terminal are respectively the midpoints of the two bridge arms; the four control switches are respectively controlled by a first control signal, a second control signal, a third control signal and a fourth control signal.

[0025] Preferably, the driving magnetic component includes a driving winding, a first middle winding and a first upper winding, and the driving winding, the first middle winding and the first upper winding are wound on the same magnetic core; the driving winding is bridged between the first lower switch driving output terminal and the second lower switch driving output terminal.

[0026] Preferably, the middle switch driving unit includes two middle driving switches, the drains of the two middle driving switches are respectively electrically connected to the two ends of the first middle winding, and the sources of the two middle driving switches are short-circuited to the first lower node; one end of the first middle winding and the first lower node constitute the first middle switch driving output end; the voltage between any end of the first middle winding and the first lower node is used to control the middle driving switch electrically connected to the other end of the first middle winding.

[0027] Preferably, the upper switch driving unit includes two upper driving switches, the drains of the two upper driving switches are respectively electrically connected to the two ends of the first upper winding, and the sources of the two upper driving switches are short-circuited to the first upper node; one end of the first upper winding and the first upper node constitute the first upper switch driving output end; the voltage between any end of the first upper winding and the first upper node is used to control the upper driving switch electrically connected to the other end of the first upper winding.

[0028] Another aspect of the present invention provides a power conversion device, including a power conversion circuit, a pre-charging unit, a sampling resistor and a sampling circuit unit;

[0029] The power conversion circuit comprises an input positive terminal, an input negative terminal, an output positive terminal, an output negative terminal and an output capacitor, wherein the input negative terminal and the output negative terminal are short-circuited, and the output capacitor is connected across the output positive terminal and the output negative terminal;

[0030] The sampling circuit unit is used to sample the working current of the power conversion circuit;

[0031] The pre-charging unit comprises a switch end, an inductor end and a ground end, the switch end is electrically connected to the input positive end, the inductor end is electrically connected to the output positive end through the sampling resistor, and the ground end is electrically connected to the input negative end; the pre-charging unit pre-charges the output capacitor;

[0032] The sampling resistor is used to sample the outflow current of the pre-charging unit.

[0033] Preferably, the power conversion circuit also includes two lower switches and two low-voltage windings; the first ends of the two low-voltage windings are electrically connected to the output positive end, and the second end of each of the low-voltage windings is electrically connected to one end of a lower switch respectively to form two lower nodes; the other end of the lower switch is electrically connected to the output negative end.

[0034] Preferably, the sampling circuit unit includes three sampling terminals, a reference terminal, a sampling output positive terminal and a sampling output negative terminal, two of the three sampling terminals are electrically connected to a corresponding lower node respectively, another of the three sampling terminals is electrically connected to the output positive terminal, and the reference terminal is electrically connected to the output positive terminal.

[0035] Preferably, the sampling circuit unit further includes three sampling resistors, a sampling capacitor, an impedance matching resistor and an amplifying unit; the first ends of the three sampling resistors are electrically connected to the midpoint of the sampling resistors, and the second end of each of the sampling resistors is electrically connected to a sampling end respectively; the sampling capacitor and the impedance matching resistor are electrically connected in series between the reference end and the midpoint of the sampling resistor; the amplifying unit includes two input ends and two output ends, the two input ends are electrically connected to the two ends of the sampling capacitor respectively, and the two output ends are electrically connected to the sampling output positive end and the sampling output negative end respectively.

[0036] Preferably, the pre-charging unit also includes two pre-charging switches, a pre-charging inductor, a pre-charging capacitor and a pre-charging diode; the two pre-charging switches are electrically connected in series between the switch end and the ground end; one end of the pre-charging inductor is electrically connected to the series connection point of the two pre-charging switches, and the other end is electrically connected to the positive electrode of the pre-charging diode and the positive end of the output capacitor; the negative electrode of the pre-charging diode is electrically connected to the inductor end; and the negative end of the output capacitor is electrically connected to the ground end.

[0037] Preferably, when the terminal voltage across the output capacitor reaches a predetermined voltage, the pre-charging unit stops working; the predetermined voltage is greater than 70% of the output steady-state voltage Vo_normal of the power conversion circuit.

[0038] Another aspect of the present invention provides a power conversion device, including a power conversion circuit, a controller, a gating circuit, a current equalizing circuit unit, an address circuit unit, and a start control signal;

[0039] The gating circuit includes two input terminals, a control terminal and an output terminal, the two input terminals are electrically connected to the current balancing circuit unit and the address circuit unit respectively, the output terminal is electrically connected to the controller, and the control terminal receives the start control signal;

[0040] The controller is used to control the power conversion circuit;

[0041] The start control signal controls the gating circuit, and the voltage of the current balancing circuit unit or the voltage of the address circuit unit is sent to the controller through the gating circuit.

[0042] Preferably, the power conversion device further comprises a current source;

[0043] When the start control signal is at a low level, the current source charges the address circuit unit, and the voltage of the address circuit unit is sent to the controller through the gating circuit;

[0044] When the start control signal is at a high level, the current source charges the current balancing circuit unit, and the voltage of the current balancing circuit unit is sent to the controller through the gating circuit.

[0045] Preferably, the power conversion device includes a ground terminal; the current balancing circuit unit includes a current balancing resistor, a current balancing capacitor and a current balancing switch; the current balancing resistor and the current balancing capacitor are electrically connected in parallel between an input terminal of the selection circuit and the current balancing switch, one end of the current balancing switch is electrically connected to the ground terminal, and the other end of the current balancing switch is electrically connected to the current balancing resistor and the current balancing capacitor; the current balancing switch is controlled by the start control signal.

[0046] Preferably, the power conversion device includes a ground terminal; the address circuit unit includes an address resistor and an address capacitor, and the address resistor and the address capacitor are electrically connected in parallel between an input terminal of the selection circuit and the ground terminal.

[0047] Another aspect of the present invention provides a power conversion device, including a power conversion circuit, a dummy load unit, a power supply voltage and a dummy load control signal;

[0048] The power conversion circuit comprises an input positive terminal, an input negative terminal, an output positive terminal and an output negative terminal, wherein the input negative terminal and the output negative terminal are short-circuited;

[0049] The power conversion circuit further includes an input capacitor and an output capacitor, wherein the input capacitor is connected between the input positive terminal and the output positive terminal, and the output capacitor is connected between the output positive terminal and the output negative terminal;

[0050] One end of the dummy load unit is electrically connected to the supply voltage, and the other end is electrically connected to the output positive terminal;

[0051] The dummy load control signal controls the dummy load unit to discharge the output positive terminal.

[0052] Preferably, when the dummy load control signal is at a low level, the dummy load unit is switched into the power conversion device; when the dummy load control signal is at a high level, the dummy load unit is switched out of the power conversion device.

[0053] Preferably, the power conversion device also includes a starting control signal and a preset voltage; when the starting control signal of the power conversion device is at a high level, the dummy load control signal is at a high level; when the starting control signal of the power conversion device is at a low level, and the output voltage of the power conversion device is greater than or equal to the preset voltage, the dummy load control signal is at a high level; when the starting control signal of the power conversion device is at a low level, and the output voltage of the power conversion device is less than the preset voltage, the dummy load control signal is at a low level.

[0054] Preferably, the dummy load unit includes a power supply end, a ground end, a first dummy load control switch, a second dummy load control switch, a dummy load amplifying switch, a first current limiting resistor, a second current limiting resistor, a third current limiting resistor and a fourth current limiting resistor; the first current limiting resistor and the first dummy load control switch are connected in series between the power supply end and the ground end, and the gate of the first dummy load control switch is electrically connected to the dummy load control signal; the second current limiting resistor, the second dummy load control switch and the third current limiting resistor are connected in series between the power supply end and the ground end, and the gate of the second dummy load control switch is electrically connected to the drain of the first dummy load control switch; the dummy load amplifying switch and the fourth current limiting resistor are connected in series between the output positive end and the ground end of the power conversion device, and the base of the dummy load amplifying switch is electrically connected to the source of the second dummy load control switch.

[0055] Preferably, the dummy load unit includes a dummy load amplifying switch and a current limiting resistor, the dummy load amplifying switch is electrically connected to the output positive terminal of the power conversion device; the dummy load control signal is used to control the opening and closing of the dummy load amplifying switch; the current limiting resistor is used to control the current flowing through the dummy load amplifying switch.

[0056] The beneficial effects of the present invention are: improving conversion efficiency by optimizing the layout of power devices in a power conversion device; ensuring the soft switching function of the switch tube in the power conversion circuit by improving the driving circuit, and further reducing the turn-off loss of the switch tube; realizing comprehensive current detection and overcurrent protection during the operation of the power conversion device by adding a current sampling function to the pre-charging unit, and realizing current sharing or current reporting functions when multiple power conversion devices are used in parallel by time-sharing a pin of a controller or a microprocessor through the address function of the power management bus, under the condition of a limited number of pins. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0058] Figure 1 It is a topological diagram of a power conversion circuit;

[0059] Figure 2A and Figure 2B A circuit diagram of a power conversion device and a current sampling unit;

[0060] Figure 2C is a circuit diagram of another current sampling unit;

[0061] Figure 3A is a schematic diagram of a driving unit of a power conversion device;

[0062] FIG. 3B to FIG. 3D A control timing diagram used by a power conversion device;

[0063] Figure 4 A schematic diagram of a dummy load unit used in a power conversion device;

[0064] Figure 5 It is a schematic diagram of the time-division multiplexing function in the power conversion device;

[0065] FIG. 6A to FIG. 6D It is a schematic diagram of the layout of the power conversion device.

[0066] in:

[0067] 1 / 1a power conversion circuit; 10 circuit substrate; 11a first switch bridge arm; 11b second switch bridge arm; 2 / 2a pre-charging unit; 20 transformer core; 21 / 22 transformer magnetic substrate; 23 / 24 transformer side column; 25 transformer middle column; 3 / 3a / 3b current sampling unit; 31 / 32 amplification unit; 4 transformer assembly; 4a drive unit; 41 lower switch drive unit; 42 middle switch drive unit; 43 upper switch drive unit; 44 drive magnetic component; 50 circuit unit; 5a dummy load unit; 60 selection switch; 6a selection circuit; 70 slot; 71 / 75 hole; 72 / 73 / 74 slot; 80 drive core; 81 / 82 drive magnetic substrate; 83 / 84 drive side column; 101 first table surface; 102 second surface; 110 / 210 port area; 111 / 211 output capacitor area; 112 / 212 switch area; 113 / 213 transformer core area; 114 / 214 resonant capacitor area; 120 lower switch drive area; 121 / 122 / 221 / 222 middle and upper switch drive area; A1 / A2 upper node; ADDR0 address signal; B1 / B2 lower node; C1 sampling capacitor; C61 address capacitor; C62 current sharing capacitor; Cin input capacitor; Cc1 pre-charge capacitor; Co output capacitor; Cr resonant capacitor; Dc1 pre-charge diode; F sampling resistor midpoint; G / GND ground terminal; Ho1 / Ho2 upper switch drive output; in1 / in2 input terminal; IMON current sharing signal; I MON / ADDR0 pin; Lc1 pre-charge inductor; Llk equivalent resonant inductor; Lo1 / Lo2 lower switch drive output; Loadoff dummy load control signal; Mo1 / Mo2 middle switch drive output; out output terminal; PWM1 first control signal; PWM2 second control signal; PWM3 third control signal; PWM4 fourth control signal; Q1 / Q3 upper switch; Q2 / Q4 middle switch; Q11 / Q12 / Q13 / Q14 control switch; Qc1 / Qc2 pre-charge switch; Q21 / Q22 / Q23 / Q24 / Q25 / Q26 / Q27 / Q28 drive switch; Q51 / Q52 dummy load control switch; Q53 dummy load amplifier switch; Q61 address switch; Q62 Current sharing switch; Q63 ground switch; R1 / R2 / Rc sampling resistor; R20 second resistor; R30 third resistor; R40 fourth resistor; R50 fifth resistor; R51~R54 current limiting resistor; R6 impedance matching resistor; R61 address resistor; R62 current sharing resistor; S control terminal; S1 / S2 sampling terminal; signal terminal; SR1 / SR2 lower switch; t1~t8 time; Ts switching cycle; Vc power supply terminal; Vcc power supply voltage; Vcs sampling output voltage; Vcs1 current sampling signal; Vcs1+ sampling output positive terminal; Vcs1- sampling output negative terminal; Vdrv drive positive terminal; Vin+ input positive terminal; Vin- input negative terminal; V(Lo1-Lo2) drive winding voltage drop;Vo+ output positive terminal; Vo- output negative terminal; Vr1 reference terminal; W1 high voltage winding; W21 / W22 low voltage winding; W31 drive winding; W41 first middle winding; W42 second middle winding; W43 first upper winding; W44 second upper winding; xx axis; yy axis; OP op amp. ; DETAILED DESCRIPTION

[0068] One of the core aspects of the present invention is to provide a power conversion device including a transformer assembly, a switch tube, an output capacitor and a drive unit, and to optimize the conversion efficiency of the power conversion device by reducing the turn-off loss of the switch by optimizing the drive unit.

[0069] The present invention also provides a layout of power devices of a power conversion device, including the layout of a transformer area, a switch area, an output capacitor area and a port area. Through a reasonable layout, the conversion efficiency of the power conversion device is further improved.

[0070] The present invention also provides a current sampling scheme suitable for the power conversion device, which realizes comprehensive current detection and overcurrent protection during the operation of the power conversion device; and through a control pin of a time-sharing multiplexing controller or a microprocessor, not only the address function of the power management bus is realized, but also the current sharing or current reporting function when multiple power conversion devices are used in parallel is realized.

[0071] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0072] Embodiment 1

[0073] The schematic diagram of the power conversion circuit 1a disclosed in the present invention is as follows Figure 1 As shown, the power conversion circuit 1a includes an input end and an output end, the input end includes an input positive end Vin+ and an input negative end Vin-, and the output end includes an output positive end Vo+ and an output negative end Vo-. In this embodiment, the input negative end Vin- and the output negative end Vo- are electrically connected to the ground end GND; Figure 1The circuit topology diagram shown also includes two three-switch bridge arms, a transformer component 4, a resonant capacitor Cr and an equivalent resonant inductor Llk, and also includes at least one input capacitor Cin and at least one output capacitor Co. Each three-switch bridge arm includes three switch tubes electrically connected in series, and the two three-switch bridge arms are respectively a first switch bridge arm 11a and a second switch bridge arm 11b, wherein the first switch bridge arm 11a includes an upper switch Q1, a middle switch Q2 and a lower switch SR1, the upper switch Q1 and the middle switch Q2 are electrically connected to an upper node A1, and the middle switch Q2 and the lower switch SR1 are electrically connected to a lower node B1; the second switch bridge arm 11b includes an upper switch Q3, a middle switch Q4 and a lower switch SR2, the upper switch Q3 and the middle switch Q4 are electrically connected to an upper node A2, and the middle switch Q4 and the lower switch SR2 are electrically connected to a lower node B2. The transformer assembly 4 includes a high-voltage winding W1 (i.e., the third winding), a low-voltage winding W21 (i.e., the first winding) and a low-voltage winding W22 (i.e., the second winding), wherein the high-voltage winding W1 is connected in series with a series resonant circuit composed of a resonant capacitor Cr and an equivalent resonant inductor Llk to form a series branch, which is bridged between the upper node A1 and the upper node A2; further, the first end of the high-voltage winding W1 is short-circuited with the equivalent resonant inductor Llk, and the second end of the high-voltage winding W1 is short-circuited with the resonant capacitor Cr. The second end of the low-voltage winding W21 and the second end of the low-voltage winding W22 are electrically connected to the output positive terminal Vo+, the first end of the low-voltage winding W21 is electrically connected to the lower node B1, and the first end of the low-voltage winding W22 is electrically connected to the lower node B2; the first end of the low-voltage winding W21, the second end of the low-voltage winding W22 and the second end of the high-voltage winding are the same-name terminals (i.e., the same polarity), marked as point terminals, the second end of the low-voltage winding W21, the first end of the low-voltage winding W22 and the first end of the high-voltage winding are the same-name terminals (i.e., the same polarity), marked as non-point terminals; at least one output capacitor Co is connected across the output positive terminal Vo+ and the ground terminal GND; the equivalent resonant inductor Llk can be a parasitic leakage inductance of a magnetic component, can be an external inductor, or can be a combination of an external inductor and a parasitic leakage inductance of a magnetic component.

[0074] One end of at least one input capacitor Cin is electrically connected to the input positive terminal Vin+, and the other end is electrically connected to the output positive terminal Vo+, so that part of the output current ripple generated by the two low-voltage windings flows into the output capacitor Co, and the other part flows into the input capacitor Cin, and is supplied to the two three-switch bridge arms through the input capacitor Cin, so that the ripple current flowing into the output capacitor Co can be reduced, that is, the capacitance of the output capacitor Co or the number of output capacitors Co can be reduced, so as to further reduce the volume of the power module. In other embodiments, the input capacitor Cin can also be connected across the input positive terminal Vin+ and the ground terminal GND.

[0075] Figure 1In the switch tube of the power conversion circuit 1a shown, the upper switch Q1, the middle switch Q4 and the lower switch SR1 are turned on and off synchronously, and the upper switch Q3, the middle switch Q2 and the lower switch SR2 are turned on and off synchronously. In detail, the turn-on duty ratio of the upper switch Q1 and the upper switch Q3 is close to 50%; and the turn-on interval of the upper switch Q1 is 180 degrees out of phase with the turn-on interval of the upper switch Q3.

[0076] The present invention discloses a Figure 2A The power conversion device shown in FIG. Figure 1 The power conversion circuit 1a shown in the figure includes a pre-charging unit 2a, a current sampling unit 3a and at least one sampling resistor Rc. The pre-charging unit 2a includes three ports, namely, a switch terminal Pr1, an inductor terminal Pr2 and a ground terminal G, the ground terminal G is electrically connected to the ground terminal GND of the power conversion circuit 1a, the switch terminal Pr1 is electrically connected to the input positive terminal Vin+, the inductor terminal Pr2 is electrically connected to one end of the sampling resistor Rc, and the other end of the sampling resistor Rc is electrically connected to the output positive terminal Vo+ of the power conversion circuit 1a. The pre-charging unit 2a pre-charges the output capacitor Co in the power conversion circuit 1a, so that before the power conversion circuit 1a is started, the energy of the input terminal Vin is converted by the pre-charging unit to pre-charge the voltage across the output capacitor Co to a predetermined voltage, which is specifically any voltage between 70% of the output steady-state voltage Vo_normal of the power conversion circuit 1a and the output steady-state voltage Vo_normal. When the power conversion circuit 1a starts, the voltage across the output capacitor Co is close to the output steady-state voltage Vo_normal, which not only avoids the impact current generated by the high voltage difference at both ends of the series circuit composed of the resonant capacitor Cr and the equivalent resonant inductor Llk flowing through the two switch bridge arms and causing damage to the switch tube; but also reduces the voltage resistance requirements of the two upper switches Q1 and Q2.

[0077] like Figure 2A In the embodiment shown, the pre-charging unit 2a includes two pre-charging switches Qc1 and Qc2, a pre-charging inductor Lc1, a pre-charging capacitor Cc1 and a pre-charging diode Dc1. Among them, the drain of the pre-charging switch Qc1 is electrically connected to the switch terminal Pr1, the source of the pre-charging switch Qc1 is electrically connected to the drain of the pre-charging switch Qc2, and the source of Qc2 is electrically connected to the ground terminal G; the first end of the pre-charging inductor Lc1 is electrically connected to the source of the pre-charging switch Qc1, the other end of the pre-charging inductor Lc1 is electrically connected to the positive electrode of the pre-charging diode Dc1 and the positive end of the pre-charging capacitor Cc1, the negative end of the pre-charging capacitor Cc1 is electrically connected to the ground terminal G, and the negative electrode of the pre-charging diode Dc1 is electrically connected to the inductor terminal Pr2. The pre-charging unit 2a disclosed in this embodiment is simple to implement and has a small size; the implementation method of the pre-charging unit is not limited to Figure 2A The circuit topology shown is acceptable as long as it can achieve the function.

[0078] The present invention also discloses a schematic diagram of a current sampling unit combination and a power conversion device using the current sampling unit combination. Figure 2A and Figure 2B As shown, the current sampling unit combination includes a current sampling resistor Rc and a current sampling unit 3. The current sampling resistor Rc is electrically connected in series between the inductor terminal Pr2 of the pre-charging unit 2 and the output positive terminal Vo+ of the power conversion circuit 1a; the input end of the current sampling resistor Rc is short-circuited with the inductor terminal Pr2 of the pre-charging unit 2, and the output end of the current sampling resistor Rc is short-circuited with the output positive terminal Vo+ of the power conversion circuit 1a. During the pre-charging process, the charging current of the pre-charging unit 2 to the output capacitor Co flows through the sampling resistor Rc, and the voltage drop Vcs_pr across the sampling resistor Rc reflects the magnitude of the pre-charging current.

[0079] The current sampling unit 3 includes three sampling terminals S1 / S2 / S3, a reference voltage terminal Vr1, a sampling output positive terminal Vcs1+ and a sampling output negative terminal Vcs1-. The sampling terminals S1 and S2 are respectively electrically connected to the first end of a corresponding low-voltage winding; the sampling terminal S3 is electrically connected to one end (i.e., Vo+) of the current sampling resistor Rc. The reference voltage terminal Vr1 is electrically connected to the output positive terminal Vo+, and the voltage between the sampling output positive terminal Vcs1+ and the sampling output negative terminal Vcs1- is the sampling output voltage Vcs1.

[0080] Before the power conversion circuit 1a is started, the pre-charging unit 2 charges the output capacitor Co, and the current flowing through the sampling resistor Rc is the pre-charging current; at the same time, the voltage drop across the low-voltage winding W21 and the low-voltage winding W22 is zero, and the sampling output voltage Vcs of the current sampling unit combination only reflects the size of the pre-charging working current. After the power conversion circuit 1a is started, the pre-charging unit 2 stops working, and the voltage drop across the sampling resistor Rc is zero. At this time, the sampling output voltage Vcs of the current sampling unit 2 reflects the sum of the working currents of the low-voltage windings W21 and W22. The above principle enables the sampled output voltage Vcs of the current sampling unit combination to reflect not only the working current of the power conversion circuit 1a, but also the pre-charging current of the pre-charging unit 2a to the output capacitor Co before the power conversion circuit 1a starts; when the sampled output voltage Vcs is used as the input signal of the detection and protection circuit, it can not only detect and protect the abnormal working current of the power conversion circuit 1a, but also detect and protect the abnormal pre-charging current during the charging process of the output capacitor Co. In this way, the current is fully detected and protected during the operation of the power conversion device.

[0081] like Figure 2AAs shown, the current sampling unit 3a disclosed in this embodiment includes three sampling resistors R1, R2 and R3, an impedance matching resistor R6, a sampling capacitor C1 and an amplification unit 31. One end of the sampling resistor R1, one end of the sampling resistor R2 and one end of the sampling resistor R3 are electrically connected to the midpoint F of the sampling resistor, and the other ends of the sampling resistors R1, R2 and R3 are electrically connected to the sampling terminal S1, the sampling terminal S2 and the sampling terminal S3 respectively; one end of the sampling capacitor C1 is connected to the midpoint F of the sampling resistor, and the other end is connected to the reference terminal Vr1 through the impedance matching resistor R6; the two ends of the sampling capacitor C1 are two sampling output terminals. The amplification unit 31 includes an amplification reference terminal, an amplification input positive terminal, an amplification input negative terminal and an amplification output terminal. The amplification reference terminal (i.e., the sampling output negative terminal Vcs1-) is electrically connected to the output negative terminal Vo- of the power conversion circuit 1a; the amplification input positive terminal is electrically connected to a sampling output terminal, i.e., the midpoint F of the sampling resistor, and the amplification input negative terminal is electrically connected to another sampling output terminal. The current sampling signal Vcs1 is output between the amplification output terminal and the amplification reference terminal of the amplification unit 31. The current sampling signal Vcs1 is proportional to the voltage across the sampling capacitor C1.

[0082] In another embodiment, the power conversion device may be used as follows Figure 2C In the current sampling unit 3 b shown, the amplifying unit 32 of the current sampling unit 3 b is a specific implementation circuit of the amplifying unit 31 of the current sampling unit 3 a. Figure 2C In the embodiment shown, the amplification unit 32 includes an operational amplifier OP, a second resistor R20, a third resistor R30, a fourth resistor R40 and a fifth resistor R50; the second resistor R20 is connected between the positive input terminal of the operational amplifier OP and one end of the sampling capacitor C1, that is, the midpoint F of the sampling resistor; the third resistor R30 is connected between the positive input terminal of the operational amplifier OP and the reference terminal of the operational amplifier OP, that is, the negative output terminal Vo- of the power conversion circuit 1a; the fourth resistor R40 is connected between the other end of the sampling capacitor C1 and the negative input terminal of the operational amplifier OP; the fifth resistor R50 is connected between the positive input terminal of the operational amplifier OP and the reference terminal of the operational amplifier OP, that is, the negative output terminal Vo- of the power conversion circuit 1a; the fourth resistor R40 is connected between the other end of the sampling capacitor C1 and the negative input terminal of the operational amplifier OP; 0 is connected between the output terminal and the negative input terminal of the operational amplifier OP, and the resistance satisfies the relationship R30 / (R20+(R1 / / R2 / / R3))=R50 / (R40+R6), where R1 / / R2 / / R3 represents the parallel resistance of the sampling resistor R1, the sampling resistor R2 and the sampling resistor R3, R20 is the resistance of the second resistor, R30 is the resistance of the third resistor, R40 is the resistance of the fourth resistor, R50 is the resistance of the fifth resistor, and the impedance matching resistor R6 is the resistance of the impedance matching resistor=R1 / / R2 / / R3. The operational amplifier reference terminal Vcs1- in this embodiment can be connected to the negative output terminal Vo- of the power conversion circuit 1a, or to a reference potential; when the voltage across the sampling capacitor C1 is zero, the voltage of the sampling output terminal Vcs1+ to the negative output terminal Vo- of the power conversion circuit 1a includes a bias voltage, and the bias voltage is the reference potential voltage.

[0083] The implementation circuit of the amplification unit 32 is not limited to the following Figure 2A and Figure 2C As shown, it is sufficient as long as the current sampling signal Vcs1 output by the amplifying unit is proportional to the voltage across the sampling capacitor C1.

[0084] The current sampling scheme disclosed in the present invention is not limited to the following Figure 1 The power conversion circuit shown can be referenced Figure 2B As shown, as long as it includes two lower switches, two low-voltage windings, an output capacitor Co, a pre-charging unit 2, a current sampling resistor Rc connected between the pre-charging unit 2 and the output capacitor Co, and a circuit unit 50, it satisfies the following conditions: Figure 2B The connection method shown can be used to apply the current sampling solution disclosed in the present invention. Figure 2B In the embodiment, the first end of the circuit unit 50 is electrically connected to the positive input terminal Vin+ of the power conversion circuit 1a, and the second end and the third end of the circuit unit 50 are electrically connected to the lower node B1 and the lower node B2 of the power conversion circuit 1a, respectively. In addition, the second end and the third end of the circuit unit 50 can also be electrically connected together to the negative input terminal Vin- of the power conversion circuit 1a; or the second end and the third end of the circuit unit 50 can also be electrically connected together to the positive output terminal Vo+ of the power conversion circuit 1a; or the second end of the circuit unit 50 is electrically connected to one of the lower node B1 and the lower node B2, and the third end of the circuit unit 50 is electrically connected to one of the positive output terminal Vo+ or the negative output terminal Vo- of the power conversion circuit 1a.

[0085] The power conversion device disclosed in the present invention further comprises a driving unit 4a, which is as follows Figure 1 The upper switches Q1 / Q3, the middle switches Q2 / Q4 and the lower switches SR1 / SR2 shown provide drive signals. Figure 3AAs shown, the driving unit 4 a includes a lower switch driving unit 41 , a middle switch driving unit 42 , an upper switch driving unit 43 and a driving magnetic member 44 . The lower switch driving unit 41 includes a driving power supply positive terminal Vdrv, a ground terminal GND, a lower switch driving output terminal Lo1 / Lo2 and four control switches Q11 / Q12 / Q13 / Q14, wherein the source terminal of the control switch Q11 and the drain terminal of Q12 are connected in series to the lower switch driving output terminal Lo1, the drain terminal of the control switch Q11 is electrically connected to the driving power supply positive terminal Vdrv, and the source terminal of the control switch Q12 is electrically connected to the ground terminal GND; the source terminal of the control switch Q13 and the drain terminal of Q14 are connected in series to the lower switch driving output terminal Lo2, the drain terminal of the control switch Q13 is electrically connected to the driving power supply positive terminal Vdrv, and the source terminal of the control switch Q14 is electrically connected to the ground terminal GND, that is, the four control switches are electrically connected to form a full-bridge structure and are bridged between the driving power supply positive terminal and the ground terminal, and the first lower switch driving output terminal and the second lower switch driving output terminal are respectively the midpoints of the two bridge arms. FIG. 3B to FIG. 3D As shown, it includes a first control signal PWM1, a second control signal PWM2, a third control signal PWM3 and a fourth control signal PWM4. The first control signal PWM1 is used to control the on and off of the switch Q11, the second control signal PWM2 is used to control the on and off of the switch Q13, the third control signal PWM3 is used to control the on and off of the switch Q12, and the fourth control signal PWM4 is used to control the on and off of the switch Q14. The voltage of the lower switch drive output Lo1 is used to drive the lower switch SR1, and the voltage of the lower switch drive output Lo2 is used to drive the lower switch SR2. The driving magnetic part 44 includes a driving winding W31, a first middle winding W41, a second middle winding W42, a first upper winding W43 and a second upper winding W44. The driving winding W31, the first middle winding W41, the second middle winding W42, the first upper winding W43 and the second upper winding W44 are wound on the same transformer core; the first end of the driving winding W31, the second end of the first middle winding W41, the first end of the second middle winding W42, the first end of the first upper winding W43 and the second end of the second upper winding W44 are the same-named ends, marked as point ends. The first end of the driving winding W31 is electrically connected to the lower switch driving output Lo1, and the second end of W31 is electrically connected to the lower switch driving output Lo2.

[0086] The middle switch driving unit 42 includes middle drive switches Q21, Q22, Q23 and Q24. The drain of the middle drive switch Q21 is electrically connected to the first end of the first middle winding W41 and is electrically connected to the gate of the middle switch Q2 of the power conversion circuit 1a (i.e., the middle switch driving output Mo1), the drain of the middle drive switch Q22 is electrically connected to the second end of the first middle winding W41, and the sources of the middle drive switches Q21 and Q22 are electrically connected in parallel to the lower node B1 of the power conversion circuit 1a. The voltage between the first end of the first middle winding W41 and the lower node B1 is used to control the opening and closing of the middle drive switch Q22, so that when the first end voltage of the first middle winding W41 is a positive voltage relative to the second end voltage, the middle drive switch Q22 is turned on, and the middle switch drive output Mo1 is a positive voltage relative to the lower node B1, and is approximately equal to the voltage across the first middle winding W41; the voltage between the second end of the first middle winding W41 and the lower node B1 is used to control the opening and closing of the middle drive switch Q21, so that when the second end voltage of the first middle winding W41 is a positive voltage relative to the first end voltage, the middle drive switch Q21 is turned on, and the middle switch drive output Mo1 is a zero voltage relative to the lower node B1. The drain of the middle drive switch Q23 is electrically connected to the first end of the second middle winding W42, and is electrically connected to the gate of the middle switch Q4 of the power conversion circuit 1a (i.e., the middle switch drive output Mo2). The drain of the middle drive switch Q24 is electrically connected to the second end of the second middle winding W42, and the sources of the middle drive switches Q23 and Q24 are electrically connected in parallel to the lower node B2 of the power conversion circuit 1a. The voltage between the first end of the second middle winding W42 and the lower node B2 is used to control the opening and closing of the middle drive switch Q24, so that when the first end voltage of the second middle winding W42 is a positive voltage relative to the second end voltage, the middle drive switch Q24 is turned on, and the middle switch drive output Mo2 is a positive voltage relative to the lower node B2, and is approximately equal to the voltage across the second middle winding W42; the voltage between the second end of the second middle winding W42 and the lower node B2 is used to control the opening and closing of the middle drive switch Q23, so that when the second end voltage of the second middle winding W42 is a positive voltage relative to the first end voltage, the middle drive switch Q23 is turned on, and the middle switch drive output Mo2 is a zero voltage relative to the lower node B2.

[0087] The upper switch driving unit 43 includes upper driving switches Q25, Q26, Q27 and Q28. The drain of the upper driving switch Q25 is electrically connected to the first end of the first upper winding W43 and is electrically connected to the gate of the upper switch Q1 of the power conversion circuit 1a (i.e., the upper switch driving output Ho1), the drain of the upper driving switch Q26 is electrically connected to the second end of the first upper winding W43, and the sources of the upper driving switches Q25 and Q26 are electrically connected in parallel to the upper node A1 of the power conversion circuit 1a. The voltage between the first end of the first upper winding W43 and the upper node A1 is used to control the opening and closing of the upper drive switch Q26, so that when the first end voltage of the first upper winding W43 is a positive voltage relative to the second end voltage, the upper drive switch Q26 is turned on, and the upper switch drive output Ho1 is a positive voltage relative to the upper node A1 voltage, and is approximately equal to the voltage across the first upper winding W43; the voltage between the second end of the first upper winding W43 and the upper node A1 is used to control the opening and closing of the upper drive switch Q25, so that when the second end voltage of the first upper winding W43 is a positive voltage relative to the first end voltage, the upper drive switch Q25 is turned on, and the upper switch drive output Ho1 is a zero voltage relative to the upper node A1 voltage. The drain of the upper drive switch Q27 is electrically connected to the first end of the second upper winding W44, and is electrically connected to the gate of the upper switch Q3 of the power conversion circuit 1a (i.e., the upper switch drive output Ho2). The drain of the upper drive switch Q28 is electrically connected to the second end of the second upper winding W44, and the sources of the upper drive switches Q27 and Q28 are electrically connected in parallel to the upper node A2 of the power conversion circuit 1a. The voltage between the first end of the second upper winding W44 and the upper node A2 is used to control the opening and closing of the upper drive switch Q28, so that when the first end voltage of the second upper winding W44 is a positive voltage relative to the second end voltage, the upper drive switch Q28 is turned on, and the upper switch drive output Ho2 is a positive voltage relative to the upper node A2 voltage, and is approximately equal to the voltage across the second upper winding W44; the voltage between the second end of the second upper winding W44 and the upper node A2 is used to control the opening and closing of the upper drive switch Q27, so that when the second end voltage of the second upper winding W43 is a positive voltage relative to the first end voltage, the upper drive switch Q27 is turned on, and the upper switch drive output Ho2 is a zero voltage relative to the upper node A2 voltage.

[0088] Detailed control signals such as Figure 3B , Figure 3C and Figure 3D As shown. Figure 3BThe duty cycle of the first control signal PWM1 and the second control signal PWM2 is a fixed duty cycle, and the duty cycle is any value in the range of 40%≤D<50%; the first control signal PWM1 and the second control signal PWM2 are 180 degrees out of phase, respectively controlling the control switches Q11 and Q13; the third control signal PWM3 is the same as the second control signal PWM2, and is used to control the control switch Q12; the fourth control signal PWM4 is the same as the first control signal PWM1, and is used to control the control switch Q14. The time from time 0 to time t4 is a switching cycle Ts, wherein the interval t1-t2 and the interval t3-t4 are dead time; in the interval 0-t1, the first control signal PWM1 and the fourth control signal PWM4 are high level, corresponding to the control switch Q11 and Q14 being turned on respectively; the second control signal PWM2 and the third control signal PWM3 are low level, corresponding to the control switch Q13 and Q12 being turned off respectively; so that the voltage drop V(Lo1-Lo2) across the driving winding W31 is a positive voltage; in the interval t2-t3, the second control signal PWM2 and the third control signal PWM3 are high level. The first control signal PWM1 and the fourth control signal PWM4 are low levels, corresponding to the control switches Q13 and Q12 being turned on respectively; the first control signal PWM1 and the fourth control signal PWM4 are low levels, corresponding to the control switches Q11 and Q14 being turned off respectively; making the voltage drop V(Lo1-Lo2) across the drive winding W31 a negative voltage; in the dead zone t1-t2, the magnetizing current of the drive winding W31 extracts the charge of the equivalent junction capacitance Cds across the control switch Q12, and charges the equivalent junction capacitance Cds across the control switch Q14, making V(Lo1-Lo2) first drop from Vdrv to zero; and further drop from zero to -Vdrv. In the dead zone t3-t4, the magnetizing current of the drive winding W31 charges the equivalent junction capacitance Cds across the control switch Q12, and extracts the charge of the equivalent junction capacitance Cds across the control switch Q14, making V(Lo1-Lo2) first rise from -Vdrv to zero; and further rise from zero to +Vdrv. Figure 3B The driving control method shown makes the voltage drop V(Lo1-Lo2) across the driving winding W31 only have positive voltage and negative voltage. In order to ensure the necessary dead time between the switches in the power conversion circuit 1a so that each switch in the power conversion circuit 1a can achieve soft switching, the magnetizing current of the driving winding is controlled not to be too large, so that the speed at which the magnetizing current extracts the gate charge of the switch cannot be too fast; the side effect of this approach is that the switch of the power conversion circuit 1a is turned off too slowly, making the switch turn-off loss too high.

[0089] In another embodiment, if Figure 3CAs shown, the duty cycles of the first control signal PWM1 and the second control signal PWM2 are fixed duty cycles, and the duty cycle is any value within the range of 40% ≤ D < 50%. The first control signal PWM1 and the second control signal PWM2 are out of phase by 180 degrees, respectively controlling the control switches Q11 and Q13; the third control signal PWM3 approximately satisfies a complementary relationship with the first control signal PWM1 to control the control switch Q12; the fourth control signal PWM4 approximately satisfies a complementary relationship with the second control signal PWM2 to control the control switch Q14. The time from time 0 to time t8 is a switching period, and the intervals t1 - t4 and t5 - t8 are dead times. Taking the interval t1 - t4 as an example to illustrate the characteristics of the dead time, the interval t5 - t8 can be simply deduced. Within the interval t1 - t2, the magnetizing current of the driving winding W31 extracts the charge of the equivalent junction capacitance Cds at both ends of the control switch Q12, causing V(Lo1 - Lo2) to first drop from Vdrv to zero; within the interval t2 - t3, since the two control switches Q12 and Q14 are in the conducting state, the terminal voltage V(Lo1 - Lo2) across the driving winding W31 is zero; within the interval t3 - t4, the magnetizing current of the driving winding W31 charges the equivalent junction capacitance Cds at both ends of the control switch Q14, causing V(Lo1 - Lo2) to drop from zero to -Vdrv. In this embodiment, the terminal voltage V(Lo1 - Lo2) across the driving winding W31 can be a positive voltage, a zero voltage, and a negative voltage. Here, the zero voltage intervals (i.e., the intervals t2 - t3 and t6 - t7) in V(Lo1 - Lo2) are the overlapping regions of the high potentials of the third control signal PWM3 and the fourth control signal PWM4, and the driving winding W31 conducts freewheeling through the two control switches Q12 and Q14. The existence of the zero voltage intervals in V(Lo1 - Lo2) can make the length of the dead time of the switching tubes in the power conversion circuit 1a not affect the turn-off speed of the switching tubes in the power conversion circuit 1a, that is, it can reduce the turn-off time of the switching tubes, reduce the turn-off loss of the switching tubes, and ensure the dead time required for the soft switching of each power switch in the power conversion circuit 1a, improving the conversion efficiency of the power conversion device.

[0090] In another embodiment, as Figure 3D shown, the duty cycles of the first control signal PWM1 and the second control signal PWM2 are fixed duty cycles, and the duty cycle is any value within the range of 50% < D ≤ 60%. The time from time 0 to time t8 is a switching period, and the intervals t1 - t4 and t5 - t8 are dead times. The time from time 0 to time t8 is a switching period, and the intervals t1 - t4 and t5 - t8 are dead times. In this embodiment, the characteristics of the two dead time intervals within one switching period are the same as those of Figure 3CThe same as shown, will not be repeated here; the difference is that the zero voltage interval in the terminal voltage V(Lo1-Lo2) in this embodiment is the overlapping area of ​​the high potential of the first control signal PWM1 and the high potential of the second control signal PWM2, and the driving winding W31 is freewheeling via two control switches Q11 and Q13.

[0091] The power conversion device disclosed by the present invention has an input capacitor Cin and an output capacitor Co electrically connected in series. When the input voltage Vin rises, the output voltage Vo will also rise even when the power conversion device has not entered the working mode, causing a residual voltage problem at the output end. At this time, it is necessary to add a dummy load unit 5a at the output end of the power conversion device. When the power conversion device has not yet entered the working state, the dummy load unit 5a is cut in so that it is bridged between the output positive terminal Vo+ and the output negative terminal Vo- (i.e., the ground terminal GND) of the power conversion device to consume the residual voltage at the output end; and when the power conversion device enters the working state, the dummy load unit 5a is cut out so that it does not increase the loss of the power conversion device.

[0092] The embodiment of the dummy load unit 5a disclosed in the present invention is as follows: Figure 4 As shown, it includes a dummy load control switch Q51, a dummy load control switch Q52, a dummy load amplifying switch Q53 and current limiting resistors R51 to R54. Among them, the drain of the dummy load control switch Q51 is connected in series with one end of the current limiting resistor R51, the source of the dummy load control switch Q51 is electrically connected to the output negative terminal Vo-, the gate of the dummy load control switch Q51 receives a dummy load control signal Loadoff, and the other end of the current limiting resistor R51 is electrically connected to the power supply voltage Vcc (Vcc can be 5V or 3.3V); the gate of the dummy load control switch Q52 is electrically connected to the drain of the dummy load control switch Q51, and the drain of the dummy load control switch Q52 is electrically connected to one end of the current limiting resistor R52 The other end of the current limiting resistor R52 is electrically connected to the power supply voltage Vcc, the source of the dummy load control switch Q52 is electrically connected to one end of the current limiting resistor R53, and the other end of the current limiting resistor R53 is electrically connected to the output negative terminal Vo-; the base of the dummy load amplifier switch Q53 is electrically connected to the source of the dummy load control switch Q52, the collector of the dummy load amplifier switch Q53 is electrically connected to the output positive terminal Vo+ of the power conversion circuit 1a, the emitter of the dummy load amplifier switch Q53 is electrically connected to one end of the current limiting resistor R54, and the other end of the current limiting resistor R54 is electrically connected to the output negative terminal Vo-.

[0093] When the dummy load control signal Loadoff is at a high level (5V or 3.3V), it indicates that the power conversion device is about to start working. At this time, the dummy load unit 5a needs to be cut out from the output of the power conversion device, so that the amplifier switch Q53 is turned off. When the dummy load control signal Loadoff is at a low level, the dummy load unit 5a needs to be cut into the output of the power conversion device, specifically, the dummy load control switch Q51 is turned off, and the dummy load control switch Q52 is turned on, so that the current Ice (collector and emitter) flowing through the dummy load amplifier switch Q53 is N times the current Ibe (base and emitter). Here, the magnitude of the current Ice can be set by the resistance value of the current limiting resistors R52, R53 and R54 so that the amplifier switch Q53 is in an amplified or turned-on state.

[0094] In practical applications, the dummy load control signal Loadoff is jointly determined by the start signal of the power conversion device and the output voltage Vo. When the start signal of the power conversion device is at a high level, the power conversion circuit 1a will start working, and the dummy load control signal Loadoff needs to be set to a high level so that the dummy load unit 5a is cut out from the output of the power conversion device. When the start signal of the power conversion device is at a low level, it is necessary to simultaneously determine the size of the output voltage Vo; when the output voltage Vo is less than a preset voltage Vref, it is necessary to set the dummy load control signal Loadoff to a low level so that the dummy load unit 5a is cut into the output of the power conversion device to discharge the output voltage. When the start signal of the power conversion device is at a low level and the output voltage Vo is greater than or equal to a preset voltage Vref, the dummy load control signal Loadoff needs to be set to a high level so that the dummy load unit 5a is cut out from the output of the power conversion device; this situation usually occurs when the power conversion device includes two or more power conversion circuits in parallel; taking the parallel application of two power conversion circuits 1a and 1b as an example, when the control signal Load off for controlling the dummy load corresponding to the power conversion circuit 1a is at a low level, it is necessary to simultaneously judge the size of the output voltage Vo. When the output voltage Vo is greater than or equal to the preset voltage Vref, it means that the power conversion circuit 1b is in a normal working state, and the dummy load unit 5a needs to be cut out from the output of the power conversion device.

[0095] As the functions of power conversion devices increase, the controller or microprocessor often faces the situation of insufficient pins. The present invention time-shares the current-sharing bus function of the power conversion device and the address function of the power management bus (PMBus) on a pin of the controller or microprocessor (MCU); the time-shared pin needs to have both the current source output capability and the A / D conversion capability of the pin voltage. In this embodiment, the address function of the power management bus (PMBus) is completed after the microprocessor MCU is powered on and initialized, and the current-sharing bus function starts working after the power conversion device receives the start signal of the output voltage; therefore, the time-shared multiplexing method is adopted, that is, a small-sized microprocessor MCU with a limited number of pins can be used, and the complex functional requirements of the power conversion device can be met. Detailed methods, such as Figure 5The gating circuit 6a shown includes a gating switch 60, which includes a power supply terminal Vc, a ground terminal G, a control terminal S, input terminals in1 and in2, and an output terminal out; the input terminals in1 and in2 are respectively electrically connected to the current sharing bus IMON pin of the power conversion device and the address function ADDR0 pin of the power management bus (PMBus), and the output terminal out is connected to the IMON / ADDR0 pin of the microprocessor MCU. When the voltage at the control terminal S is at a low level (i.e., before the power conversion device is started), the current sharing switch Q62 is turned off and the address switch Q61 is turned on, and the current source of the gating switch 60 generates a voltage signal ADDR0 on the input terminal in2, and the voltage signal is connected to the output terminal out, that is, the voltage at the output terminal out represents the address function ADDR0 signal of the power management bus (PMBus). Here, the voltage at the control terminal S can be the start-up control signal of the power conversion device. When the voltage at the control terminal S is at a high level (i.e. after the power conversion device is started), the current balancing switch Q62 is turned on and the address switch Q61 is turned off, and the current source of the selection switch 60 generates a voltage signal IMON at the input terminal in1, and the voltage signal is connected to the output terminal out, that is, the voltage at the output terminal out represents the IMON signal of the current balancing bus. The input terminal in2 is electrically connected to the address circuit unit (including the address capacitor and the address resistor), that is, the input terminal in2 is externally connected to the address capacitor C61 and the address resistor R61 connected in parallel; the input terminal in1 is electrically connected to the current balancing circuit unit (including the current balancing resistor, the current balancing capacitor and the current balancing switch), that is, the input terminal in1 is externally connected to the current balancing capacitor C62 and the current balancing resistor R62 connected in parallel and a ground switch Q63, one end of the ground switch Q63 is electrically connected to the current balancing capacitor C62 and the current balancing resistor R62, and the other end is grounded. When multiple power conversion devices are used in parallel, the input terminals in1 of multiple gating circuits 60 are also short-circuited in parallel to form a current-sharing busbar of the multiple power conversion devices, reflecting the working current amplitude information of the multiple power conversion devices, which can be used for the current-sharing function or current information reporting function of the multiple power conversion devices. When only some of the multiple power conversion devices are in normal working state, it is necessary to cut off the current-sharing resistor R62 of the power conversion device in the non-working state from the input terminal in1 to avoid the current-sharing resistor R62 of the power conversion device in the non-working state affecting the working voltage amplitude on the current-sharing busbar. The voltage of the control terminal S can be used to control the opening and closing of the ground switch Q63. When the ground switch Q63 is turned off, the input terminal in1 is in a high-impedance state, that is, the current-sharing resistor R62 is cut off from the input terminal in1, which does not affect the working voltage amplitude on the current-sharing busbar of other working parallel power conversion devices.

[0096] In this embodiment, the gating circuit 60 can be implemented by an independent device or multiple devices. For example, the current source can be in the microprocessor MCU and connected to the IMON / ADDR0 pin of the microprocessor MCU. The present invention is not limited to this, as long as the technical features and technical effects disclosed by the present invention are met, it is within the protection scope of the present invention.

[0097] Application power conversion circuit 1 and Figure 3A The structural layout and the magnetic core explosion diagram of the power conversion device a of the drive unit 4a are shown in FIG. Figures 6A to 6D As shown; among them, Fig. 6A and Figure 6C It is a top view. Figure 6B and 6D The power conversion device a includes a circuit substrate 10, a transformer core 20, upper switches Q1 and Q3, middle switches Q2 and Q4, lower switches SR1 and SR2, a resonant capacitor Cr, an output capacitor Co, an input capacitor Cin, a drive unit 4a, an input positive terminal Vin+, an output negative terminal Vo+, an output negative terminal Vo- (i.e., a ground terminal GND), and a signal terminal signal.

[0098] like FIG. 6A to FIG. 6D As shown, the circuit substrate 10 includes a first surface 101 and a second surface 102 opposite to each other, and also includes holes 73 and 74 and a hole 75. The holes 73 and 74 and the hole 75 penetrate the first surface 101 and the second surface 102. The hole 75 is surrounded by the circuit substrate 10 on all sides. At least one side of the holes 73 and 74 is open, and the other sides are surrounded by the circuit substrate. The design of the holes can minimize the surface area occupied by the circuit substrate 10 and reduce the volume of the power conversion device. In another embodiment, the holes 73 and 74 can also be designed as holes like the hole 75, and are surrounded by the circuit substrate 10 on all sides. Fig. 6A The layout of the first surface 101 of the circuit substrate 10 is shown. Figure 6BThe layout of the second surface 102 of the circuit substrate 10 is shown. The first surface 101 of the circuit substrate 10 includes a port area 110, an output capacitor area 111, a switch area 112, a transformer core area 113, a resonant capacitor area 114, a lower switch driving area 120, and middle and upper switch driving areas 121 and 122. The input positive terminal Vin+, the output negative terminal Vo+, the output negative terminal Vo- (i.e., the ground terminal GND) and the signal terminal signal are arranged in the port area 110; the port area 110 is realized by using a process of electroplating gold fingers on a PCB on one side of the first surface 101 of the circuit substrate 10. The output capacitor Co is arranged in the output capacitor area 111; the upper switch Q1 / Q3, the middle switch Q2 / Q4 and the lower switch SR1 / SR2 are arranged in the switch area 112; a part of the transformer core 20 is arranged in the transformer core area 113; the resonant capacitor Cr is arranged in the resonant capacitor area 114; as shown in FIG. Figure 3A Part of the components of the driving unit 4a shown are arranged in the lower switch driving area 120 and the middle and upper switch driving areas 121 and 122; the input capacitor Cin is arranged in the middle and upper switch driving areas 121 and 122. The second surface 102 of the circuit substrate 10 includes a port area 210, an output capacitor area 211, a switch area 212, a transformer core area 213, a resonant capacitor area 214, and middle and upper switch driving areas 221 and 222. The input positive terminal Vin+, the output negative terminal Vo+, the output negative terminal Vo- (i.e., the ground terminal GND) and the signal terminal signal are arranged in the port area 210; the port area 210 is realized by using a process of electroplating gold fingers on a PCB on one side of the first surface 102 of the circuit substrate 10; the projection of the port area 210 and the port area 110 on the first surface 102 completely or partially overlap. The output capacitor Co is arranged in the output capacitor area 211; the middle switch and the lower switch are arranged in the switch area 212; a part of the transformer core 20 is arranged in the transformer core area 213; the resonant capacitor Cr is arranged in the resonant capacitor area 214; Figure 3A Part of the components of the driving unit 4a shown in the figure are arranged in the lower switch driving area 220; the input capacitor Cin is arranged in the middle and upper switch driving areas 221 and 222. In this embodiment, the transformer core area 113, the switch area 112, the output capacitor area 111 and the port area 110 are arranged in the same direction (such as Fig. 6A or the transformer core region 113, the switch region 112, the resonant capacitor region 114 and the port region 110 are arranged in the same direction (eg, Fig. 6A The y-axis direction shown in the figure) is arranged in sequence; it can be combined with Figure 1As shown in the power conversion circuit shown, each end of the winding in the transformer component 4 is connected to the corresponding switch tube, or is connected to the corresponding resonant capacitor, or is connected to the corresponding output capacitor Co; further, the two ends of the output capacitor and one end or both ends of the winding in the transformer component 4 are connected to the output positive terminal Vo+ and the output negative terminal Vo- of the port area 110, so that the current path formed by the winding, switch tube, resonant capacitor Cr, output capacitor Co, output positive terminal Vo+ and output negative terminal Vo- in the transformer component 4 is the shortest, reducing the parasitic impedance on the current path, thereby improving the conversion efficiency of the power conversion device.

[0099] Detailed, combined Figure 6C The first surface detailed layout diagram and Fig.6D In the detailed layout diagram of the second surface shown in FIG. 1 , the positive input terminal Vin+, the positive output terminal Vo+, the negative output terminal Vo-, and the signal terminal signal are all arranged in the port areas 110 and 210 in the form of gold fingers; Figure 6C In the figure, the output negative terminal Vo- and the output positive terminal Vo+ are arranged alternately, and the signal terminal signal, the input positive terminal Vin+, the output negative terminal Vo-, and the output positive terminal Vo+ are arranged from left to right along the x-axis direction; Fig.6D In the figure, the signal terminal signal, the output negative terminal Vo-, the output negative terminal Vo-, and the output positive terminal Vo+ are arranged from left to right along the x-axis direction, so that the power conversion device and the system mainboard (not shown) can be installed and fixedly connected by plugging and unplugging, which is convenient and quick. The gold finger corresponding to the signal terminal signal is located on the first side of the port area 110 and 210 close to the board edge. The output positive terminal Vo+ and the output negative terminal Vo- respectively include at least two gold fingers, and the gold fingers corresponding to the output positive terminal Vo+ and the output negative terminal Vo- are located on the second side of the port area 110 and 210 close to the board edge; the second side is opposite to the first side; the gold finger corresponding to the input positive terminal Vin+ is located in the port area 110, and is located between the gold finger corresponding to the signal terminal signal and the gold finger corresponding to the output positive terminal Vo+ or the output negative terminal Vo-.

[0100] The transformer core 20 includes two transformer magnetic substrates 21 and 22, transformer side columns 23 and 24, and a transformer center column 25. The transformer side columns 23 and 24 and the transformer center column 25 pass through the corresponding slots 73 and 74 and the hole 75, respectively, and are engaged with the two transformer magnetic substrates 21 and 22. On the circuit substrate 10, part or all of the circuit substrate between the slots 73 and the hole 75 and the slots 74 and the hole 75 is used to set the transformer windings W1, W21, and W22. Each end of the transformer windings W1, W21, and W22 is arranged adjacent to the switch areas 112 and 212, and the winding method of the transformer windings is not limited. Correspondingly, the middle switches Q2 / Q4 and the lower switches SR1 / SR2 arranged in the switch areas 112 and 212 are arranged adjacent to the transformer core area 113, and the middle switches Q2 / Q4 and the lower switches SR1 / SR2 are placed along the x-axis direction; further, the two lower switches SR1 / SR2 are arranged between the two middle switches Q2 / Q4. The projection of each middle switch Q2 arranged on the first surface 101 on the first surface partially overlaps or completely overlaps with the projection of the corresponding middle switch Q4 arranged on the second surface 102 on the first surface; similarly, the projection of each lower switch SR1 arranged on the first surface 101 on the first surface partially overlaps or completely overlaps with the projection of the corresponding lower switch SR2 arranged on the second surface 102 on the first surface. The upper switches Q1 and Q3 are arranged in the switch area 112 on the first surface 101, adjacent to the middle switches Q2 and Q4 respectively, and adjacent to the resonant capacitor Cr and the output capacitor Co respectively; the upper switches, the resonant capacitor Cr and the output capacitor Co are placed along the x-axis direction, and the resonant capacitor Cr and the output capacitor Co are located between the two upper switches. The projection of the output capacitor area 211 arranged on the second surface 102 on the first surface partially overlaps or completely overlaps with the output capacitor area 111 on the first surface 101; the projection of the resonant capacitor area 214 arranged on the second surface 102 on the first surface partially overlaps or completely overlaps with the resonant capacitor area 114 on the first surface 101; the projection of the input capacitor Cin arranged on the first surface 101 on the first surface partially overlaps or completely overlaps with the projection of the input capacitor Cin arranged on the second surface 102 on the first surface.

[0101] like Figure 3A The middle switch driving unit 42 is respectively arranged in the middle upper switch driving areas 121 and 122, and is respectively arranged adjacent to the middle switches Q2 and Q4; the upper switch driving unit 43 is respectively arranged in the middle upper switch driving areas 121 and 122, and is respectively arranged adjacent to the upper switches Q1 and Q3. The lower switch driving unit 41 and the driving magnetic member 44 are arranged in the lower switch driving areas 120 and 220. Figure 6C and Fig.6DAs shown, the circuit substrate 10 also includes a hole 71 and a slot 72, and the hole 71 and the slot 72 penetrate the lower switch driving area 120 of the first surface 101 and the lower switch driving area 220 of the second surface 102. The lower switch driving unit 41 also includes a driving magnetic core 80; the driving magnetic core 80 includes two driving magnetic substrates 81 and 82 and two driving side pillars 83 and 84, the hole 71 is surrounded by the circuit substrate on all sides, at least one side of the slot 72 is open, and the other sides are surrounded by the circuit substrate; the design of the slots 72 / 73 / 74 can minimize the surface area occupied by the circuit substrate 10 and reduce the volume of the power conversion device. In another embodiment, the slot 72 can also be designed as a hole like the hole 71. The driving side pillars 83 and 84 respectively pass through the corresponding holes 71 and slots 72, and are buckled with the two driving magnetic substrates 81 and 82. On the circuit substrate 10 , a portion of the circuit substrate between the hole 71 and the slot 72 is used to set the windings W31 and W41 to W44 of the driving magnetic member 44 , and the winding method of the windings W31 and W41 to W44 of the driving magnetic member 44 is not limited.

[0102] The circuit substrate 10 further includes a card slot 70, which passes through the first surface 101 and the second surface 102 of the circuit substrate, and the card slot 70 is arranged in the port areas 110 and 210. The system main board includes a protrusion (not shown) corresponding to the card slot 70. When the power conversion device is fixed to the system main board, the card slot 70 is engaged with the protrusion, which facilitates the assembly and installation of the power conversion device on the system main board, and further, can enhance the fixing strength of the power conversion device and the system main board.

[0103] The magnetic columns (side columns and middle columns) in the transformer core 20 or the driving core 80 disclosed in the present invention can be independently formed with two magnetic substrates, or the magnetic columns can be integrally formed with one of the magnetic substrates, or each magnetic column can be divided into two parts, each part is integrally formed with one magnetic substrate; the transformer core material and the driving core material can both be ferrite. The cross-section of the connection between the magnetic column of the transformer core 20 or the driving core 80 and the magnetic substrate and the cross-section of the magnetic substrate can be rectangular, square, circular or elliptical, etc., but are not limited thereto. The switch disclosed in the present invention can be SiMOSFET, SiCMOSFET, GaNMOSFET or IGBTMOSFET, etc., all of which can realize the function of the switch disclosed in the present invention.

[0104] The power conversion device described in the above embodiments may be a part of an electronic device or an independent power module, as long as it meets the technical features and benefits disclosed by the present invention.

[0105] The “equal”, “same” or “equal” disclosed in the present invention must take into account the parameter distribution of the project, and the error distribution is within ±30%; the definition of two line segments or two straight lines being “parallel” is that the angle between the two line segments or two straight lines is less than or equal to 45 degrees; the definition of two line segments or two straight lines being “perpendicular” is that the angle between the two line segments or two straight lines is within the range of [60, 120] degrees; the definition of phase “misalignment” also needs to take into account the parameter distribution of the project, and the error distribution of the misalignment degree is within ±30%.

[0106] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0107] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power conversion device, characterized in that: It includes a circuit substrate, a transformer assembly, a switch tube, an output capacitor, and an input positive terminal, an output positive terminal, and an output negative terminal; The circuit substrate comprises a first surface and a second surface opposite to each other, the first surface comprising a transformer area, a switch area, an output capacitor area and a port area; The transformer assembly is arranged in the transformer area, the switch tube is arranged in the switch area, at least a part of the output capacitor is arranged in the output capacitor area, and the input positive terminal, the output positive terminal and the output negative terminal are arranged in the port area; The transformer area, switch area, output capacitor area and port area are arranged in the same direction.

2. The power conversion device according to claim 1, characterized in that: The output positive terminal includes at least two output positive terminal gold fingers, and the output negative terminal includes at least two output negative terminal gold fingers. The output positive terminal gold fingers and the output negative terminal gold fingers are alternately arranged in the port area.

3. The power conversion device according to claim 1, characterized in that: The power conversion device further comprises a signal terminal, wherein the signal terminal comprises at least two signal terminal gold fingers, and the signal terminal gold fingers are arranged at one side of the port area.

4. The power conversion device according to claim 1, characterized in that: The switch tube includes two middle switches and two lower switches, wherein the two lower switches are arranged between the two middle switches, and the middle switch and the lower switch are arranged adjacent to the transformer area.

5. The power conversion device according to claim 4, characterized in that: The switch tube further includes two upper switches, and the two upper switches are respectively arranged adjacent to one of the middle switches.

6. The power conversion device according to claim 5, characterized in that: The power conversion device further includes a lower switch driving area and two middle and upper switch driving areas. The two middle and upper switch driving areas are respectively arranged on two opposite sides of the switch area and are arranged adjacent to the middle switch and / or the lower switch.

7. The power conversion device according to claim 6, characterized in that: The power conversion device also includes a drive unit, which includes a drive magnetic part, a lower switch drive unit, a middle switch drive unit and an upper switch drive unit. The drive magnetic part and the lower switch drive unit are arranged in the lower switch drive area, and the middle switch drive unit and the upper switch drive unit are arranged in the middle-upper switch drive area.

8. The power conversion device according to claim 2, characterized in that: The second surface includes a signal area and a port area, the output positive end gold finger and the output negative end gold finger are staggeredly arranged in the port area of ​​the second surface; the projection of at least one output positive end gold finger arranged on the second surface on the first surface at least partially overlaps with at least one corresponding output positive end gold finger arranged on the first surface; A projection of at least one negative output gold finger disposed on the second surface on the first surface at least partially overlaps with at least one corresponding negative output gold finger disposed on the first surface.

9. The power conversion device according to claim 4, characterized in that: The second surface includes a switch area, and the switch tube also includes two other middle switches and two other lower switches, and the other two middle switches and the other two lower switches are arranged in the switch area of ​​the second surface, and the projection of at least one middle switch or the lower switch arranged in the switch area of ​​the second surface on the first surface at least partially overlaps with the projection of the corresponding middle switch or the corresponding lower switch arranged on the first surface on the first surface.

10. The power conversion device according to claim 1, characterized in that: The second surface includes an output capacitor region, at least a portion of the output capacitor is arranged in the output capacitor region of the second surface, and the output capacitor arranged on the second surface is partially or entirely projected on the first surface within the output capacitor region of the first surface.

11. The power conversion device according to claim 9, characterized in that: The first surface and / or the second surface comprises a resonant capacitor region, and the resonant capacitor region is disposed adjacent to one of the middle switches or one of the upper switches.

12. A power conversion device, characterized in that: Including power conversion circuit, drive unit and control signal; The power conversion circuit comprises an input positive terminal, an input negative terminal, an output positive terminal and an output negative terminal, wherein the input negative terminal and the output negative terminal are short-circuited; the power conversion circuit comprises a three-switch bridge arm, wherein the three-switch bridge arm comprises a first upper switch, a first middle switch and a first lower switch electrically connected in series, wherein the first upper switch is electrically connected to the input positive terminal, wherein the first upper switch and the first middle switch are electrically connected to a first upper node, and wherein the first middle switch and the first lower switch are electrically connected to a first lower node; the power conversion circuit further comprises a second lower switch, wherein the first lower switch and the second lower switch are electrically connected to the input negative terminal; The control signal includes a first control signal, a second control signal, a third control signal and a fourth control signal; The driving unit includes a driving magnetic part, a lower switch driving unit, a middle switch driving unit and a lower switch driving unit, wherein the lower switch driving unit receives a first control signal, a second control signal, a third control signal and a fourth control signal, and outputs a lower switch driving signal to drive the two lower switches to be turned on and off, and the lower switch driving unit is electrically connected to the driving magnetic part; The middle switch driving unit receives the control signal by driving the magnetic member, and the middle switch driving unit outputs a middle switch driving signal to drive the two middle switches to be turned on and off; The upper switch driving unit receives the control signal by driving the magnetic member, and the upper switch driving unit outputs an upper switch driving signal to drive the two upper switches to be turned on and off.

13. The power conversion device according to claim 12, characterized in that: The lower switch driving unit includes a positive terminal of a driving power supply, a ground terminal, a first lower switch driving output terminal and a second lower switch driving output terminal. The lower switch driving unit also includes four control switches. The four control switches are electrically connected to form a full-bridge structure and are bridged between the positive terminal of the driving power supply and the ground terminal. The first lower switch driving output terminal and the second lower switch driving output terminal are respectively the midpoints of two bridge arms. The four control switches are respectively controlled by a first control signal, a second control signal, a third control signal and a fourth control signal.

14. The power conversion device according to claim 13, characterized in that: The driving magnetic part comprises a driving winding, a first middle winding and a first upper winding, wherein the driving winding, the first middle winding and the first upper winding are wound on the same magnetic core; the driving winding is bridged between the first lower switch driving output terminal and the second lower switch driving output terminal.

15. The power conversion device according to claim 14, characterized in that: The middle switch driving unit includes two middle driving switches, the drains of the two middle driving switches are electrically connected to the two ends of the first middle winding respectively, and the sources of the two middle driving switches are short-circuited to the first lower node; one end of the first middle winding and the first lower node constitute a first middle switch driving output end; the voltage between any end of the first middle winding and the first lower node is used to control the middle driving switch electrically connected to the other end of the first middle winding.

16. The power conversion device according to claim 14, characterized in that: The upper switch driving unit includes two upper driving switches, the drains of the two upper driving switches are electrically connected to the two ends of the first upper winding respectively, and the sources of the two upper driving switches are short-circuited to the first upper node; one end of the first upper winding and the first upper node constitute a first upper switch driving output end; the voltage between any end of the first upper winding and the first upper node is used to control the upper driving switch electrically connected to the other end of the first upper winding.

17. A power conversion device, characterized in that: It includes a power conversion circuit, a pre-charging unit, a sampling resistor and a sampling circuit unit; The power conversion circuit comprises an input positive terminal, an input negative terminal, an output positive terminal, an output negative terminal and an output capacitor, wherein the input negative terminal and the output negative terminal are short-circuited, and the output capacitor is connected across the output positive terminal and the output negative terminal; The sampling circuit unit is used to sample the working current of the power conversion circuit; The pre-charging unit comprises a switch end, an inductor end and a ground end, the switch end is electrically connected to the input positive end, the inductor end is electrically connected to the output positive end through the sampling resistor, and the ground end is electrically connected to the input negative end; the pre-charging unit pre-charges the output capacitor; The sampling resistor is used to sample the outflow current of the pre-charging unit.

18. The power conversion device according to claim 17, characterized in that: The power conversion circuit also includes two lower switches and two low-voltage windings; the first ends of the two low-voltage windings are electrically connected to the output positive end, and the second end of each low-voltage winding is electrically connected to one end of a lower switch and forms two lower nodes; the other end of the lower switch is electrically connected to the output negative end.

19. The power conversion device according to claim 18, characterized in that: The sampling circuit unit includes three sampling terminals, a reference terminal, a sampling output positive terminal and a sampling output negative terminal. Two of the three sampling terminals are electrically connected to a corresponding lower node, another sampling terminal of the three sampling terminals is electrically connected to the output positive terminal, and the reference terminal is electrically connected to the output positive terminal.

20. The power conversion device according to claim 19, characterized in that: The sampling circuit unit also includes three sampling resistors, a sampling capacitor, an impedance matching resistor and an amplifying unit; the first ends of the three sampling resistors are electrically connected to the midpoint of the sampling resistor, and the second end of each of the sampling resistors is electrically connected to a sampling end; the sampling capacitor and the impedance matching resistor are electrically connected in series between the reference end and the midpoint of the sampling resistor; the amplifying unit includes two input ends and two output ends, the two input ends are electrically connected to the two ends of the sampling capacitor, and the two output ends are electrically connected to the sampling output positive end and the sampling output negative end.

21. The power conversion device according to claim 17, characterized in that: The pre-charging unit also includes two pre-charging switches, a pre-charging inductor, a pre-charging capacitor and a pre-charging diode; the two pre-charging switches are electrically connected in series between the switch end and the ground end; one end of the pre-charging inductor is electrically connected to the series connection point of the two pre-charging switches, and the other end is electrically connected to the positive electrode of the pre-charging diode and the positive end of the output capacitor; the negative electrode of the pre-charging diode is electrically connected to the inductor end; and the negative end of the output capacitor is electrically connected to the ground end.

22. The power conversion device according to claim 17, characterized in that: When the terminal voltage across the output capacitor reaches a predetermined voltage, the pre-charging unit stops working; the predetermined voltage is greater than 70% of the output steady-state voltage Vo_normal of the power conversion circuit.

23. A power conversion device, characterized in that: It includes a power conversion circuit, a controller, a gating circuit, a current balancing circuit unit, an address circuit unit and a start control signal; The gating circuit includes two input terminals, a control terminal and an output terminal, the two input terminals are electrically connected to the current balancing circuit unit and the address circuit unit respectively, the output terminal is electrically connected to the controller, and the control terminal receives the start control signal; The controller is used to control the power conversion circuit; The start control signal controls the gating circuit, and the voltage of the current balancing circuit unit or the voltage of the address circuit unit is sent to the controller through the gating circuit.

24. The power conversion device according to claim 23, characterized in that: The power conversion device also includes a current source; When the start control signal is at a low level, the current source charges the address circuit unit, and the voltage of the address circuit unit is sent to the controller through the gating circuit; When the start control signal is at a high level, the current source charges the current balancing circuit unit, and the voltage of the current balancing circuit unit is sent to the controller through the gating circuit.

25. The power conversion device according to claim 23, characterized in that: The power conversion device includes a ground terminal; the current balancing circuit unit includes a current balancing resistor, a current balancing capacitor and a current balancing switch; the current balancing resistor and the current balancing capacitor are electrically connected in parallel between an input terminal of the selection circuit and the current balancing switch, one end of the current balancing switch is electrically connected to the ground terminal, and the other end of the current balancing switch is electrically connected to the current balancing resistor and the current balancing capacitor; the current balancing switch is controlled by the start control signal.

26. The power conversion device according to claim 23, characterized in that: The power conversion device includes a ground terminal; the address circuit unit includes an address resistor and an address capacitor, and the address resistor and the address capacitor are electrically connected in parallel between an input terminal of the gating circuit and the ground terminal.

27. A power conversion device, characterized in that: It includes a power conversion circuit, a dummy load unit, a power supply voltage and a dummy load control signal; The power conversion circuit comprises an input positive terminal, an input negative terminal, an output positive terminal and an output negative terminal, wherein the input negative terminal and the output negative terminal are short-circuited; The power conversion circuit further includes an input capacitor and an output capacitor, wherein the input capacitor is connected between the input positive terminal and the output positive terminal, and the output capacitor is connected between the output positive terminal and the output negative terminal; One end of the dummy load unit is electrically connected to the supply voltage, and the other end is electrically connected to the output positive terminal; The dummy load control signal controls the dummy load unit to discharge the output positive terminal.

28. The power conversion device according to claim 27, characterized in that: When the dummy load control signal is at a low level, the dummy load unit is switched into the power conversion device; when the dummy load control signal is at a high level, the dummy load unit is switched out of the power conversion device.

29. The power conversion device according to claim 28, characterized in that: The power conversion device also includes a starting control signal and a preset voltage; when the starting control signal of the power conversion device is at a high level, the dummy load control signal is at a high level; when the starting control signal of the power conversion device is at a low level and the output voltage of the power conversion device is greater than or equal to the preset voltage, the dummy load control signal is at a high level; when the starting control signal of the power conversion device is at a low level and the output voltage of the power conversion device is less than the preset voltage, the dummy load control signal is at a low level.

30. The power conversion device according to claim 27, characterized in that: The dummy load unit includes a power supply end, a ground end, a first dummy load control switch, a second dummy load control switch, a dummy load amplifying switch, a first current limiting resistor, a second current limiting resistor, a third current limiting resistor and a fourth current limiting resistor; the first current limiting resistor and the first dummy load control switch are connected in series between the power supply end and the ground end, and the gate of the first dummy load control switch is electrically connected to the dummy load control signal; the second current limiting resistor, the second dummy load control switch and the third current limiting resistor are connected in series between the power supply end and the ground end, and the gate of the second dummy load control switch is electrically connected to the drain of the first dummy load control switch; the dummy load amplifying switch and the fourth current limiting resistor are connected in series between the output positive end and the ground end of the power conversion device, and the base of the dummy load amplifying switch is electrically connected to the source of the second dummy load control switch.

31. The power conversion device according to claim 27, characterized in that: The dummy load unit includes a dummy load amplifying switch and a current limiting resistor, wherein the dummy load amplifying switch is electrically connected to the output positive terminal of the power conversion device; the dummy load control signal is used to control the on and off of the dummy load amplifying switch; and the current limiting resistor is used to control the current flowing through the dummy load amplifying switch.

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