Power conversion device and magnetic assembly

Abstract

The invention provides a circuit topology aiming at the application of high step-down ratio of input voltage to output voltage. The circuit topology has low switching loss and high conversion efficiency in a high-frequency switching occasion of a power switch. The invention further provides a power conversion device applying the circuit topology, a device layout setting of the power conversion device and a winding mode of a transformer are provided, the size of the power conversion device is reduced, and the steady-state performance and the dynamic performance of the power conversion device are improved.

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 and a magnetic component. Background Art

[0002] With the development of artificial intelligence, the power requirements of intelligent data processing chips, such as GPU / CPU / NPU, etc. (collectively referred to as xPU) are getting higher and higher, which has greatly increased the power of servers, and the input voltage of servers has gradually changed from 12V to 48V. However, the operating voltage of xPU is getting lower and lower with the advancement of technology, gradually moving from 0.8V to 0.65V. Therefore, the step-down ratio of input voltage to output voltage is getting higher and higher. In order to obtain a high conversion efficiency of 48V input to 0.65V output, a circuit architecture with high conversion efficiency is urgently needed.

[0003] The present invention provides a solution for a power conversion device with 48V input and 0.8V regulated output. The input ends of the primary half-bridge units are connected in series and the output ends are connected in parallel to reduce the input voltage of each half-bridge unit, thereby reducing the switching loss of the power switching device in each half-bridge unit under high-frequency switching, thereby improving the conversion efficiency of the overall power conversion device. Summary of the invention

[0004] In view of this, one of the purposes of the present invention is to provide a circuit topology suitable for applications with a high step-down ratio of input voltage to output voltage; the circuit topology has low switching loss and high conversion efficiency when the power switch is switched at a high frequency. The present invention also provides a power conversion device using the circuit topology, provides a device layout setting of the power conversion device and a winding method of the transformer, reduces the volume of the power conversion device, and improves the steady-state performance and dynamic performance of the conversion device.

[0005] In one aspect, the present invention provides a power conversion device, comprising a first half-bridge unit and a second half-bridge unit, wherein the first half-bridge unit and the second half-bridge unit each comprise at least two half-bridge switches, at least two half-bridge capacitors, at least two synchronous switches and a transformer; the transformer in each half-bridge unit constitutes a magnetic component; the magnetic component comprises a magnetic core, a primary winding and a secondary winding;

[0006] The power conversion device further includes a circuit substrate, the circuit substrate includes a first surface and a second surface opposite to each other, a plurality of winding post holes and a middle post hole, the winding post holes and the middle post holes penetrate the first surface and the second surface; the magnetic core includes a plurality of winding posts, a middle post and two magnetic substrates, the winding posts and the middle post respectively pass through the corresponding winding post holes and the middle post holes, the winding posts and the middle post and the two magnetic substrates buckle the circuit substrate; the magnetic core includes a first side edge and a third side edge opposite to each other, a second side edge and a fourth side edge opposite to each other, a first diagonal line and a second diagonal line;

[0007] The synchronous switch in the first half-bridge unit is arranged adjacent to the first side, the synchronous switch in the second half-bridge unit is arranged adjacent to the third side, and the synchronous switch in the first half-bridge unit and the synchronous switch in the second half-bridge unit are both arranged adjacent to the first diagonal line;

[0008] The half-bridge switch in the first half-bridge unit is arranged adjacent to the third side, the half-bridge switch in the second half-bridge unit is arranged adjacent to the first side, and the half-bridge switch in the first half-bridge unit and the half-bridge switch in the second half-bridge unit are both arranged adjacent to the second diagonal line.

[0009] Preferably, the half-bridge capacitor in the first half-bridge unit is arranged adjacent to the third side, the half-bridge capacitor in the second half-bridge unit is arranged adjacent to the first side, and the half-bridge capacitor in the first half-bridge unit and the half-bridge capacitor in the second half-bridge unit are both arranged adjacent to the second diagonal.

[0010] Preferably, the half-bridge capacitor and the half-bridge switch in the first half-bridge unit are respectively arranged on two opposite surfaces; the half-bridge capacitor and the half-bridge switch in the second half-bridge unit are respectively arranged on two opposite surfaces.

[0011] Preferably, the first half-bridge unit and the second half-bridge unit both include two synchronous switches, the synchronous switches of the first half-bridge unit are arranged on the first surface, and two of the synchronous switches of the second half-bridge unit are arranged on the second surface.

[0012] Preferably, a projection of a synchronization switch disposed on the first surface on the first surface at least partially overlaps with a projection of a corresponding synchronization switch disposed on the second surface on the first surface.

[0013] Preferably, the first half-bridge unit and the second half-bridge unit both further include an output negative terminal pin, the output negative terminal pin in the first half-bridge unit is arranged adjacent to the first side, the output negative terminal pin in the second half-bridge unit is arranged adjacent to the third side, and the output negative terminal pin in the first half-bridge unit and the output negative terminal pin in the second half-bridge unit are arranged adjacent to the first diagonal line.

[0014] Preferably, the output negative terminal pin in the first half-bridge unit is disposed adjacent to the synchronous switch in the first half-bridge unit, and / or the output negative terminal pin in the second half-bridge unit is disposed adjacent to the synchronous switch in the second half-bridge unit.

[0015] Preferably, the first half-bridge unit and the second half-bridge unit both further include an output positive pin, the output positive pin in the first half-bridge unit is arranged adjacent to the third side, the output positive pin in the second half-bridge unit is arranged adjacent to the first side, and the output positive pin in the first half-bridge unit and the output positive pin in the second half-bridge unit are arranged adjacent to the second diagonal.

[0016] Preferably, the magnetic component includes four primary windings and four secondary windings, the magnetic core includes four winding poles, the four primary windings are respectively wound on the four winding poles, and the four secondary windings are respectively wound on the four winding poles.

[0017] Preferably, the magnetic core is buckled into the circuit substrate, and the four winding posts are arranged around the middle post, and the four winding posts are respectively a first winding post, a second winding post, a third winding post and a fourth winding post, the first winding post is arranged adjacent to the first side and the second side, the second winding post is arranged adjacent to the second side and the third side, the third winding post is arranged adjacent to the first side and the fourth side, and the fourth winding post is arranged adjacent to the third side and the fourth side; the four primary windings are respectively a first primary winding, a second primary winding, a third primary winding and a fourth primary winding; the four secondary windings are respectively a first secondary winding, a second secondary winding, a third secondary winding and a fourth secondary winding; the second end of the first primary winding is electrically connected to the first end of the second primary winding, and the second end of the third primary winding is electrically connected to the first end of the fourth primary winding; the second end of the first secondary winding is electrically connected to the first end of the second secondary winding, and the second end of the third secondary winding is electrically connected to the first end of the fourth secondary winding.

[0018] Preferably, a first channel is provided between the first winding post and the third winding post, a second channel is provided between the first winding post and the second winding post, a third channel is provided between the second winding post and the fourth winding post, and a fourth channel is provided between the fourth winding post and the third winding post; the first primary winding is electrically connected in series with the second primary winding, and is wound in an 8-shape on the first winding post and the second winding post; the third primary winding is electrically connected in series with the fourth primary winding, and is wound in an 8-shape on the third winding post and the fourth winding post; the first secondary winding is electrically connected to the second secondary winding, and is wound in an 8-shape on the first winding post and the second winding post; the third secondary winding is electrically connected to the fourth secondary winding, and is wound in an 8-shape on the third winding post and the fourth winding post.

[0019] Preferably, the power conversion device further includes an output positive terminal pin; the first end of the first primary winding and the second end of the second primary winding are arranged adjacent to the third side, the first end of the first primary winding is electrically connected to the half-bridge switch in the same half-bridge unit, and the second end of the second primary winding is electrically connected to the half-bridge capacitor in the same half-bridge unit; the first end of the third primary winding and the second end of the fourth primary winding are arranged adjacent to the first side, the first end of the third primary winding is electrically connected to the half-bridge switch in the same half-bridge unit, and the second end of the fourth primary winding is electrically connected to the half-bridge capacitor in the same half-bridge unit; the first end of the first secondary winding is electrically connected to the half-bridge switch in the same half-bridge unit, and the second end of the fourth primary winding is electrically connected to the half-bridge capacitor in the same half-bridge unit; The first end of the first secondary winding, the second end of the second secondary winding, the second end of the third secondary winding and the first end of the fourth secondary winding are arranged adjacent to the first side, and the second end of the first secondary winding, the first end of the second secondary winding, the first end of the third secondary winding and the second end of the fourth secondary winding are arranged adjacent to the third side; the first end of the first secondary winding, the second end of the second secondary winding, the first end of the third secondary winding and the second end of the fourth secondary winding are electrically connected to a synchronous switch respectively, and the second end of the first secondary winding, the first end of the second secondary winding, the second end of the third secondary winding and the first end of the fourth secondary winding are electrically connected to the output positive terminal pin.

[0020] Another aspect of the present invention discloses a magnetic component, including a magnetic core, a primary winding, a first secondary winding, and a second secondary winding; the magnetic core includes a first side surface and a third side surface opposite to each other, a second side surface and a fourth side surface opposite to each other, a first winding post, a second winding post, and a middle post; the first winding post is disposed adjacent to the first side surface, the second winding post is disposed adjacent to the third side surface, and the middle post is disposed adjacent to the fourth side surface;

[0021] The first end and the second end of the primary winding are both arranged adjacent to the third side surface, the primary winding is wound around the first winding post and the second winding post from the first end to the second end, and the winding direction of the primary winding on the first winding post from the first end to the second end is opposite to the winding direction on the second winding post;

[0022] The second end of the first secondary winding and the first end of the second secondary winding are short-circuited, and the short-circuit point is arranged adjacent to the third side; the first end of the first secondary winding and the second end of the second secondary winding are both arranged adjacent to the first side; the secondary winding is wound around the first winding post and the second winding post in an "8" shape from the first end of the first secondary winding to the second end of the second secondary winding.

[0023] Preferably, the first end of the primary winding is arranged between the second winding pole and the fourth side surface, and the second end of the primary winding is arranged between the second winding pole and the second side surface.

[0024] Preferably, the first end of the first secondary winding is arranged between the first winding pole and the second side surface, and the second end of the second secondary winding is arranged between the first winding pole and the fourth side surface.

[0025] Preferably, the first end of the primary winding is electrically connected to the two switching elements.

[0026] Preferably, the second end of the primary winding is electrically connected to two capacitive elements.

[0027] Preferably, the first end of the first secondary winding and the second end of the second secondary winding are both electrically connected to a switching element.

[0028] Preferably, the short-circuit points of the first secondary winding and the second secondary winding are electrically connected to a capacitive element.

[0029] The beneficial effects of the present invention are:

[0030] (1) The circuit topology of the present invention is suitable for applications with a high step-down ratio of input voltage to output voltage; and the circuit topology has low switching loss and high conversion efficiency in the case of high-frequency switching of power switches; the present invention reduces the input voltage of each half-bridge unit by connecting the input ends of two half-bridge units in series and the output ends in parallel, thereby reducing the switching loss of the power switch device in each half-bridge unit and improving the conversion efficiency of each half-bridge unit and the entire power conversion circuit.

[0031] (2) The device layout and transformer winding method of the power conversion device of the present invention reduce the volume of the power conversion device and improve the steady-state performance and dynamic performance of the conversion device; the transformer winding method enables the power conversion device to output current from two opposite sides of the magnetic core, increases the routing area of ​​the power current, and reduces the parasitic resistance on the power current path, which is particularly suitable for occasions where the input voltage has a high step-down ratio to the output voltage and the output is low voltage and high current; BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 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.

[0033] Figure 1 is a schematic diagram of circuit topology 1;

[0034] Figure 2 is a schematic diagram of the three-dimensional structure of a power conversion device;

[0035] Figure 3a and Figure 3b This is a cross-sectional view of the transformer winding;

[0036] Figure 4a and Figure 4b It is a schematic diagram of the layout of the power conversion device;

[0037] Figure 5 Schematic diagram of power supply for the drive;

[0038] Figure 6 is a schematic diagram of circuit topology 2;

[0039] Figure 7a is a schematic diagram of circuit topology 3;

[0040] Figure 7b and Figure 7c A cross-sectional view of another transformer winding;

[0041] in:

[0042] 1 / 2 / 3 circuit topology; 1a / 1b half-bridge unit; 1-1 / 3-1 power conversion device; 10 circuit substrate; 20 magnetic core; 21 first winding column; 22 second winding column; 23 third winding column; 24 fourth winding column; 25 middle column; 26 magnetic substrate; 101 first surface; 102 second surface; 111 first hole; 112 second hole; 113 third hole; 114 fourth hole; 115 middle column hole;

[0043] 201 first side; 202 second side; 203 third side; 204 fourth side; 211 first channel; 212 second channel; 213 third channel; 214 fourth channel; C1 / C2 / C3 / C4 half-bridge capacitor; C11 / C12 / C13 / C14 power supply capacitor; Co output capacitor; Dr1 / Dr2 / Dr3 / Dr4 drive unit; D1 / D2 drive diode; D4 / D5 voltage regulator diode; R1 / R2 drive resistor; Q1 / Q2 / Q3 / Q4 half-bridge switch; SR1 / SR2 / SR3 / SR4 synchronous switch; SWH / SWL / VCAPH / VCAPL series midpoint; VDD supply voltage; VDD1 / VDD2 / VDD3 / VDD4 electrical network; VM connection point; Vin+ input positive terminal; Vin- input negative terminal; Vo+ output positive terminal; Vo- output negative terminal; W11 / W12 / W31 / W32 primary winding; W21 / W22 / W41 / W42 secondary winding. DETAILED DESCRIPTION

[0044] One of the cores of the present invention is to provide a circuit topology suitable for applications with a high step-down ratio of input voltage to output voltage; the circuit topology has low switching loss and high conversion efficiency when the power switch is switched at a high frequency. Another core of the present invention is to provide a power conversion device, provide a device layout setting of the power conversion device and a winding method of the transformer, reduce the volume of the power conversion device, and improve the steady-state performance and dynamic performance of the conversion device.

[0045] 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.

[0046] The present invention adopts the method of connecting the input ends of two half-bridge circuits in series and the output ends in parallel. Figure 1As shown in the circuit schematic diagram, the circuit topology 1 includes two half-bridge units 1a and 1b, the input ends of the two half-bridge units 1a and 1b are connected in series, and the output ends are connected in parallel. The half-bridge unit 1a includes two half-bridge switches Q1 and Q2, two half-bridge capacitors C1 and C2, a transformer, two synchronous switches SR1 and SR2, and an output capacitor Co; wherein the source of the half-bridge switch Q1 and the drain of Q2 are electrically connected to the series midpoint SWH, the second end of the half-bridge capacitor C1 and the first end of C2 are electrically connected to the series midpoint VCAPH, the drain of the half-bridge switch Q1 and the first end of the half-bridge capacitor C1 are electrically connected to the input positive terminal Vin+, and the source of the half-bridge switch Q2 and the second end of the half-bridge capacitor C2 are electrically connected to the series point VM. The transformer includes two primary windings W11 and W12, and two secondary windings W21 and W22. The second end of the primary winding W11 is electrically connected to the first end of W12, the first end of the primary winding W11 is electrically connected to the series midpoint SWH, and the second end of the primary winding W12 is electrically connected to the series midpoint VCAPH; the second end of the secondary winding W21 and the first end of W22 are electrically connected to the output positive terminal Vo+, the first end of the secondary winding W21 is electrically connected to the drain of the synchronous switch SR2, and the second end of the secondary winding W22 is electrically connected to the drain of the synchronous switch SR1. The primary winding W11 and the secondary winding W21 are wound on the same winding pole, and the first end of the primary winding W11 and the second end of the secondary winding W21 are the same-named ends, marked as point ends; the primary winding W12 and the secondary winding W22 are wound on the same winding pole, and the first end of the primary winding W21 and the second end of the secondary winding W22 are the same-named ends, marked as point ends; the sources of the two synchronous switches SR1 and SR2 are electrically connected to the output negative terminal Vo-. The output capacitor Co is connected between the output positive terminal Vo+ and the output negative terminal Vo-.The half-bridge unit 1b includes two half-bridge switches Q3 and Q4, two half-bridge capacitors C3 and C4, a transformer, two synchronous switches SR3 and SR4, and an output capacitor Co; the structure of the half-bridge unit 1b is basically the same as that of 1a, except that the source of the half-bridge switch Q3 and the drain of Q4 are electrically connected to the series midpoint SWL, the second end of the half-bridge capacitor C3 and the first end of C4 are electrically connected to the series midpoint VCAPL, the drain of the half-bridge switch Q3 and the first end of the half-bridge capacitor C3 are electrically connected to the series point VM, and the source of the half-bridge switch Q4 and the second end of the half-bridge capacitor C4 are electrically connected to the input negative terminal Vin-; the transformer includes The connection method and the positions of the same-named ends of the primary windings W31 and W32 and the secondary windings W41 and W42 are similar to the transformer connection method in the half-bridge unit 1a; specifically, the second end of the primary winding W31 is electrically connected to the first end of W32, the first end of the primary winding W31 is electrically connected to the series midpoint SWL, and the second end of the primary winding W32 is electrically connected to the series midpoint VCAPL; the second end of the secondary winding W41 and the first end of W42 are electrically connected to the output positive terminal Vo+, the first end of the secondary winding W41 is electrically connected to the drain of the synchronous switch SR4, and the second end of the secondary winding W22 is electrically connected to the drain of the synchronous switch SR3. The primary winding W31 and the secondary winding W41 are wound on the same winding pole, and the first end of the primary winding W31 and the second end of the secondary winding W41 are the same end, marked as a point end; the primary winding W32 and the secondary winding W42 are wound on the same winding pole, and the first end of the primary winding W32 and the second end of the secondary winding W42 are the same end, marked as a point end; the sources of the two synchronous switches SR3 and SR4 are electrically connected to the output negative terminal Vo-. The output capacitor Co is connected across the output positive terminal Vo+ and the output negative terminal Vo-. Further, the primary winding W11, the primary winding W12, the primary winding W31 and the primary winding W32 are respectively wound on four different winding poles.

[0047] In the present invention, the input voltage of each half-bridge unit is reduced by connecting the input ends of two half-bridge units in series and the output ends in parallel, thereby reducing the switching loss of the power switch device in each half-bridge unit, and improving the conversion efficiency of each half-bridge unit and the entire power conversion circuit. In the half-bridge units 1a and 1b of the present invention, the PWM drive signal switching frequency of the half-bridge switches at corresponding positions is the same, the duty cycle is the same, and the phase is staggered by 90 degrees; and because the PWM drive signal switching frequency of the upper switch and the lower switch of each half-bridge unit is the same, the duty cycle is the same, and the phase is staggered by 180 degrees, the PWM drive signals of the half-bridge switch Q1, the half-bridge switch Q2, the half-bridge switch Q3, and the half-bridge switch Q4 are staggered by 90 degrees in sequence; the advantage of this is that the frequency of the pulse current at the input end is 4 times the switching frequency of each half-bridge switch, which helps to significantly reduce the size of the input filter. In addition, the PWM drive signal of the synchronous switch SR1 is complementary to the PWM drive signal of the half-bridge switch Q1; the PWM drive signal of the synchronous switch SR2 is complementary to the PWM drive signal of the half-bridge switch Q2; the PWM drive signal of the synchronous switch SR3 is complementary to the PWM drive signal of the half-bridge switch Q3; and the PWM drive signal of the synchronous switch SR4 is complementary to the PWM drive signal of the half-bridge switch Q4.

[0048] The present invention also discloses a power conversion device 1-1, which is used as Figure 1 The circuit diagram is shown in FIG. 1 , and the three-dimensional structure diagram of the power conversion device 1-1 is shown in FIG. Figure 2 As shown, the circuit board 10, the magnetic core 20, a plurality of switches and a plurality of capacitors are included. The magnetic core 20 includes two magnetic substrates 26, a first winding post 21, a second winding post 22, a third winding post 23, a fourth winding post 24 and a middle post 25.

[0049] The circuit substrate 10 includes a first surface 101, a second surface 102, a first hole 111, a second hole 112, a third hole 113, a fourth hole 114 and a center column hole 115, and the first surface 101 and the second surface 102 are opposite to each other; the first hole 111, the second hole 112, the third hole 113, the fourth hole 114 and the center column hole 115 penetrate the first surface 101 and the second surface 102 respectively, and are respectively provided for the first winding post 21, the second winding post 22, the third winding post 23, the fourth winding post 24 and the center column 25 to pass through, and the two magnetic substrates 26 are respectively attached to the first surface 101 and the second surface 102. After the magnetic core 20 is buckled with the circuit substrate 10, a circuit diagram is formed with the winding arranged in the circuit substrate as shown in FIG. Figure 1In this embodiment, the first hole 111, the second hole 112, the third hole 113 and the fourth hole 114 are respectively arranged around the hole of the middle column. After the magnetic core 20 is buckled with the circuit substrate, the middle column 25 is correspondingly surrounded by the first winding column 21, the second winding column 22, the third winding column 23 and the fourth winding column 24. A plurality of switches and a plurality of capacitors are respectively arranged on the first surface 101 and the second surface 102.

[0050] The present invention also discloses a method for winding a transformer used in the power conversion device 1-1, such as Figure 3a and 3b The cross-sectional view shown, Figure 3a The winding method of the primary windings W11, W12, W31 and W32 is as follows: Figure 3b The figure shows the winding method of the secondary windings W21, W22, W41 and W42. Figure 3a As shown, the magnetic core 20 includes a first side 201 and a third side 203 opposite to each other, and a second side 202 and a fourth side 204 opposite to each other. A first channel 211 is provided between the first winding post 21 and the third winding post 23, and the first channel 211 is adjacent to the first side 201; a second channel 212 is provided between the first winding post 21 and the second winding post 22, and the second channel 212 is adjacent to the second side 202; a third channel 213 is provided between the second winding post 22 and the fourth winding post 24, and the third channel 213 is adjacent to the third side 203; a fourth channel 214 is provided between the fourth winding post 24 and the third winding post 23, and the fourth channel 214 is adjacent to the fourth side 204.

[0051] like Figure 3aAs shown, after the primary windings W11 and W12 are electrically connected in series, they are wound in an "8" shape on the first winding post 21 and the second winding post 22. After the primary windings W31 and W32 are electrically connected in series, they are wound in an "8" shape on the third winding post 23 and the fourth winding post 24. In detail, the first end of the primary winding W11 (i.e., the series midpoint SWH) and the second end of the primary winding W12 (i.e., the series midpoint VCAPH) are arranged adjacent to the third side 203 of the magnetic core 20. From SWH to VCAPH, the primary winding first passes through the third passage 213, winds at least one turn around the second winding post 22 in a counterclockwise direction (i.e., the first direction), then passes through the second channel 212 and the first channel 211, winds at least one turn around the first winding post 21 in a clockwise direction (i.e., the second direction), and then returns to the third side 203. The first end (i.e., SWL) of the primary winding W31 and the second end (i.e., VCAPL) of the primary winding W32 are arranged adjacent to the first side 201 of the magnetic core 20. From SWL to VCAPL, the primary winding first goes along the fourth side, then passes through the fourth channel 214, and is wound counterclockwise around the fourth winding post 24 for at least one turn, then passes through the fourth channel 214 and the first channel 211, and is wound clockwise around the third winding post 23 for at least one turn, and returns to the first side 201. This embodiment is described by taking the example that the primary winding is wound around each winding post for 2 turns, which is not limited to the order here. In some other embodiments, the primary winding can also be wound around each winding post for 1 turn or more turns, and those skilled in the art can select the corresponding number of turns according to actual needs.

[0052] like Figure 3bAs shown, after the secondary windings W21 and W22 are electrically connected in series, they are wound on the first winding post 21 and the second winding post 22 in an "8" shape; after the secondary windings W41 and W42 are electrically connected in series, they are wound on the third winding post 23 and the fourth winding post 24 in an "8" shape. In detail, the first end of the secondary winding W21 and the second end of W22 are arranged adjacent to the first side 201 of the magnetic core 20; the second end of the secondary winding W21 and the first end of W22 are short-circuited (i.e., the output positive end Vo+) and are arranged adjacent to the third side 203 of the magnetic core 20; the secondary winding W21 is first wound along the second side from the first end to the second end, and then passes through the second channel 212 and then passes through the third channel 213; the secondary winding W22 is first wound along the second side from the first end to the second end, and then passes through the second channel 212 and then passes through the first channel 211. The first end of the secondary winding W41 and the second end of W42 are arranged adjacent to the third side 203 of the magnetic core 20, and the second end of the secondary winding W41 and the first end of W41 are short-circuited (i.e., the output positive end Vo+) and arranged adjacent to the first side 201 of the magnetic core 20; the secondary winding W41 first passes through the third channel 213 from the first end to the second end, then passes through the fourth channel 214, and then is wound along the fourth side 204; the secondary winding W42 first passes through the first channel 211 from the first end to the second end, then passes through the fourth channel 214, and then is wound along the fourth side 204. The magnetic core 20, the four primary windings W11 / W12 / W31 / W32 and the four secondary windings W21 / W22 / W41 / W42 constitute a magnetic component.

[0053] In the present invention, the connection end of the secondary winding of the first half-bridge unit 1a and the synchronous switch, and the connection end of the secondary winding of the second half-bridge unit 1b and the synchronous switch are respectively arranged on the first side 201 and the third side 203 of the magnetic core 20, and are respectively adjacent to the first winding post 21 and the fourth winding post 24; so that the connection end of the secondary winding of the first half-bridge unit 1a and the synchronous switch, and the connection end of the secondary winding of the second half-bridge unit 1b and the synchronous switch are arranged adjacent to the first diagonal of the magnetic core 20 (the first diagonal passes through the first winding post 21, the middle post 25 and the fourth winding post 24). The connection end of the primary winding of the first half-bridge unit 1a and the half-bridge switch, and the connection end of the primary winding of the second half-bridge unit 1b and the half-bridge switch are respectively arranged on the third side 203 and the first side 201 of the magnetic core 20, and are respectively adjacent to the second winding column 22 and the third winding column 23; so that the connection end of the primary winding of the first half-bridge unit 1a and the half-bridge switch, and the connection end of the primary winding of the second half-bridge unit 1b and the half-bridge switch are arranged adjacent to the second diagonal of the magnetic core 20 (the second diagonal passes through the second winding column 22, the middle column 25 and the third winding column 23). The first diagonal and the second diagonal of the magnetic core 20 are nearly perpendicular to each other. This method of winding the transformer winding allows the power conversion device to output current from two opposite sides of the magnetic core, increases the routing area of ​​the power current, and reduces the parasitic resistance on the power current path. It is particularly suitable for occasions where the input voltage has a high step-down ratio to the output voltage, and the output is low voltage and large current.

[0054] Combination Figure 4a In the schematic diagram of the device layout on the first surface 101 shown, the synchronous switches SR1 and SR2 are arranged adjacent to the first side 201 of the magnetic core 20, that is, they are arranged adjacent to the second end of the secondary winding W22 and the first end of W21, respectively, so that the loop path surrounded by the synchronous switch SR1, the secondary winding W22, the secondary winding W21 and the synchronous switch SR2 is the shortest, the parasitic parameters on the loop are reduced, and the conversion efficiency of the power conversion device is improved. Similarly, the synchronous switches SR3 and SR4 are arranged adjacent to the third side 203 of the magnetic core 20, that is, they are arranged adjacent to the second end of the secondary winding W42 and the first end of the secondary winding W41, respectively, so that the loop path surrounded by the synchronous switch SR3, the secondary winding W42, the secondary winding W41 and the synchronous switch SR4 is the shortest, the parasitic parameters on the loop are reduced, and the conversion efficiency of the power conversion device is improved. Here, the synchronous switch of the first half-bridge unit and the synchronous switch of the second half-bridge unit are respectively arranged on the first side 201 and the third side 203 of the magnetic core 20, and are respectively adjacent to the first winding column 21 and the fourth winding column 24; so that the synchronous switch of the first half-bridge unit and the synchronous switch of the second half-bridge unit are arranged adjacent to the first diagonal of the magnetic core 20.

[0055] Reference Figure 3a and Figure 4aAs shown, the half-bridge switches Q1 and Q2 are arranged adjacent to the third side 203 of the magnetic core 20, that is, the half-bridge switches Q1 and Q2 are arranged adjacent to the first end of the primary winding W11; the half-bridge switches Q3 and Q4 are arranged adjacent to the first side 201 of the magnetic core 20, that is, the half-bridge switches Q3 and Q4 are arranged adjacent to the first end of the primary winding W31. Here, the half-bridge switch of the first half-bridge unit and the half-bridge switch of the second half-bridge unit are respectively arranged on the third side 203 and the first side 201 of the magnetic core 20, and are respectively adjacent to the second winding post 22 and the third winding post 23; so that the half-bridge switch of the first half-bridge unit and the half-bridge switch of the second half-bridge unit are arranged adjacent to the second diagonal of the magnetic core 20.

[0056] Also refer to Figure 4b The schematic diagram of the device layout on the second surface 102 shown, the half-bridge capacitors C1, C2, C3 and C4, the output positive terminal Vo+ pin, and the output negative terminal Vo- pin of the first half-bridge unit and the second half-bridge unit. The synchronous switches SR1 and SR2 of the first half-bridge unit arranged on the second surface 102 are respectively connected in parallel with the synchronous switches SR1 and SR2 of the first half-bridge unit on the first surface 101; and the projections of the synchronous switches SR1 respectively arranged on the first surface 101 and the second surface 102 on the first surface 101 at least partially overlap, and the projections of the synchronous switches SR2 respectively arranged on the first surface 101 and the second surface 102 on the first surface 101 at least partially overlap. Similarly, the synchronous switches SR3 and SR4 of the second half-bridge unit on the second surface 102 are respectively connected in parallel with the synchronous switches SR3 and SR4 of the second half-bridge unit on the first surface 101; and the projections of the synchronous switches SR3 respectively arranged on the first surface 101 and the second surface 102 on the first surface 101 at least partially overlap, and the projections of the synchronous switches SR4 respectively arranged on the first surface 101 and the second surface 102 on the first surface 101 at least partially overlap. The half-bridge capacitors C1 and C2 are arranged adjacent to the third side 203 of the magnetic core 20, and are located adjacent to the projections of the half-bridge switches Q1 and Q2 on the horizontal plane, thereby reducing the loop area formed by the half-bridge switch, the primary winding, and the half-bridge capacitor, thereby further reducing the loop parasitic parameters and improving the conversion efficiency. The half-bridge capacitors C3 and C4 are arranged adjacent to the first side 201 of the magnetic core 20, and are located adjacent to the projections of the half-bridge switches Q3 and Q4 on the horizontal plane, thereby reducing the loop formed by the half-bridge switch, the primary winding, and the half-bridge capacitor. The two positive output terminals Vo+ pins are respectively adjacent to the first side 201 and the third side 203 of the magnetic core 20 , and are respectively adjacent to the second winding post 22 and the third winding post 23 , that is, they are respectively disposed adjacent to the second diagonal line of the magnetic core 20 .

[0057] The two output negative terminal Vo- pins are respectively arranged on opposite sides of the magnetic core 20, adjacent to the first diagonal line; further, the two output negative terminal Vo- pins are respectively arranged on the outside of the first half-bridge unit synchronous switch and the second half-bridge unit synchronous switch, and are respectively placed adjacent to the source of the corresponding synchronous switch. The two output positive terminal Vo+ pins are respectively arranged on opposite sides of the magnetic core 20, adjacent to the second diagonal line.

[0058] In the present invention, the synchronous switch of the first half-bridge unit and the synchronous switch of the second half-bridge unit are respectively arranged on the first side 201 and the third side 203 of the magnetic core 20, and are arranged adjacent to the first diagonal line; and the output positive terminal pins are respectively arranged on the first side 201 and the third side 203 of the magnetic core 20, and are arranged adjacent to the second diagonal line; so that the power conversion device can output current from the two sides of the magnetic core, increase the routing area of ​​the power current, and reduce the parasitic resistance on the power current path, which is particularly suitable for the occasions with a high step-down ratio of input voltage to output voltage and low voltage and large current output. In addition, because the output positive terminal Vo+ pin is respectively adjacent to the second winding column 22 and the third winding column 23, and the output negative terminal Vo- pin is respectively adjacent to the source of the synchronous switch, the routing distance connecting the output positive terminal Vo+ pin or the output negative terminal Vo- pin on the power current path is the shortest, and the parasitic resistance is the smallest.

[0059] The winding method disclosed in the present invention allows the DC magnetic flux flowing through each winding pole to be added on the middle pole, and the AC magnetic flux flowing through each winding pole to be superimposed on the middle pole in phase; and because the two half-bridge units 1a and 1b are staggered in phase, the voltage waveforms of the windings on the four winding poles are staggered by 90 degrees, that is, the AC magnetic flux waveforms of the four winding poles are staggered by 90 degrees, so that the circuit topology has the advantages of small output dynamic inductance and large output steady-state inductance. The volume of the magnetic core can be reduced, and the steady-state characteristics and dynamic conversion characteristics of the power conversion device can be improved.

[0060] The present invention also discloses a driving power supply method after the half-bridge units are connected in series, such as Figure 5As shown, the power conversion device also includes four drive units Dr1, Dr2, Dr3 and Dr4, which provide drive signals for half-bridge switches Q1, Q2, Q3 and Q4 respectively; the four drive units each include a driver and a power supply capacitor (i.e., power supply capacitors Cl1, Cl2, Cl3 and Cl4 in the figure). Among them, the drive units Dr1, Dr2 and Dr3 each also include a power supply diode (i.e., power supply diodes D1, D2 and D3 in the figure), and the drive units Dr2 and Dr3 each also include a power supply resistor and a voltage regulator tube (i.e., power supply resistors R1 and R2, voltage regulator tubes D4 and D5 in the figure). The power supply voltage of the drive unit Dr4 is VDD, that is, the voltage of the power supply capacitor Cl1 between the electrical network VDD1 and the negative input terminal Vin- is the power supply voltage VDD. In the driving unit Dr3, the positive electrode of the power supply diode D1 is electrically connected to the electrical network VDD1, and the negative electrode of the power supply diode D1 is electrically connected to the electrical network VDD2; one end of the power supply resistor R1 is electrically connected to the electrical network VDD1, and the other end of the power supply resistor R1 is electrically connected to the series connection point VM; the voltage stabilizing diode D4 is connected in parallel with the power supply capacitor Cl2, and is connected between the electrical network VDD2 and the series connection midpoint SWL. When the half-bridge switch Q4 is turned on, the series connection midpoint SWL short-circuits the input negative terminal Vin-, and the power supply capacitor C11 is connected in parallel with the power supply capacitor C12 via the power supply diode D1, and the voltage across the power supply capacitor C12 is equal to the power supply voltage VDD (ignoring the conduction voltage drop of the driving diode D1), and the power supply capacitor C12 provides power for the driving unit Dr3. In the driving unit Dr2, the positive electrode of the power supply diode D2 is electrically connected to the electrical network VDD2, and the negative electrode of the power supply diode D2 is electrically connected to the electrical network VDD3; one end of the power supply resistor R2 is electrically connected to the electrical network VDD2, and the other end of the power supply resistor R2 is electrically connected to the input positive terminal Vin+; the voltage stabilizing diode D5 is connected in parallel with the power supply capacitor Cl3 and is connected across the electrical network VDD3 and the series connection point VM. When the half-bridge switch Q3 is turned on, the series connection point VM is short-circuited with the series connection midpoint SWL, and the power supply capacitor C12 is connected in parallel with the power supply capacitor C13 via the power supply diode D2, and the voltage across the power supply capacitor C13 is equal to the power supply voltage VDD (ignoring the conduction voltage drop of the driving diode D2), and the power supply capacitor C13 provides power for the driving unit Dr2. In the driving unit Dr1, the positive electrode of the power supply diode D3 is electrically connected to the electrical network VDD3, the negative electrode of the power supply diode D3 is electrically connected to the electrical network VDD4, and the power supply capacitor Cl4 is connected across the electrical network VDD4 and the series connection midpoint SWH. When the half-bridge switch Q2 is turned on, the series midpoint SWH and the series point VM are short-circuited, the power supply capacitor C13 is connected in parallel with the power supply capacitor C14 via the power supply diode D3, and the voltage across the power supply capacitor C14 is equal to the power supply voltage VDD (ignoring the conduction voltage drop of the driving diode D3), and the power supply capacitor C14 provides power for the driving unit Dr1.At the moment of starting the power conversion device, when the voltage VDD3 across the power supply capacitor Cl3 has not been established, the positive input terminal Vin+ is used to pre-charge the power supply capacitor C13 via the power supply resistor R2; so that at the moment of starting the power conversion device, the drive units Dr1 and Dr2 can output normal PWM signals. Similarly, the power supply resistor R1 and the power supply resistor R2 have similar functions; the voltage at the series point VM (i.e., Vin / 2) is used to pre-charge the power supply capacitor C12 via the power supply resistor R1, so that at the moment of starting the power conversion device, the pre-charge energy of the power supply capacitor C12 can be supplied to the power supply capacitor Cl3. The drive power supply circuit disclosed in the present invention can realize the drive power supply of four half-bridge switches in series, and the circuit is simple and easy to implement.

[0061] The device layout and transformer winding method disclosed in the present invention are also applicable to Figure 6 The circuit topology 2 shown in the figure also includes two half-bridge units 1a and 1b. The difference from the circuit topology 1 is that the input ends of the two half-bridge units 1a and 1b are connected in parallel, and the output ends are also connected in parallel. The power conversion device using the circuit topology 2 can be used as follows Figure 2 , Figure 3a , Figure 3b , Figure 4a and Figure 4b The same transformer winding method and device layout can also achieve the same benefits, which will not be repeated here.

[0062] In some other embodiments, the following may also be applied: Figure 7a The circuit topology 3 shown in FIG. 3 includes only one half-bridge unit 1a. The magnetic core used in the corresponding power conversion device 3-1 is as follows: Figure 7b As shown, the magnetic core 20a includes a first winding post 21, a second winding post 22 and a middle post 25, and also includes a first side 201, a second side 202, a third side 203 and a fourth side 204; wherein the first side 201 and the third side 203 are opposite to each other, and the second side 202 and the fourth side 204 are opposite to each other; wherein the middle post 25 is arranged adjacent to the fourth side 204, and a first channel 211 is formed between the middle post 25 and the first winding post 21, and the first channel 211 is adjacent to the first side 201; a second channel 212 is formed between the first winding post 21 and the second winding post 22, and the second channel 212 is adjacent to the second side 202; a third channel 213 is formed between the second winding post 22 and the middle post 25, and the third channel 213 is adjacent to the third side 203. The winding methods of the primary windings W11 and W12, and the secondary windings W21 and W22 can refer to Figure 7b and Figure 7c , this winding method is similar to Figure 3a and Figure 3bThe winding method shown is similar; the layout of the half-bridge switches Q1 and Q2, the synchronous switches SR1 and SR2, the half-bridge capacitors C1 and C2, and the output positive terminal Vo+ pin and the output negative terminal Vo- pin are similar Figure 4a and Figure 4b As shown, the features and benefits described in the above embodiments can all be obtained and will not be described in detail here.

[0063] The magnetic columns (side columns and middle columns) in the transformer core or inductor core 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 or inductor core 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.

[0064] 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.

[0065] 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.

[0066] 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%.

[0067] 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.

[0068] 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: The invention comprises a first half-bridge unit and a second half-bridge unit, wherein the first half-bridge unit and the second half-bridge unit each comprise at least two half-bridge switches, at least two half-bridge capacitors, at least two synchronous switches and a transformer; the transformer in each half-bridge unit constitutes a magnetic component; the magnetic component comprises a magnetic core, a primary winding and a secondary winding; The power conversion device further includes a circuit substrate, the circuit substrate includes a first surface and a second surface opposite to each other, a plurality of winding post holes and a middle post hole, the winding post holes and the middle post holes penetrate the first surface and the second surface; the magnetic core includes a plurality of winding posts, a middle post and two magnetic substrates, the winding posts and the middle post respectively pass through the corresponding winding post holes and the middle post holes, the winding posts and the middle post and the two magnetic substrates buckle the circuit substrate; the magnetic core includes a first side edge and a third side edge opposite to each other, a second side edge and a fourth side edge opposite to each other, a first diagonal line and a second diagonal line; The synchronous switch in the first half-bridge unit is arranged adjacent to the first side, the synchronous switch in the second half-bridge unit is arranged adjacent to the third side, and the synchronous switch in the first half-bridge unit and the synchronous switch in the second half-bridge unit are both arranged adjacent to the first diagonal line; The half-bridge switch in the first half-bridge unit is arranged adjacent to the third side, the half-bridge switch in the second half-bridge unit is arranged adjacent to the first side, and the half-bridge switch in the first half-bridge unit and the half-bridge switch in the second half-bridge unit are both arranged adjacent to the second diagonal line.

2. The power conversion device according to claim 1, characterized in that: The half-bridge capacitor in the first half-bridge unit is arranged adjacent to the third side, the half-bridge capacitor in the second half-bridge unit is arranged adjacent to the first side, and the half-bridge capacitor in the first half-bridge unit and the half-bridge capacitor in the second half-bridge unit are both arranged adjacent to the second diagonal line.

3. The power conversion device according to claim 2, characterized in that: The half-bridge capacitor and the half-bridge switch in the first half-bridge unit are respectively arranged on two opposite surfaces; the half-bridge capacitor and the half-bridge switch in the second half-bridge unit are respectively arranged on two opposite surfaces.

4. The power conversion device according to claim 1, characterized in that: The first half-bridge unit and the second half-bridge unit both include two synchronous switches. The synchronous switches of the first half-bridge unit are arranged on the first surface, and two of the synchronous switches of the second half-bridge unit are arranged on the second surface.

5. The power conversion device according to claim 4, characterized in that: The projection of the synchronization switch disposed on the first surface on the first surface at least partially overlaps with the projection of the corresponding synchronization switch disposed on the second surface on the first surface.

6. The power conversion device according to claim 1, characterized in that: The first half-bridge unit and the second half-bridge unit both include an output negative terminal pin, the output negative terminal pin in the first half-bridge unit is arranged adjacent to the first side, the output negative terminal pin in the second half-bridge unit is arranged adjacent to the third side, and the output negative terminal pin in the first half-bridge unit and the output negative terminal pin in the second half-bridge unit are arranged adjacent to the first diagonal line.

7. The power conversion device according to claim 6, characterized in that: The output negative terminal pin in the first half-bridge unit is disposed adjacent to the synchronous switch in the first half-bridge unit, and / or the output negative terminal pin in the second half-bridge unit is disposed adjacent to the synchronous switch in the second half-bridge unit.

8. The power conversion device according to claim 1, characterized in that: The first half-bridge unit and the second half-bridge unit both include an output positive pin, the output positive pin in the first half-bridge unit is arranged adjacent to the third side, the output positive pin in the second half-bridge unit is arranged adjacent to the first side, and the output positive pin in the first half-bridge unit and the output positive pin in the second half-bridge unit are arranged adjacent to the second diagonal.

9. The power conversion device according to claim 1, characterized in that: The magnetic component includes four primary windings and four secondary windings, the magnetic core includes four winding poles, the four primary windings are respectively wound on the four winding poles, and the four secondary windings are respectively wound on the four winding poles.

10. The power conversion device according to claim 9, characterized in that: The magnetic core is buckled into the circuit substrate, and the four winding posts are arranged around the middle post, and the four winding posts are respectively a first winding post, a second winding post, a third winding post and a fourth winding post, the first winding post is arranged adjacent to the first side and the second side, the second winding post is arranged adjacent to the second side and the third side, the third winding post is arranged adjacent to the first side and the fourth side, and the fourth winding post is arranged adjacent to the third side and the fourth side; the four primary windings are respectively a first primary winding, a second primary winding, a third primary winding and a fourth primary winding; the four secondary windings are respectively a first secondary winding, a second secondary winding, a third secondary winding and a fourth secondary winding; the second end of the first primary winding is electrically connected to the first end of the second primary winding, and the second end of the third primary winding is electrically connected to the first end of the fourth primary winding; the second end of the first secondary winding is electrically connected to the first end of the second secondary winding, and the second end of the third secondary winding is electrically connected to the first end of the fourth secondary winding.

11. The power conversion device according to claim 10, characterized in that: There is a first channel between the first winding post and the third winding post, a second channel between the first winding post and the second winding post, a third channel between the second winding post and the fourth winding post, and a fourth channel between the fourth winding post and the third winding post; the first primary winding is electrically connected in series with the second primary winding, and is wound on the first winding post and the second winding post in an 8-shape; the third primary winding is electrically connected in series with the fourth primary winding, and is wound on the third winding post and the fourth winding post in an 8-shape; the first secondary winding is electrically connected to the second secondary winding, and is wound on the first winding post and the second winding post in an 8-shape; the third secondary winding is electrically connected to the fourth secondary winding, and is wound on the third winding post and the fourth winding post in an 8-shape.

12. The power conversion device according to claim 11, characterized in that: The power conversion device also includes an output positive terminal pin; the first end of the first primary winding and the second end of the second primary winding are arranged adjacent to the third side, the first end of the first primary winding is electrically connected to the half-bridge switch in the same half-bridge unit, and the second end of the second primary winding is electrically connected to the half-bridge capacitor in the same half-bridge unit; the first end of the third primary winding and the second end of the fourth primary winding are arranged adjacent to the first side, the first end of the third primary winding is electrically connected to the half-bridge switch in the same half-bridge unit, and the second end of the fourth primary winding is electrically connected to the half-bridge capacitor in the same half-bridge unit; the first end of the first secondary winding, The second end of the second secondary winding, the second end of the third secondary winding and the first end of the fourth secondary winding are arranged adjacent to the first side, and the second end of the first secondary winding, the first end of the second secondary winding, the first end of the third secondary winding and the second end of the fourth secondary winding are arranged adjacent to the third side; the first end of the first secondary winding, the second end of the second secondary winding, the first end of the third secondary winding and the second end of the fourth secondary winding are respectively electrically connected to a synchronous switch, and the second end of the first secondary winding, the first end of the second secondary winding, the second end of the third secondary winding and the first end of the fourth secondary winding are electrically connected to the output positive pin.

13. A magnetic component, characterized in that: It includes a magnetic core, a primary winding, a first secondary winding and a second secondary winding; the magnetic core includes a first side surface and a third side surface opposite to each other, a second side surface and a fourth side surface opposite to each other, a first winding post, a second winding post and a middle post; the first winding post is arranged adjacent to the first side surface, the second winding post is arranged adjacent to the third side surface, and the middle post is arranged adjacent to the fourth side surface; The first end and the second end of the primary winding are both arranged adjacent to the third side surface, the primary winding is wound around the first winding post and the second winding post from the first end to the second end, and the winding direction of the primary winding on the first winding post from the first end to the second end is opposite to the winding direction on the second winding post; The second end of the first secondary winding and the first end of the second secondary winding are short-circuited, and the short-circuit point is arranged adjacent to the third side surface; the first end of the first secondary winding and the second end of the second secondary winding are both arranged adjacent to the first side surface; the secondary winding is wound around the first winding post and the second winding post in an "8" shape from the first end of the first secondary winding to the second end of the second secondary winding.

14. The magnetic assembly according to claim 13, characterized in that: The first end of the primary winding is arranged between the second winding post and the fourth side surface, and the second end of the primary winding is arranged between the second winding post and the second side surface.

15. The magnetic assembly according to claim 13, characterized in that: The first end of the first secondary winding is arranged between the first winding post and the second side surface, and the second end of the second secondary winding is arranged between the first winding post and the fourth side surface.

16. The magnetic assembly according to claim 14, characterized in that: The first end of the primary winding is electrically connected to two switch elements.

17. The magnetic assembly according to claim 16, characterized in that: The second end of the primary winding is electrically connected to two capacitive elements.

18. The magnetic assembly according to claim 15, characterized in that: The first end of the first secondary winding and the second end of the second secondary winding are both electrically connected to a switch element.

19. The magnetic assembly according to claim 15, characterized in that: The short-circuit point between the first secondary winding and the second secondary winding is electrically connected to a capacitor element.

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