Resonant converter

Abstract

A resonant converter comprises a circuit board, a primary side circuit, a secondary side circuit and a flat plate type transformer, and the flat plate type transformer comprises a through hole, an iron core, a wire and a first filling hole. The primary side circuit and the secondary side circuit are arranged on the circuit board, and the primary side circuit or the secondary side circuit comprises a power element. The power element is embedded into any sub-layer plate, and the flat plate type transformer is electrically connected with the primary side circuit and the secondary side circuit. The through hole penetrates through the circuit board, and the iron core comprises an iron core column penetrating through the through hole. The wiring is formed around the through hole to serve as a winding of the flat plate type transformer. The first filling hole is formed in the circuit board and is used for electrically connecting the power element and the winding which are arranged on the sub-layer board.

Description

Technical Field

[0001] The present invention relates to a resonant converter, and in particular to a resonant converter using a planar transformer. Background Art

[0002] With the rapid development of the information industry, power supplies have played an indispensable role. The input voltage of information and household appliances is divided into AC voltage and DC voltage, and power supplies can generally be divided into two levels. Generally, the front stage is usually an AC / DC converter, a power factor corrector or a DC / DC converter, and the back stage is usually a resonant converter. The resonant converter is a DC-to-DC power converter that can be set to operate in zero voltage switching (Zero Voltage Switching) of the primary side switch and zero current switching (Zero Current Switching) of the secondary side rectifier switch. Therefore, compared with other converters, it has the advantages of high output power and high conversion efficiency. Further, the use of synchronous rectification switches on the secondary side makes it easier to achieve high efficiency and high power density performance.

[0003] Further, as follows Figure 1 This diagram illustrates the internal circuitry of a conventional power supply. The power supply unit (PSU) includes an input circuit CT_I, a power factor corrector (PFC), an auxiliary power circuit AUX, a DC bus capacitor Cap_B, a resonant converter 100, a control circuit MCU, and an output circuit CT_O. The PSU may also optionally include a fan for heat dissipation during operation. The input circuit CT_I receives AC power, performs power factor correction (PFC) on the power factor corrector (PFC), and converts the AC power into DC power, which is then stored in the DC bus capacitor Cap_B. The auxiliary power circuit AUX converts the DC power into auxiliary power to power various components of the PSU that require small amounts of DC power, such as, but not limited to, the controllers, drivers, fans, and LEDs of the converters. The resonant converter 100 converts the DC power into output power and provides this power to a connected load (e.g., a server) via the output circuit CT_O. The control circuit MCU is used to communicate with the load through the output circuit CT_O, and control the power supply PSU based on the communication result.

[0004] In conventional technology, a resonant converter typically includes multiple power components (such as power switches, output capacitors, and drivers), a resonant inductor, and a transformer. These components are typically mounted on a circuit board, and wiring is then routed using routing software to connect these components. Due to the obstruction of these components, wiring must be routed around these components and their solder joints (pads), increasing wiring length and complexity. This results in an inability to reduce the resonant converter's AC impedance and line losses, hindering further efficiency improvements. Summary of the Invention

[0005] Therefore, how to design a resonant converter to solve the problems and technical bottlenecks in the prior art has become an important topic studied by the inventors of this case.

[0006] In order to solve the above problems, the resonant converter disclosed in the present invention includes a circuit board, a primary-side circuit, a secondary-side circuit and a flat-type transformer. The circuit board includes multiple sub-layer boards, and the primary-side circuit and the secondary-side circuit are arranged on the circuit board. The primary-side circuit or the secondary-side circuit includes a power component, and the power component is embedded in any sub-layer board. The flat-type transformer is arranged on the circuit board and electrically connects the primary-side circuit and the secondary-side circuit. A perforation passes through the circuit board, and the iron core includes an iron core column passing through the perforation. The trace is formed around the perforation and serves as the winding of the flat-type transformer. The first injection hole is formed on the circuit board and is used to electrically connect the power component and the winding arranged on the sub-layer board.

[0007] To address the above-mentioned issues, the resonant converter disclosed herein includes a circuit board, a primary-side circuit, a secondary-side circuit, and a flat-plate transformer. The secondary-side circuit includes a first switch, a second switch, and an output capacitor, and the flat-plate transformer includes a through-hole, an iron core, and a secondary-side trace. The circuit board includes multiple sub-layer boards, and the primary-side circuit and the secondary-side circuit are disposed on the circuit board. The first switch, the second switch, and the output capacitor are disposed on the circuit board, and the output capacitor is electrically connected to the first switch and the second switch. The flat-plate transformer is disposed on the circuit board and electrically connected to the first switch, the second switch, and the output capacitor. A through-hole passes through the circuit board, and the iron core includes a first iron core leg passing through the first through-hole. The secondary-side trace is disposed on at least one sub-layer board and formed around the through-hole. One end of the secondary-side trace is electrically connected to the first switch, and the other end of the secondary-side trace is electrically connected to the second switch. The first switch and the second switch are disposed on the same side of the through-hole, and the output capacitor is disposed between the first switch and the second switch.

[0008] One purpose and effect of the present disclosure is that the power components on the power path of the resonant converter of the present disclosure can be embedded in any sub-layer of the circuit board using embedding technology to minimize the AC impedance of the resonant converter and improve the circuit efficiency.

[0009] Another object and effect of the present disclosure is that the component arrangement structure of the secondary side circuit of the resonant converter of the present disclosure can form a ring-shaped current path when the first switch or the second switch is turned on, thereby providing the shortest current path and reducing path loss.

[0010] In order to further understand the techniques, means and effects adopted by the present invention to achieve the intended objectives, please refer to the following detailed description of the present invention and the accompanying drawings. It is believed that the objectives, features and characteristics of the present invention can be further understood in detail. However, the accompanying drawings are provided for reference and illustration only and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic diagram of the internal circuit arrangement of a conventional power supply;

[0012] Figure 2 A schematic diagram of the internal circuit configuration of the power supply of the present disclosure in combination with the integrated power conversion module of the present disclosure;

[0013] Figure 3A is a circuit diagram of a first embodiment of a resonant converter disclosed herein;

[0014] Figure 3B is a circuit diagram of a second embodiment of a resonant converter disclosed herein;

[0015] Figure 3C is a circuit diagram of a third embodiment of a resonant converter disclosed herein;

[0016] Figure 4A A three-dimensional circuit structure diagram of the first embodiment of the resonant converter disclosed herein;

[0017] Figure 4B This is an exploded view of the three-dimensional circuit structure of the first embodiment of the resonant converter disclosed herein;

[0018] Figure 5A A diagram showing the wiring structure of one surface layer of the circuit board of the first embodiment;

[0019] Figure 5B A wiring structure diagram of another surface layer of the circuit board of the first embodiment;

[0020] Figures 6A to 6L Schematic diagrams of the wiring of the windings of the flat-plate transformer of the present disclosure on the circuit board of the first embodiment and on each sub-layer board;

[0021] Figure 7 For this disclosure Figures 6A to 6L The planar transformer is stacked on each sub-layer of the circuit board of the first embodiment, and the magnetomotive force curve when the planar transformer is in operation on the first secondary side;

[0022] Figure 8A A cross-sectional view of a circuit board using embedding technology for the power components of the resonant converter of the present disclosure;

[0023] Figure 8B A top view of a circuit board using embedding technology for the power components of the resonant converter of the present disclosure;

[0024] Figure 8C A circuit diagram showing a configuration in which the power element on the secondary side of the resonant converter disclosed herein is embedded into a surface layer of a circuit board using an embedded technology;

[0025] Figure 8D A circuit configuration diagram showing a power element on the secondary side of the resonant converter disclosed herein being embedded into another surface layer of a circuit board using embedded technology;

[0026] Figure 8E A top view and a cross-sectional view of a circuit board according to a first embodiment of the present disclosure using an embedding technique for routing the planar transformer;

[0027] Figure 8F A top view and a cross-sectional view of a circuit board of a second embodiment of the present disclosure using an embedding technique for routing the planar transformer;

[0028] Figure 8G A side view of a circuit board using embedded technology for routing the power components and planar transformers disclosed herein;

[0029] Figure 9A A diagram showing the arrangement of components of a secondary side circuit of a resonant converter of the present disclosure; and

[0030] Figure 9B FIG2 is a diagram showing component arrangements of the resonant converter according to different secondary-side circuit structures of the present disclosure.

[0031] The reference numerals are as follows:

[0032] PSU: Power Supply Unit

[0033] CT_I: Input circuit

[0034] IN_AC: power input terminal

[0035] EMI: Electromagnetic Interference Filter

[0036] PFC: Power Factor Corrector

[0037] Cap_B: DC bus capacitor

[0038] CM_I: Integrated power conversion module

[0039] MCU: system control circuit

[0040] AUX: Auxiliary power circuit

[0041] CT_O: output circuit

[0042] Fan: fan

[0043] SE: Space

[0044] 100: Resonant Converter

[0045] 100A: Resonant conversion circuit

[0046] CB, CB1, CB2: circuit boards

[0047] Via_A~B、Via_D:filling holes

[0048] LA1~LA12、LA: Sub-layer board

[0049] IN: Input terminal

[0050] OUT: output terminal

[0051] SG:Signal transmission end

[0052] 1A: Primary side circuit

[0053] SP_1: Primary side switch bridge arm

[0054] Q1, Q2: power switches

[0055] Lr: resonant inductor

[0056] CL: Inductor core

[0057] HL: Inductor hole

[0058] Lc: Inductor winding

[0059] Tl: Inductor routing

[0060] Cr: resonant capacitor

[0061] 2A, 2B: Transformer

[0062] PE: Flat type transformer

[0063] H1, H2, H: perforation

[0064] C1, C2: iron core

[0065] C1_1, C1_2, CL_1, CL_2: Cover C1_3, CL_3: Side

[0066] C1_4, CL_4: accommodating groove

[0067] C12: First core column

[0068] C14: Second core column

[0069] GP: Air Gap

[0070] 22: Winding

[0071] T_1(n)~T_3(n), T_1(m)~T_3(m), Tc: routing DW_1, DW_2: extension direction

[0072] AR: Area

[0073] 22A: Primary side winding

[0074] Tp: Primary side wiring

[0075] 22B: Secondary winding

[0076] Ts: Secondary side routing

[0077] 22B-1: First winding

[0078] Ts1: First secondary side routing

[0079] 22B-2: Second winding

[0080] Ts2: Secondary side routing

[0081] MMF: Magnetomotive force

[0082] M0: magnetic flux origin

[0083] M1: first predetermined offset

[0084] Mr: second predetermined offset

[0085] F_D1: first direction flux

[0086] F_D2: Second direction magnetic flux

[0087] CF: Magnetomotive force curve

[0088] 3A: Secondary side circuit

[0089] 32: Rectifier circuit

[0090] SS_1, SS_2: Secondary side switch bridge arms

[0091] SR1, SR2, SR3, SR4: switches

[0092] Co: output capacitance

[0093] 4A, IC_SR: controller

[0094] DC / DC: DC conversion circuit

[0095] 300: Load

[0096] 400: Power components

[0097] AR_H: Hollow area

[0098] Pad, Pad_1, Pad_2: contacts

[0099] Ce:Electronic components

[0100] WM: Modular Winding

[0101] MC: Conductive material

[0102] Pac: AC power supply

[0103] Pdc: DC power supply

[0104] Po: output power

[0105] Paux: Auxiliary power

[0106] I1, I2: current

[0107] Li, Li_1, Li_2: current path DETAILED DESCRIPTION

[0108] The technical content and detailed description of the present invention are now described as follows with reference to the accompanying drawings:

[0109] See also Figure 2The power supply PSU is a schematic diagram of the internal circuit configuration of the disclosed power supply in conjunction with the disclosed integrated power conversion module. The power supply PSU includes an input circuit CT_I, a power factor corrector PFC, a DC bus capacitor Cap_B, an integrated power conversion module CM_I, and an output circuit CT_O. The power supply PSU may also optionally include a fan Fan for heat dissipation during operation. The input circuit CT_I includes a power input terminal IN_AC and an electromagnetic interference filter EMI. The integrated power conversion module CM_I includes a resonant converter 100, a system control circuit MCU, and an auxiliary power circuit AUX. The power supply PSU receives AC power Pac from the power input terminal IN_AC of the input circuit CT_I. After filtering by the electromagnetic interference filter EMI and power factor correction by the power factor corrector PFC, the converted DC power Pdc is converted to DC power Pdc. The converted DC power Pdc is then stored in the DC bus capacitor Cap_B. The DC power Pdc is converted to output power Po by the resonant converter 100 and provided to critical loads (not shown) in the back-end system via the output circuit CT_O. The DC power supply Pdc can also be converted into auxiliary power supply Paux via the auxiliary power circuit AUX. In addition to being provided to non-critical loads (not shown) of the backend system via the output circuit CT_O, it can also be provided internally to peripheral devices such as fans.

[0110] In one embodiment, the system control circuit MCU includes multiple controllers (not shown), each of which can control internal circuits of the power supply (PSU), such as the power factor corrector (PFC), the resonant converter 100, and the auxiliary power circuit AUX. It can also control communication between the power supply (PSU) and external devices (e.g., back-end systems). In another embodiment, the present disclosure integrates the auxiliary power circuit AUX, the resonant converter 100, and the system control circuit MCU into an integrated power conversion module CM_I. This eliminates significant wiring space, at least eliminating space SE (indicated by dashed lines) for the power supply (PSU).

[0111] See also Figures 3A to 3C The circuit diagrams of the first to third embodiments of the resonant converter disclosed in the present invention are shown in FIG. Figures 1 and 2. The resonant converter 100 receives a DC power source Pdc and is electrically connected to a load 300 (i.e., a critical load). The resonant converter 100 is, for example, an LLC converter, and the resonant converter 100 includes a primary-side circuit 1A, a transformer 2A, a secondary-side circuit 3A, and a controller 4A in a system control circuit MCU for controlling the resonant converter 100. One end of the primary-side circuit 1A receives the DC power source Pdc, and the other end is electrically connected to the primary-side winding 22A of the transformer 2A. The secondary-side winding 22B of the transformer 2A is electrically connected to one end of the secondary-side circuit 3A, and the other end of the secondary-side circuit 3A is electrically connected to the load 300. The controller 4A is electrically connected to the primary-side circuit 1A and the secondary-side circuit 3A, and controls the resonant converter 100 to convert the DC power source Pdc into the output power source Po by controlling the connection between the primary-side circuit 1A and the secondary-side circuit 3A.

[0112] The resonant converter 100 includes various implementation structures. For example, the primary side circuit 1A may be a half-bridge type (see Figures 3A to 3C ), full-bridge type, etc. The secondary side circuit 3A can be a half-bridge type, a center tap type (see Figure 3A-3B ), full bridge (see Figure 3C ) and other structures, and the secondary side circuit 3A can be a single group or multiple groups connected in parallel. The number of secondary side windings 22B depends on the number of secondary side circuits 3A, for example Figure 3A 、 3C The number of primary windings 22A is an integer multiple of the number of secondary windings 22B. Figure 3A It's two to two. Figure 3C The resonant converter 100 can also be composed of multiple groups of resonant conversion circuits 100A, for example Figure 3B The architecture consists of two groups Figure 3A The primary side circuit 1A is connected in series through the primary side winding 22A, and the output ends of the secondary side circuit 3A are connected in parallel.

[0113] For reference Figure 3A-3BThe primary-side circuit 1A includes a primary-side switching arm SP_1 and a resonant tank (e.g., a series-connected resonant inductor Lr and resonant capacitor Cr). The primary-side switching arm SP_1 includes two series-connected power switches Q1 and Q2, forming a primary-side topology. The secondary-side circuit 3A includes a rectifier circuit 32 and an output capacitor Co. The rectifier circuit 32 includes a first switch SR1 and a second switch SR2. The secondary-side winding 22B includes a first winding 22B-1 and a second winding 22B-2, each of which is center-tapped. One end of the first winding 22B-1 and the second winding 22B-2 are electrically connected to one end of the first switch SR1 and the second switch SR2, respectively. The other ends of the first winding 22B-1 and the second winding 22B-2 are electrically connected to one end of the output capacitor. The other end of the first switch SR1 and the other end of the second switch SR2 are electrically connected to the other end of the output capacitor, and the output capacitors Co of each set of secondary-side circuits 3A are connected in parallel to form a secondary-side topology.

[0114] The controller 4A controls the primary-side switch bridge arm SP_1 and the first switch SR1 and the second switch SR2 of the rectifier circuit 32 to store / release energy in the resonant tank and the transformer 2A. The DC power Pdc received by the resonant converter 100 is converted into an output power Po through the energy storage / release of the resonant tank and the transformer 2A to supply power to the load 300. Figure 3C and Figure 3A 、 Figure 3B The difference lies in that the rectifier circuit 32 includes secondary-side switching arms SS_1 and SS_2. The secondary-side switching arms SS_1 and SS_2 are connected in parallel and include a first switch SR1 and a third switch SR3 connected in series. The secondary-side switching arm SS_2 includes a fourth switch SR4 and a second switch SR2 connected in series, and the two ends of the secondary-side winding 22B are electrically connected to the series node between the first switch SR1 and the third switch SR3 and the series node between the fourth switch SR4 and the second switch SR2, respectively. In other embodiments, the primary-side circuit 1A, transformer 2A, and secondary-side circuit 3A of the resonant converter 100 may vary based on different design considerations. For example, the primary-side circuit 1A may utilize a full-bridge configuration, the transformer 2A may include only a single primary-side winding 22A and a secondary-side winding 22B, and the secondary-side circuit 3A may utilize a half-bridge configuration, and so on.

[0115] See also Figure 4A This is a three-dimensional circuit structure assembly diagram of the first embodiment of the resonant converter disclosed in the present invention. Figure 4A Mainly, the circuit of the resonant converter 100 (for example: Figures 3A to 3CThe circuit diagram (see Figure 1) is converted into a physical structure in the form of a single circuit board CB, enabling the single circuit board CB to convert DC power Pdc into output power Po. In the physical structure, the resonant converter 100 includes a circuit board CB, a primary-side circuit 1A, a secondary-side circuit 3A, and a planar transformer PE serving as transformer 2A. The circuit board CB comprises multiple sub-layer boards, with an input terminal IN and an output terminal OUT formed at the edge of the circuit board CB. The input terminal IN receives the DC power Pdc, and the output terminal OUT provides the output power Po. The input terminals IN and OUT are formed at the edge of the circuit board CB primarily to allow the circuit board CB to be plugged into any device requiring power conversion, such as a power supply or uninterruptible power supply system. Vertical plugging saves device space.

[0116] The primary-side circuit 1A is disposed on a circuit board CB. The circuit components of the primary-side circuit 1A that are clearly visible on the circuit board CB include the power switches Q1 and Q2 of the primary-side switching leg SP_1 and the inductor core CL that forms the resonant inductor Lr. The secondary-side circuit 3A is disposed on the circuit board CB. The circuit components of the secondary-side circuit 3A that are clearly visible on the circuit board CB include the first switch SR1 and the second switch SR2 of the rectifier circuit 32 and the output capacitor Co. A planar transformer PE electrically connects the primary-side circuit 1A and the secondary-side circuit 3A. The planar transformer PE includes a core C1 that forms the planar transformer PE. The resonant inductor Lr and the planar transformer PE are arranged on the circuit board CB using traces, allowing them to be planarized. This replaces the traditionally bulky wound-type transformer / inductor, thereby reducing the volume occupied by the resonant converter 100. The circuit board CB further includes a system control circuit MCU (including a controller 4A for controlling the resonant converter 100 ), and the system control circuit MCU can communicate with external devices via a signal transmission terminal SG.

[0117] See also Figure 4B This is a three-dimensional circuit structure exploded diagram of the first embodiment of the resonant converter disclosed in the present invention, and is also referred to in conjunction with Figure 4A . Figure 4B The primary components of the planar transformer PE are the inductor core CL of the resonant inductor Lr and the core C1 of the transformer 2A. The planar transformer PE also includes a first through-hole H1, a second through-hole H2, a primary winding 22A, and a secondary winding 22B. The first through-hole H1 and the second through-hole H2 extend through the circuit board CB, respectively, with the primary winding 22A and the secondary winding 22B surrounding the first through-hole H1 and the second through-hole H2. This means that the primary winding 22A and the secondary winding 22B are formed on the sub-layer of the circuit board CB in a routing structure, surrounding the first through-hole H1 and the second through-hole H2. The primary winding 22A and the secondary winding 22B are nested around the core C1 to form the planar transformer PE.

[0118] In this embodiment, the core C1 can be an EI, EE, ER or other type of core. The core C1 includes two covers C1_1 and C1_2, and at least one of the two covers C1_1 and C1_2 forms a first core column C12 and a second core column C14. The two covers C1_1 and C1_2 also include a main body and multiple side portions C1_3, respectively, and the side portions C1_3 of the two covers C1_1 and C1_2 correspondingly protrude from the periphery of the main body. A receiving groove C1_4 is formed between the side portions C1_3 of the two covers C1_1 and C1_2 and the first core column C12 and the second core column C14, and the receiving groove C1_4 is used to accommodate the winding 22 of the transformer 2A. In this embodiment, the winding 22 can be a primary side winding 22A and a secondary side winding 22B, and in other embodiments, for example: the winding 22 can be Figures 3A to 3C At least one of the primary side winding 22A and the secondary side winding 22B.

[0119] The flat-plate transformer PE is formed by the two covers C1_1 and C1_2, so that the first and second legs C12 and C14 extend through the first and second holes H1 and H2 of the circuit board CB, respectively. Portions of the side portions C1_3 of the covers C1_1 and C1_2 are located outside the circuit board CB. In this embodiment, the side portions C1_3 located outside the circuit board CB form an air gap GP. This air gap GP is formed outside the circuit board CB, making it easy to adjust the size of the air gap GP and thus the magnetic resistance of the flat-plate transformer PE, thereby preventing magnetic saturation during circuit operation. In this embodiment, the core C1 includes two legs C12 and C14 extending through the through holes H1 and H2 of the circuit board CB. In other embodiments, for example, the circuit board CB may include only a single through hole H1, with the winding 22 wrapped around this single through hole H1. The single leg C12 of the core C1 extends through this through hole H1, forming the flat-plate transformer PE.

[0120] For reference Figure 4A-4BThe resonant converter 100 further includes an inductor through-hole HL and an inductor winding Lc, and the inductor through-hole HL passes through the circuit board CB. The inductor winding Lc is electrically connected to the winding 22 and surrounds the inductor through-hole HL. The inductor winding Lc is formed on the sub-layer board of the circuit board CB in a routing structure, so that the inductor winding Lc forms a resonant inductor Lr by being sheathed by the inductor core CL. In this embodiment, the inductor core CL can be a core of type UI, UU, etc. The inductor core CL includes two covers CL_1 and CL_2, and the two covers CL_1 and CL_2 each include a main body, and at least one of the two covers CL_1 and CL_2 includes two side portions CL_3. The two side portions CL_3 protrude from the periphery of the main body, and one of the two side portions CL_3 passes through the inductor through-hole HL. A receiving groove CL_4 is formed between the side portions CL_3 of the two covers CL_1 and CL_2. This groove CL_4 accommodates a portion of the inductor winding Lc of the resonant inductor Lr. Portions of the side portions C1_3 of the two covers CL_1 and CL_2 are located outside the circuit board CB. In this embodiment, the side portions C1_3 located outside the circuit board CB form an air gap GP, which functions similarly to the air gap GP of the core C1.

[0121] In one embodiment, Figure 4A 、 Figure 4B The circuit board CB is also provided with an auxiliary power supply circuit AUX, and the auxiliary power supply circuit AUX is electrically connected to the input terminal IN to receive the DC power supply Pdc. The auxiliary power supply circuit AUX can be an isolated conversion circuit (for example: a flyback conversion circuit), and includes a transformer 2B. The transformer 2B is similar to the transformer 2A, and the wiring can be set on the circuit board CB, and the transformer 2B is formed by the iron core C2. The iron core C2 can also correspond to the iron core C1, and form an air gap GP on the side, and its function is also the same as the air gap GP of the iron core C1. In one embodiment, the controller (not shown) of the auxiliary power supply circuit AUX can also be selectively integrated into the system control circuit MCU, which is not limited here. Therefore Figure 4A 、 Figure 4B The single circuit board CB shown can include the auxiliary power circuit AUX, the system control circuit MCU and the resonant converter 100, and saves a lot of wiring space and at least saves Figure 2 Space SE.

[0122] For reference Figure 5A is a wiring structure diagram of one surface layer of the circuit board of the first embodiment, and Figure 5BThis is a wiring diagram of another surface layer of the circuit board of the first embodiment. DC power supply Pdc enters from input terminal IN and passes through the primary-side switch bridge arm SP_1 and resonant inductor Lr to the flat-type transformer PE. DC power supply Pdc is also provided to the auxiliary power circuit AUX, which converts DC power supply Pdc into auxiliary power supply Paux. Through the coupling of primary-side winding 22A and secondary-side winding 22B, the flat-type transformer PE provides energy to the rectifier circuit 32 and output capacitor Co, and finally provides output power Po to the load 300 from the output terminal OUT. According to the above path, the high-current path (referred to as the power path) of the circuit board CB is an n-type path from the input terminal IN to the output terminal OUT, as described above. The system control circuit MCU and its peripheral control and compensation circuits are located in the center of the n-type path, separated from the power path. The signal transmission terminal SG is directly electrically connected to the system control circuit MCU. The system control circuit MCU is short in distance from the power switches Q1, Q2, the first switch SR1, and the second switch SR2, and is less likely to pass through the power path and be separated from the power path. Therefore, noise in the power path is less likely to interfere with signal transmission in the system control circuit MCU, thereby reducing path loss on the transmission path.

[0123] exist Figure 5B In the circuit, the other side opposite the control circuit MCU includes a DC / DC converter circuit, which is primarily composed of several small step-down converters (e.g., Buck). The main reason for configuring several step-down converters is that the auxiliary power Paux converted by the auxiliary power circuit AUX is a single voltage (e.g., but not limited to, 12V). However, certain controllers and drivers on the circuit board CB require different power supplies (e.g., but not limited to, 5V, 3.3V, 1.8V, etc.). Therefore, by using several small step-down converters in the DC / DC converter circuit to convert power, a suitable voltage can be converted to supply these components for normal operation. The power switches Q1 and Q2 of the primary-side switching bridge arm SP_1 are, for example, GaN transistors, and are arranged with the shortest path. The secondary-side winding 22B and the first and second switches SR1 and SR2 are also arranged with the shortest path to facilitate the layout of the output terminal OUT. On the other hand, the routing distances of the secondary winding 22B, the first switch SR1, the second switch SR2, and the output capacitor Co are closely related to their AC impedance. Therefore, the closer the first switch SR1, the second switch SR2, and the output capacitor Co are to the secondary winding 22B, the smaller the AC impedance and the better the efficiency.

[0124] See also Figures 6A to 6LSchematic diagrams of the wiring of the windings of the flat-plate transformer of the present disclosure on each sub-layer board of the first embodiment. In this embodiment, the circuit board CB is taken as an example with 12 sub-layer boards LA1 to LA12, and the sub-layer boards LA1 to LA12 are sequentially from the top board to the bottom board. In other embodiments, the number of layers of the circuit board CB can be increased or decreased according to actual circuit requirements. Figures 3A to 3C Among the traces on sub-layer boards LA1-LA12, inductor trace Tl serves as the inductor winding Lc of resonant inductor Lr, and primary-side trace Tp serves as primary-side winding 22A of transformer 2A. Secondary-side trace Ts serves as secondary-side winding 22B of transformer 2A, and secondary-side trace Ts includes a first secondary-side trace Ts1 and a second secondary-side trace Ts2. First secondary-side trace Ts1 serves as first winding 22B-1, and second secondary-side trace Ts2 serves as second winding 22B-2.

[0125] In this embodiment, the copper foil of the primary-side trace Tp and the copper foil of the inductor trace Tl are integrally formed to form a common routing structure. The primary-side trace Tp and the secondary-side trace Ts are located on different sub-layers LA1-LA12 to ensure even current distribution when current flows through the sub-layers LA1-LA12. In other embodiments, the inductor trace Tl, the primary-side trace Tp, and the secondary-side trace Ts can be located on the same sub-layers LA1-LA12 depending on actual circuit requirements. The primary-side trace Tp and the secondary-side trace Ts are formed and wrapped around the first through-hole H1 and the second through-hole H2, respectively. When the core C1 is placed around the primary-side trace Tp and the secondary-side trace Ts, a closed magnetic circuit is formed to form the transformer 2A. The inductor trace Tl is formed and wrapped around the inductor through-hole HL. When the inductor core CL is placed around the inductor trace Tl, a closed magnetic circuit is formed to form the resonant inductor Lr.

[0126] exist Figure 6C to Figure 6D 、 Figures 6I to 6J In the transformer 2A, the primary-side trace Tp wraps around the first through-hole H1 and the second through-hole H2 at least once (depending on the turns ratio of the transformer 2A) in different directions, forming a ∞-shaped trace. Multiple vias (Via_A) are formed on one side of each of the first through-hole H1 and the second through-hole H2. The vias (Via_A) are located at the end of the primary-side trace Tp and are filled with a conductive material (such as, but not limited to, solder). This allows the primary-side traces Tp of each sub-layer LA3-LA4 and LA9-LA10 to be electrically connected through the vias (Via_A), forming the primary-side winding 22A.

[0127] exist Figure 6A-6B 、 Figures 6E to 6H 、 Figure 6K to Figure 6LIn the example, the secondary-side trace Ts forms an M-shaped trace with the first through-hole H1 and the second through-hole H2. Due to Ampere's right-hand rule, the direction of current determines the direction of the magnetic field. Therefore, the current in the primary-side trace Tp formed around the first through-hole H1 flows in the same direction as the secondary-side trace Ts (e.g., clockwise). The current in the primary-side trace Tp formed around the second through-hole H2 flows in the opposite direction to that of the first through-hole H1 (e.g., counterclockwise). Multiple vias (Via_B) may be included near the output terminal OUT of the secondary-side trace Ts. The vias (Via_B) are filled with conductive material. This allows the secondary-side traces Ts on the sub-layers LA1-LA2, LA5-LA8, and LA11-LA12 to be electrically connected via the vias (Via_B) to form a secondary-side winding 22B.

[0128] exist Figure 6C 、 Figure 6J In the embodiment, the inductor trace T1 is formed and surrounds the inductor through-hole HL. In this embodiment, the copper foil of the inductor trace T1 and the primary side trace Tp is an integrally formed structure, and a portion of the integrally formed copper foil belongs to the inductor trace T1, and the other portion belongs to the primary side trace Tp. In other embodiments, the inductor trace T1 and the primary side trace Tp can be separated, for example, other circuit elements such as a resonant capacitor Cr can be included between the two. In this embodiment, the inductor trace T1, the primary side trace Tp and the secondary side trace Ts are not limited to being arranged in accordance with Figures 6A to 6L The first and second sub-layer boards described later are not the stacking order, but only represent a sub-layer board LA1 and another sub-layer board LA12 in the circuit board CB.

[0129] For reference Figure 7 For this disclosure Figures 6A to 6L FIG1 is a magnetomotive force curve diagram of the planar transformer when operating on the first secondary side of the circuit board, and the wiring stacking structure of the planar transformer on each sub-layer board of the circuit board of the first embodiment. Figure 7 From top to bottom on the left: Figures 6A to 6L The routing stacking structure diagram, and Figure 7 The right side corresponds to Figure 7The magnetomotive force curve CF formed by the stacked structure of the left-side traces. In this embodiment, one cube represents the traces formed by the sub-layer plates LA1-LA12 with the through-holes H1 and H2 as the center (for example, the first secondary-side trace Ts1 and the second secondary-side trace Ts2), and two cubes represent the traces formed by the sub-layer plates LA1-LA12 with the through-holes H1 and H2 as the center (for example, the primary-side trace Tp). The interval between each trace can be regarded as the thickness between each sub-layer plate LA1-LA12. The horizontal axis of the magnetomotive force curve is the magnetomotive force (MMF), and the vertical axis is the position. The origin of the vertical axis is the magnetic flux origin M0, and the left and right sides of the magnetic flux origin M0 respectively include the first predetermined offset M1 and the second predetermined offset Mr.

[0130] In this embodiment, the first predetermined offset M1 and the second predetermined offset Mr are ideal predetermined offsets obtained by calculating the parameters of the transformer 2A. While the actual offsets during actual operation of the transformer 2A may not be completely identical to the first predetermined offset M1 and the second predetermined offset Mr, they may still be within the error range of the first predetermined offset M1 and the second predetermined offset Mr. The primary-side trace Tp is configured such that when the primary-side circuit 1A operates, the primary-side trace Tp generates a first-directional magnetic flux F_D1. The first secondary-side trace Ts1 is configured such that when the first switch SR1 of the secondary-side circuit 3A operates, the first secondary-side trace Ts1 generates a second-directional magnetic flux F_D2 opposite to the first-directional magnetic flux F_D1.

[0131] When the primary-side trace Tp generates a first-direction magnetic flux F_D1, causing a magnetic flux offset, the second-direction magnetic flux F_D2 generated by the first secondary-side trace Ts1 offsets the magnetomotive force MMF in the opposite direction to maintain the first-direction magnetic flux F_D1 and the second-direction magnetic flux F_D2 within a specific range Rm formed by the magnetic flux origin M0 and the first predetermined offset M1 and the second predetermined offset Mr, so that the magnetomotive force curve CF of the flat-plate transformer 2A is maintained within the specific range Rm, thereby maintaining the magnetomotive force MMF in balance.

[0132] Because only the first switch SR1 or the second switch SR2 operates in the same half-cycle in the center-tapped configuration of first winding 22B-1, when first switch SR1 is conductive and second switch SR2 is not conductive, no current path is formed between second winding 22B-2 and rectifier switch SR2. Consequently, the magnetomotive force MMF of second-secondary trace Ts2 does not shift toward the first predetermined offset M1 or the second predetermined offset Mr. Based on the above logic, the magnetomotive force curve when first switch SR1 is not conductive and second switch SR2 is conductive can be inferred, which will not be further described here.

[0133] See also Figure 8AThis is a cross-sectional view of a circuit board using embedded technology for the power components of the resonant converter disclosed herein. In this embodiment, the power path of the resonant converter 100 (see Figure 3A ) on the circuit board CB (e.g., power switches Q1, Q2, first switch SR1, second switch SR2, output capacitor Co (non-electrolytic capacitor), and a driver for driving switches Q1, Q2, SR1, and SR2 into conduction) can be embedded into any of the sub-layers LA1-LA12 (illustrated using sub-layer LA1) within the circuit board CB using embedding technology. The primary purpose and effectiveness of using embedding technology is to minimize the AC impedance AC_R of the resonant converter 100 and thereby improve circuit efficiency. Embedding technology involves hollowing out the resin substrate within the circuit board CB and embedding the power components 400, such as the power switches and driver, within the hollowed-out area AR_H. Then, copper is melted into the pre-set vias Via_D formed on the circuit board CB to form contact pads on the surface, so that the power element 400 can be electrically connected to components such as electronic components Ce (such as capacitors, resistors, etc.), any traces of the winding 22, and electrical traces Tc for electrically connecting to electronic components Ce through the vias Via_D. Figure 8B This is a top view of a circuit board using embedding technology for the power components of the resonant converter disclosed herein. Electronic components Ce (e.g., capacitors, resistors, switches) or electrical traces Tc can be electrically connected to the power component 400 by soldering to contact pads. This technique is used because once the power component 400 is embedded in the hollowed-out area AR_H, the electronic components Ce or electrical traces Tc can be connected to the power component 400 using the shortest possible distance, thereby minimizing the AC impedance AC_R of this connection path.

[0134] For reference Figure 8C and Figure 8D A circuit diagram showing the application of embedded technology to the power elements on the secondary side of the resonant converter of the present disclosure. Figure 8C and Figure 8D The embodiment mainly involves the power element 400 on the secondary side of the resonant converter 100 (e.g., the first switch SR1, the second switch SR2, the controller IC_SR for controlling the first switch SR1 and the second switch SR2, the output capacitor Co, etc., and the output capacitor Co is electrically connected to the first switch SR1 and the second switch SR2 to form the secondary side circuit 3A) can be applied as follows Figures 8A and 8BThe embedded technology shown is used to embed any sub-layer board of the circuit board CB (for example, embedded in the surface boards LA1 and LA12 of the circuit board CB), and then by melting copper into the pre-set vias Via_D, contact pads are generated on the surface of the sub-layer boards LA1 and LA12. As a result, the circuit board CB has only contact pads at the locations of the multiple power components 400, and the power components 400 (first switch SR1, second switch SR2 and output capacitor Co) can be electrically connected to the secondary winding 22B through the corresponding multiple vias Via_D. In one embodiment, the secondary-side power components 400 are disposed in the through-holes H (see also Figure 4B The through-hole H may be on one side of the first through-hole H1 or the second through-hole H2), and the first switch SR1 and the second switch SR2 are respectively arranged on the two sides of the output capacitor Co, and the sub-layer plates LA1 and LA12 are provided with the first secondary-side trace Ts1, and the sub-layer plates LA2 and LA11 are provided with the second secondary-side trace Ts2.

[0135] Since multiple power components 400 are embedded using technology, they will not be affected by the first secondary-side trace Ts1 or other electronic components Ce and controller IC_SR on the surface of the circuit board CB and be forced to adjust to a connection path that is not the shortest distance. When the current I1 flows through the first switch SR1 and the first secondary-side trace Ts1 to the output capacitor Co, a shorter current path can be formed (the same is true for the current I2, and since the power components 400 are all arranged on the sub-layer boards LA1 and LA12, the second secondary-side trace Ts2 of the sub-layer boards LA2 and LA11 can be electrically connected to the power components 400 through the contact Pad).

[0136] For reference Figure 8C and Figure 8D , the embedded technology can also be applied to the primary side of the resonant converter 100. Figures 3A to 3C The primary side circuit 1A includes a primary side switch bridge arm SP_1, and the primary side switch bridge arm SP_1 includes a first power switch Q1 and a second power switch Q2. The first power switch Q1 and the second power switch Q2 can be similar to Figure 8C and Figure 8D The embedding technology is used to embed the switch in any sub-layer of the circuit board CB, and the first power switch Q1 and the second power switch Q2 are electrically connected to the primary winding 22A through corresponding multiple vias Via_D.

[0137] See also Figure 8EThe top and cross-sectional views of a circuit board illustrate a first embodiment of the present disclosure using embedding technology for the planar transformer wiring. In addition to power component 400, the inductor winding Lc of resonant inductor Lr and winding 22 of planar transformer PE can also be embedded using embedding technology within any of the sub-layers LA1-LA12 (illustrated with sub-layer LA1) within circuit board CB. The embedding technology for resonant inductor Lr and planar transformer PE primarily utilizes a modular winding WM structure for inductor winding Lc and winding 22 (i.e., modular winding WM includes inductor wiring Tl for inductor winding Lc, or modular winding WM includes primary wiring Tp or secondary wiring Ts for winding 22). Similarly, the resin substrate within circuit board CB is hollowed out, and the modular inductor winding Lc and winding 22 (i.e., modular winding WM) are embedded within the hollowed-out area AR_H. Copper is then melted into pre-formed vias (Via_D) on the circuit board CB to create contact pads on the surface. This allows the primary circuit 1A or the secondary circuit 3A to electrically connect to the modular winding WM through the vias (Via_D). In one embodiment, the modular winding WM can be formed using a non-conductive material such as resin to form a single-piece routing layer structure for the inductor winding Lc or winding 22. This routing layer structure can then be embedded into the hollowed-out area AR_H of the circuit board CB using embedding technology.

[0138] For reference Figure 8E , and with Figure 6C 、 Figure 6D For example, the primary side traces Tp are used as traces T_1(n) and T_1(m) to form a modular winding WM, and it is assumed that the traces T_1(n) and T_1(m) are embedded in the first sub-layer board LA1. Figure 8E Panel (a) shows a top view of traces T_1(n) and T_1(m), and panel (b) shows a cross-sectional view of traces T_1(n) and T_1(m). Traces T_1(n)-T_3(n) on the first (upper) layer of modular winding WM are arranged in the same extension direction DW_1 and are electrically connected to traces T_1(n)-T_3(n) on the second (lower) layer via conductive material MC (e.g., copper, aluminum, etc., preferably in a columnar structure). Traces T_1(m)-T_3(m) on the lower layer are also arranged in the same extension direction DW_2, so that traces T_1-T_3 extend across the first and second layers in an alternating manner through conductive material MC. In one embodiment, the traces T_1 to T_3 on different layers form an acute angle with the conductive material as the center, and when the acute angle is between 25 degrees and 30 degrees, the AC impedance of the modular winding WM is lower, which is a preferred embodiment. Figure 8EWhen embedding technology is applied to the inductor winding Lc and winding 22 of the resonant converter 100, modularized inductor winding Lc and winding 22 (i.e., modularized winding WM) can also be formed in vias (Via_D) on the circuit board CB, creating contact pads on the surface. The modularized inductor winding Lc can be electrically connected to the primary circuit 1A via the vias (Via_D), and the modularized winding 22 can be electrically connected to the primary circuit 1A or the secondary circuit 3A via the vias (Via_D).

[0139] The first and second layers are similar to Figure 6C 、 Figure 6D The relationship between the stacking of sub-layer boards LA3 and LA4 (i.e., the first layer and the second layer are stacked together), but the first layer and the second layer do not refer to the first sub-layer board LA1 and the second sub-layer board LA2. For example, the first sub-layer board LA1 may include the first layer and the second layer of the modular winding WM arranged on the first sub-layer board LA1, but it can also be that the first layer of the modular winding WM is arranged on the first sub-layer board LA1, and the second layer is arranged on the second sub-layer board LA2. There is no limitation here. Contacts Pad_1 and Pad_2 are formed at the initial ends of the upper-layer traces T_1(n) to T_3(n) and the terminal ends of the lower-layer traces T_1(m) to T_3(m), and the contacts Pad_1 and Pad_2 can be electrically connected to the electrical traces Tc_1 and Tc_2 on the top and bottom surfaces of the first sub-layer board LA1 (that is, which can be the top surface of the second sub-layer board LA2), respectively, so as to electrically connect the power element 400 through the electrical traces Tc_1 and Tc_2.

[0140] For reference Figure 8F The top view and cross-sectional view of the circuit board of the second embodiment of the present disclosure using the embedded technology for the wiring of the flat-plate transformer, and also taking the wiring T_1(n) and T_1(m) to form the modular winding WM as an example. Figure 8F As shown in the top view (a) and the cross-sectional view (b), contacts Pad_1 and Pad_2 are formed at the initial and final ends of upper-layer traces T_1(n)-T_3(n), respectively. Contacts Pad_1 and Pad_2 can be electrically connected to electrical traces Tc_1 and Tc_2 on the top surface of the first sub-layer LA1, thereby electrically connecting to power device 400 through electrical traces Tc_1 and Tc_2. Therefore, electrical traces Tc_1 and Tc_2 are located on the same surface, and an isolation layer or a hollow region (i.e., region AR) is included between them to prevent short circuits between them.

[0141] See also Figure 8G This is a side view of a circuit board using embedded technology for routing the power components and flat-plate transformers disclosed herein. Figures 8A to 8GUsing this technology, a power component 400 and a modular winding WM (including traces T_1(n) and T_1(m)) are embedded in any of the sub-layers LA1-LA12 (for example, both embedded in the first sub-layer LA1) of the circuit board CB. The power component 400 can be electrically connected to the traces T_1(n), T_1(m), T_2(n), and T_2(m) of the modular winding WM through two vias Via_D by connecting an electrical trace Tc_1 to two contacts Pad_1. Furthermore, the modular winding WM can be electrically connected to the electrical trace Tc_2 on the bottom surface of the first sub-layer LA1 (which can be the top surface of the second sub-layer LA2) through contact Pad_2. Therefore, using the embedding technology can shorten the distance between the power element 400 and the traces T_1(n), T_1(m), T_2(n), and T_2(m), thereby minimizing the AC impedance AC_R and improving circuit efficiency.

[0142] In this embodiment, the power component 400 and the traces T_1(n), T_1(m), T_2(n), and T_2(m) of the modular winding WM are embedded in the same sub-layer LA. This effectively shortens the distance between the power component 400 and the traces T_1(n), T_1(m), T_2(n), and T_2(m). For example, the power component 400 is a first switch SR1 embedded in the same sub-layer as the first secondary-side trace Ts1. The first switch SR1 is electrically connected to the first secondary-side trace Ts1 via the electrical trace Tc_1 and the pad Pad_1, effectively shortening the distance between the two. Similarly, this can be done by analogy. In other embodiments, the power element 400 and the traces T_1(n), T_1(m), T_2(n), and T_2(m) of the modular winding WM may also be embedded in a different sub-layer board LA. Compared to the traditional power element 400 that must be set on the surface of the circuit board CB, the power element 400 of the present disclosure does not need to be set on the surface of the circuit board CB, thereby avoiding other components and traces on the surface of the circuit board CB, thereby simplifying the complexity of the circuit design.

[0143] See also Figure 9A The secondary side circuit 3A is disposed on the circuit board CB and includes a first switch SR1, a second switch SR2 and an output capacitor Co. Figures 3A to 3CThe first switch SR1, the second switch SR2, and the output capacitor Co are disposed on the circuit board CB, and the output capacitor Co is electrically connected to the first switch SR1 and the second switch SR2. The secondary-side trace Ts can be disposed on any one or more sub-layers LA1 to LA12 of the circuit board CB and formed around the through-hole H. One end of the secondary-side trace Ts is electrically connected to the first switch SR1, and the other end of the secondary-side trace Ts is electrically connected to the second switch SR2. For example, when the secondary-side trace Ts is disposed on the surface layer of the circuit board CB (e.g., the first sub-layer LA1), the secondary-side trace Ts can be directly connected to the first switch SR1 and the second switch SR2 by soldering a contact pad. Alternatively, when the secondary-side trace Ts is disposed on the inner layer of the circuit board CB (e.g., the second sub-layer LA2), the secondary-side trace Ts can be electrically connected to the first switch SR1 and the second switch SR2 by vias (not shown).

[0144] exist Figure 9A In FIG. 1 , the first switch SR1 and the second switch SR2 are disposed on the same side of the through hole H, and the output capacitor Co is disposed between the first switch SR1 and the second switch SR2. In one embodiment, when there are multiple output capacitors Co, the output capacitors Co can be configured as follows: Figure 9A As shown, they are arranged in parallel in the same direction, or they can be arranged in parallel in pairs. Due to the specific arrangement of the first switch SR1, the second switch SR2 and the output capacitor Co, when the first switch SR1 and the second switch SR2 are turned on, a ring-shaped current path Li is formed, that is, the current flows from one side of the secondary side trace Ts through the first switch SR1, the output capacitor Co, the second switch SR2 to the other side of the secondary side trace Ts. Since the current path Li is in an arc shape, there are no other branches or irregular paths (for example, compare Figure 8C ), so Figure 9A The component setting method can provide the shortest current path Li and reduce path loss.

[0145] See also Figure 9B This is a diagram showing the arrangement of components of the resonant converter according to different secondary side circuit structures. Figure 9A . Figure 9B The main structure is a side view of the output terminal OUT of the circuit board CB, and the first switch SR1, the second switch SR2 and the output capacitor Co are arranged in a manner similar to the embodiment of FIG. Figures 3A to 3C Different secondary side circuits 3A may have different configurations, but may also be configured as follows: Figure 9A The current path Li. Figure 9BIn the (a) panel, the first switch SR1, the second switch SR2 and the output capacitor Co are arranged on the same surface of the circuit board CB, and the first secondary side trace Ts1 and the second secondary side trace Ts2 are respectively arranged on at least any two layers of the circuit board CB (illustrated by the first sub-layer LA1 and the second sub-layer LA2), and Figure 9B The (a) sub-graph is applicable to Figure 3A 、 3B When the first switch SR1 is turned on, current I1 flows from the first switch SR1 on the first sub-layer plate LA1 around the through-hole H to the output capacitor Co, forming a current path Li_1. When the second switch SR2 is turned on, current I2 flows from the second switch SR2 on the second sub-layer plate LA2 around the through-hole H to the output capacitor Co, forming a current path Li_2. Because current paths Li_1 and Li_2 run in opposite directions, they cancel out magnetic flux, improving overall circuit efficiency.

[0146] exist Figure 9B In the sub-diagram (b), the resonant converter 100 includes two sets of secondary-side circuits 3A and two sets of secondary-side traces Ts, and the two sets of secondary-side traces Ts include a first secondary-side trace Ts1 and a second secondary-side trace Ts2. The first switch SR1, the second switch SR2 and the output capacitor Co of the two sets of secondary-side circuits 3A are respectively arranged on two surfaces of the circuit board CB, and the first secondary-side trace Ts1 and the second secondary-side trace Ts2 are respectively arranged on at least any four layers of the circuit board CB (illustrated by sub-layers LA1 and LA2 being provided with the first secondary-side trace Ts1, and sub-layers LA11 and LA12 being provided with the second secondary-side trace Ts2), and Figure 9B The (b) panel is applicable to Figure 3A 、 Figure 3B When the first switch SR1 is turned on, current I1 flows through the sub-layer plates LA1 and LA12 from the first switch SR1 around the through-hole H to the output capacitor Co, forming a current path Li_1. When the second switch SR2 is turned on, current I2 flows through the sub-layer plates LA2 and LA11 from the second switch SR2 around the through-hole H to the output capacitor Co, forming a current path Li_2. This also achieves magnetic flux cancellation and improves the overall circuit efficiency.

[0147] exist Figure 9B In the (c) panel, the first switch SR1, the second switch SR2, and the output capacitor Co are arranged on one surface of the circuit board CB, and the third switch SR3, the fourth switch SR4, and the output capacitor Co are arranged on the other surface of the circuit board CB. The secondary side trace Ts is arranged on at least any two layers of the circuit board CB (illustrated by sub-layers LA1 and LA12), and Figure 9B The (c) sub-image is applicable to Figure 3CWhen the first switch SR1 and the second switch SR2 are turned on, the current I1 flows from the first switch SR1 and the second switch SR2 around the through-hole H in the sub-layer plate LA1 to the output capacitor Co, forming a current path Li_1. When the third switch SR3 and the fourth switch SR4 are turned on, the current I2 in the same routing (i.e., the secondary-side routing Ts) but in the opposite direction flows from the third switch SR3 and the fourth switch SR4 around the through-hole H in the second sub-layer plate LA2 to the output capacitor Co, forming a current path Li_2, and can also achieve the effect of magnetic flux cancellation to improve the overall efficiency of the circuit. In one embodiment, in conjunction with reference to Figure 9A The preferred embodiment is to position the first switch SR1 and the second switch SR2 in a mirror-image arrangement with the output capacitor Co as the center. This arrangement can form substantially identical current paths Li_11 and Li_2, thereby achieving optimal magnetic flux cancellation. Furthermore, the mirror-image arrangement of the first switch SR1 and the second switch SR2 with the output capacitor Co as the center can achieve optimal magnetic flux cancellation. The same applies to the third switch SR3 and the fourth switch SR4.

[0148] For reference Figures 3A to 9B The resonant converter 100 disclosed herein uses a monolithic circuit board CB, which can be selectively combined with embedded technology, component configuration and other technologies according to actual needs to improve the overall efficiency of the resonant converter 100. In one embodiment, Figures 3A to 9B If the winding 22 described in the embodiment is not specifically named, it can be a general term for the primary winding 22A and the secondary winding 22B, refer to the primary winding 22A alone or the secondary winding 22B alone, or even refer to the first winding 22B-1 or the second winding 22B-2 alone, without limitation. In another embodiment, Figures 3A to 9B If the routing described in the embodiments is not specifically named, it may be a general term for the primary side routing Tp and the secondary side routing Ts, refer only to the primary side routing Tp or only to the secondary side routing Ts, or even refer only to the first secondary side routing Ts1 or the second secondary side routing Ts2, and there is no limitation here.

[0149] However, the above description is only a detailed description and drawings of preferred specific embodiments of the present invention. However, the features of the present invention are not limited thereto and are not intended to limit the present invention. The full scope of the present invention shall be based on the following claims. All embodiments that conform to the spirit of the claims of the present invention and similar variations thereof shall be included in the scope of the present invention. Changes or modifications that can be easily conceived by those skilled in the art within the scope of the present invention shall be covered by the following patent scope of the present invention.

Claims

1. A resonant converter, comprising: A circuit board comprising a plurality of sub-layer boards; a primary side circuit, disposed on the circuit board; a secondary side circuit, provided on the circuit board, wherein the primary side circuit or the secondary side circuit comprises a power element, wherein the power element is embedded in any one of the plurality of sub-layer boards; A flat-plate transformer is disposed on the circuit board and electrically connects the primary-side circuit and the secondary-side circuit, and the flat-plate transformer includes: a through hole penetrating the circuit board; an iron core, comprising an iron core leg extending through the through hole; and a trace formed around the through hole and serving as a winding of the flat-plate transformer; and A first via is formed on the circuit board and is used to electrically connect the power element and the winding disposed on the sub-layer board.

2. The resonant converter as claimed in claim 1 , wherein the power element is a plurality of elements and comprises: a first switch, disposed on the circuit board; a second switch disposed on the circuit board; and an output capacitor disposed on the circuit board and electrically connected to the first switch and the second switch to form the secondary side circuit, wherein the first switch, the second switch and the output capacitor are respectively embedded in any sub-layer board of the plurality of sub-layer boards; The trace is a secondary-side trace and serves as a secondary-side winding electrically connected to the secondary-side circuit, and the first switch, the second switch, and the output capacitor are electrically connected to the secondary-side winding through corresponding first vias.

3. The resonant converter as claimed in claim 1 , wherein the power element is a plurality of power elements and comprises: a first power switch, disposed on the circuit board; and a second power switch disposed on the circuit board, wherein the first power switch and the second power switch form a primary-side switch bridge arm of the primary-side circuit, and the first power switch and the second power switch are respectively embedded in any sub-layer board of the plurality of sub-layer boards; The trace is a primary-side trace and serves as a primary-side winding electrically connected to the primary-side circuit, and the first power switch and the second power switch are electrically connected to the primary-side winding through corresponding first vias.

4. The resonant converter of claim 1 , further comprising: a second filling hole formed in the circuit board; The winding is a modular winding embedded in any sub-layer board of the plurality of sub-layer boards, and the modular winding is electrically connected to the primary side circuit or the secondary side circuit through the second via.

5. The resonant converter of claim 4 , wherein the modular winding comprises: A plurality of conductive materials are respectively formed between a first layer and a second layer of the modular winding, and the wiring extends through the plurality of conductive materials in an interlaced manner between the first layer and the second layer. 6 . The resonant converter as claimed in claim 5 , wherein the trace is disposed in a first extending direction on the first layer, and the trace is disposed in a second extending direction on the second layer. 7 . The resonant converter as claimed in claim 6 , wherein the traces on different layers form an acute angle with the conductive material as the center, and the acute angle is between 25 degrees and 35 degrees.

8. The resonant converter of claim 4 , further comprising: An electrical trace is used to electrically connect the first filling hole and the second filling hole, so that the power element is electrically connected to the modular winding through the electrical trace.

9. The resonant converter of claim 1 , wherein the primary-side circuit comprises: A modular winding embedded in any sub-layer of the circuit board, wherein the modular winding includes an inductor trace for forming an inductor winding; A third via is formed on the circuit board and is used to electrically connect the modular winding to the primary side circuit.

10. A resonant converter comprising: A circuit board comprising a plurality of sub-layer boards; a primary side circuit, disposed on the circuit board; A secondary side circuit is provided on the circuit board and includes: a first switch, disposed on the circuit board; a second switch disposed on the circuit board; and an output capacitor disposed on the circuit board and electrically connected to the first switch and the second switch; A flat-plate transformer is disposed on the circuit board and electrically connected to the first switch, the second switch, and the output capacitor, and the flat-plate transformer includes: a through hole penetrating the circuit board; An iron core, comprising a first iron core leg extending through the first through-hole; and a secondary-side trace disposed on at least one of the plurality of sub-layers and formed around the through-hole, wherein one end of the secondary-side trace is electrically connected to the first switch, and the other end of the secondary-side trace is electrically connected to the second switch; The first switch and the second switch are disposed on the same side of the through hole, and the output capacitor is configured between the first switch and the second switch. 11 . The resonant converter as claimed in claim 10 , wherein the first switch and the second switch are positioned in a substantially mirror-image arrangement with the output capacitor as the center.

12. The resonant converter of claim 10 , wherein the secondary-side trace comprises: a first secondary-side trace electrically connected to the first switch; and a second secondary-side trace electrically connecting the second switch and the first secondary-side trace; The first switch, the second switch and the output capacitor are arranged on the same surface of a circuit board, and the first secondary-side trace and the second secondary-side trace are respectively arranged on at least any two layers of the circuit board.

13. The resonant converter according to claim 10 , wherein the resonant converter comprises two sets of secondary-side circuits and two sets of secondary-side traces, and the two sets of secondary-side traces respectively comprise: a first secondary-side trace electrically connected to the first switches of the two sets of secondary-side circuits; and a second secondary-side trace electrically connected to the first secondary-side trace and electrically connected to the second switches of the two sets of secondary-side circuits; Among them, the first switch, the second switch and the output capacitor of the two groups of secondary side circuits are respectively arranged on the two surfaces of the circuit board, and the first secondary side traces and the second secondary side traces of the two groups of secondary side traces are respectively arranged on at least any four layers of the circuit board.

14. The resonant converter as claimed in claim 10, wherein the output capacitor is multiple, and the secondary-side circuit further comprises: a third switch, disposed on the circuit board; and a fourth switch, disposed on the circuit board; The first switch, the second switch, and one of the plurality of output capacitors are arranged on one surface of the circuit board, and the third switch, the fourth switch, and another of the plurality of output capacitors are arranged on another surface of the circuit board, and the secondary side trace is arranged on at least any two layers of the circuit board.

15. The resonant converter of claim 10 , wherein when the first switch is turned on, a first current flows from the first switch around the through-hole to the output capacitor to form a first current path, and when the second switch is turned on, a second current flows from the second switch around the through-hole to the output capacitor to form a second current path, wherein the first current path and the second current path have opposite directions.

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