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 first through hole, an iron core, a plurality of filling holes and a plurality of wires. The primary side circuit, the secondary side circuit and the flat plate type transformer are arranged on the circuit board, and the flat plate type transformer is electrically connected with the primary side circuit and the secondary side circuit. The first through hole penetrates through the circuit board, and the iron core comprises a first iron core column penetrating through the first through hole. The filling hole is used for electrically connecting the first sub-layer board and the second sub-layer board of the circuit board, and the wire is formed around the first through hole to serve as a winding of the flat plate type transformer. The wires extend to the first sub-layer board and the second sub-layer board in a staggered mode through the pouring holes, and the wires on the same layer are arranged in parallel.

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, resonant converters typically include inductive components such as resonant inductors and transformers. These components typically consist of windings, a bobbin, and an iron core. Since the windings must be formed by winding copper wire dozens of times around the bobbin, and then wrapped around the iron core to form a closed magnetic circuit, the resonant inductor and transformer often suffer from the fatal drawback of being bulky, making it difficult to effectively reduce the size of the resonant converter. This results in a bulky power supply with poor power density.

[0005] Because transformer windings are typically made of a single-core wire wound in the same direction, resonant converters used for high-frequency switching have a large AC impedance, resulting in low efficiency. Furthermore, the same winding direction can lead to superposition of magnetic flux, which can easily cause transformer saturation and short circuit during operation. Summary of the Invention

[0006] 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.

[0007] 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, and the flat-type transformer includes a first through-hole, an iron core, a plurality of injection holes and a plurality of traces. The circuit board includes a plurality of sub-layer boards, and the primary-side circuit and the secondary-side circuit are arranged on the circuit board. The flat-type transformer is arranged on the circuit board and electrically connects the primary-side circuit and the secondary-side circuit. The first through-hole passes through the circuit board, and the iron core includes a first iron core column passing through the first through-hole. The injection hole is used to electrically connect the first sub-layer board and the second sub-layer board of the circuit board, and the traces are formed around the first through-hole to serve as the winding of the flat-type transformer. The traces extend alternately to the first sub-layer board and the second sub-layer board through the injection holes, and the traces on the same layer are arranged in parallel.

[0008] To address the other objective described above, the resonant converter disclosed herein includes a circuit board, a primary-side circuit, a secondary-side circuit, and a planar transformer. The secondary-side circuit includes a first switch, a second switch, and an output capacitor, and the planar transformer includes a first through-hole, an iron core, a first via, a second via, a third via, a fourth via, a first secondary-side trace, and a second 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 one end of the output capacitor is electrically connected to one end of the first switch and one end of the second switch. The planar transformer is disposed on the circuit board and electrically connected to the first switch, the second switch, and the other end of the output capacitor. A first through-hole extends through the circuit board, and the iron core includes a first iron core leg extending through the first through-hole. A first via and a second via are formed on a first side and a second side of the first through-hole, respectively, to electrically connect the first and second sub-layer boards of the circuit board. The first switch, the second switch, and the output capacitor are disposed on the second side, and a third via and a fourth via are formed on the first side and the second side, respectively, for electrically connecting the first sub-layer board and the second sub-layer board. A first secondary-side trace is electrically connected to the first switch, and a second secondary-side trace is electrically connected to the second switch and the first secondary-side trace. The first secondary-side trace extends from the first sub-layer board in a first direction surrounding the first through-hole to the first via, extends through the first via to the second sub-layer board, and continues in the first direction to the second side to electrically connect to the output capacitor through the second via. The second secondary-side trace extends from the first sub-layer board in a second direction surrounding the first through-hole to the third via, extends through the third via to the second sub-layer board, and continues in the second direction to the second side to electrically connect to the output capacitor through the fourth via. The first direction and the second direction are opposite directions along the first through-hole.

[0009] The utility model is that the transformer windings of the present invention are planarized on a circuit board by laying out the wiring, and the staggered arrangement of the wiring produces a magnetic flux cancellation effect, thereby achieving the utility model of reducing the AC impedance of the resonant converter.

[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 2A 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 diagram showing the winding arrangement of the toroidal transformer disclosed herein;

[0023] Figure 8B A perspective view of the wiring layout of the first and second embodiments of the toroidal transformer disclosed herein;

[0024] Figure 8C A comparison diagram of the routing of the present disclosure set at different staggered angles;

[0025] Figure 8D The impedance curve diagram of the present disclosure at different routing angles;

[0026] Figure 9A It is the magnetic flux distribution diagram of the wiring disclosed in the present invention;

[0027] Figure 9BA schematic diagram of magnetic flux cancellation in the first embodiment of the present disclosure with staggered routing;

[0028] Figure 9C A schematic diagram of magnetic flux cancellation in a second embodiment of the present disclosure with staggered routing;

[0029] Figure 10A A perspective view of the wiring disclosed herein formed in a winding area;

[0030] Figure 10B For this disclosure Figure 10A Schematic diagram of magnetic flux cancellation after enlarging areas A4 and A5;

[0031] Figure 10C A comparison diagram of the routing of the present disclosure with different widths in the same winding area;

[0032] Figure 10D The impedance curve diagram of the present disclosure is set at different widths under the same winding area;

[0033] Figure 11A Schematic diagram of the wiring arrangement of the flat-plate transformer disclosed in the present invention;

[0034] Figure 11B A perspective plan view of the wiring structure of the flat-plate transformer disclosed herein;

[0035] Figure 11C A three-dimensional perspective view of the wiring structure of the flat-plate transformer disclosed herein;

[0036] Figure 12A A schematic diagram of a secondary side wiring extension using staggered routing in the first embodiment of the present disclosure;

[0037] Figure 12B A schematic diagram of a secondary side wiring extension using staggered routing in the second embodiment of the present disclosure;

[0038] Figure 13 A diagram showing the configuration of staggered laying for the secondary side wiring disclosed herein;

[0039] Figure 14A A cross-sectional view of a circuit board using embedding technology for the power components of the resonant converter of the present disclosure;

[0040] Figure 14B A top view of a circuit board using embedding technology for the power components of the resonant converter of the present disclosure;

[0041] Figure 14C 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;

[0042] Figure 14DA 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;

[0043] Figure 14E 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;

[0044] Figure 14F 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;

[0045] Figure 14G A side view of a circuit board using embedded technology for routing the power components and planar transformers disclosed herein;

[0046] Figure 15A A diagram showing the arrangement of components of a secondary side circuit of a resonant converter disclosed herein;

[0047] Figure 15B Schematic diagram of component arrangement of the resonant converter according to different secondary-side circuit structures;

[0048] Figure 16A A first perspective view of the three-dimensional circuit structure assembly of the second embodiment of the resonant converter disclosed herein;

[0049] Figure 16B A second perspective view of the three-dimensional circuit structure assembly of the second embodiment of the resonant converter disclosed herein;

[0050] Figure 16C A third perspective view of the three-dimensional circuit structure assembly of the second embodiment of the resonant converter disclosed herein;

[0051] Figure 16D This is an exploded view of the three-dimensional circuit structure of the second embodiment of the resonant converter disclosed herein;

[0052] Figure 17A A wiring structure diagram of one surface layer of the first circuit board of the second embodiment;

[0053] Figure 17B A wiring structure diagram of another surface layer of the first circuit board of the second embodiment;

[0054] Figure 18A A wiring structure diagram of one surface layer of the second circuit board of the second embodiment;

[0055] Figure 18B A wiring structure diagram of another surface layer of the second circuit board of the second embodiment;

[0056] Figures 19A to 19HSchematic diagrams of the wiring of the windings of the flat-plate transformer of the present disclosure on the first circuit board and each sub-layer board of the second embodiment;

[0057] Figures 20A to 20H Schematic diagrams of the wiring of the windings of the flat-plate transformer of the present disclosure on the second circuit board of the second embodiment and on each sub-layer board;

[0058] Figure 21A For this disclosure Figures 19A to 19H The planar transformer of the second embodiment is stacked on each sub-layer of the first circuit board, and the magnetomotive force curve diagram when the first circuit board is in operation on the first secondary side; and

[0059] Figure 21B For this disclosure Figures 20A to 20H FIG1 is a magnetomotive force curve diagram of the planar transformer on the wiring stacking structure of each sub-layer board of the second circuit board of the second embodiment, and the second circuit board when operating on the first secondary side wiring.

[0060] The reference numerals are as follows:

[0061] PSU: Power Supply Unit

[0062] CT_I: Input circuit

[0063] IN_AC: power input terminal

[0064] EMI: Electromagnetic Interference Filter

[0065] PFC: Power Factor Corrector

[0066] Cap_B: DC bus capacitor

[0067] CM_I: Integrated power conversion module

[0068] MCU: system control circuit

[0069] AUX: Auxiliary power circuit

[0070] CT_O: output circuit

[0071] Fan: fan

[0072] SE: Space

[0073] 100: Resonant Converter

[0074] 100A: Resonant conversion circuit

[0075] CB, CB1, CB2: circuit boards

[0076] Via_A~Via_H: filling holes

[0077] LA1~LA12, LA, LA1-1~LA1-8, LA2-1~LA2-8: Sub-layer board IN: input terminal

[0078] OUT: output terminal

[0079] SG:Signal transmission end

[0080] 1A: Primary side circuit

[0081] SP_1: Primary side switch bridge arm

[0082] Q1, Q2: power switches

[0083] Lr: resonant inductor

[0084] CL: Inductor core

[0085] HL, HL1, HL2: Inductor perforation

[0086] Lc: Inductor winding

[0087] Tl, Tl-1, Tl-2: Inductor routing

[0088] Cr: resonant capacitor

[0089] 2A, 2B: Transformer

[0090] PE: Flat type transformer

[0091] CB1_H: First circuit board perforation

[0092] CB2_H: Second circuit board through hole

[0093] H1, H2, H3, H4, H: Perforated

[0094] D1: First direction

[0095] D2: Second direction

[0096] C1, C2: iron core

[0097] C1_1, C1_2, CL_1, CL_2: Cover

[0098] C1_3, CL_3: side

[0099] C1_4, CL_4: accommodating groove

[0100] C12: First core column

[0101] C14: Second core column

[0102] GP: Air Gap

[0103] 22: Winding

[0104] T_1~T_n, T_(n), T_(m), T_1(n)~T_n(n), T_1(m)~T_n(m), Tc, Tc_1, Tc_2: wiring

[0105] DW_1, DW_2: extension direction

[0106] θ: angle

[0107] DC_R: DC resistance

[0108] AC_R: AC impedance

[0109] T_R: total impedance

[0110] RS_1, RS_2: Range

[0111] Fi, Fo: magnetic flux

[0112] Fi_t, Fo_t: total magnetic flux

[0113] A1~A6、AR: Area

[0114] AS_1~AS_3: Winding area

[0115] 22A: Primary side winding

[0116] Tp, Tp-1, Tp-2: primary side wiring

[0117] 22B: Secondary winding

[0118] Ts, Ts-1, Ts-2, Ts_1~Ts_n: secondary side wiring

[0119] 22B-1: First winding

[0120] Ts1, Ts1-1, Ts1-2, Ts1_(n), Ts1_(m): first secondary side routing

[0121] 22B-2: Second winding

[0122] Ts2, Ts2-1, Ts2-2, Ts2_(n), Ts2_(m): Second secondary side wiring SI_1, SI_2: Insulation section

[0123] PC_1, PC_2: conductive columns

[0124] PC: Pillar

[0125] MMF: Magnetomotive force

[0126] M0: magnetic flux origin

[0127] M1: first predetermined offset

[0128] Mr: second predetermined offset

[0129] F_D1: first direction flux

[0130] F_D2: Second direction magnetic flux

[0131] CF, CF1, CF2: magnetomotive force curves

[0132] 3A: Secondary side circuit

[0133] 32: Rectifier circuit

[0134] SS_1, SS_2: Secondary side switch bridge arms

[0135] SR1, SR2, SR3, SR4: switches

[0136] Co: output capacitance

[0137] 4A, IC_SR: controller

[0138] DC / DC: DC conversion circuit

[0139] 300: Load

[0140] 400: Power components

[0141] AR_H: Hollow area

[0142] Pad, Pad_1, Pad_2: contacts

[0143] Ce:Electronic components

[0144] WM: Modular Winding

[0145] MC: Conductive material

[0146] Pac: AC power supply

[0147] Pdc: DC power supply

[0148] Po: output power

[0149] Paux: Auxiliary power

[0150] I1, I2: current

[0151] Li, Li_1, Li_2: current path DETAILED DESCRIPTION

[0152] The technical content and detailed description of the present invention are now described as follows with reference to the accompanying drawings:

[0153] 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.

[0154] 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).

[0155] 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.

[0156] The resonant converter 100 includes various implementation structures. For example, the primary side circuit 1A may be a half-bridge type (see Figure 3A to Figure 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 、 Figure 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.

[0157] 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.

[0158] 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.

[0159] 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: Figure 3A to Figure 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.

[0160] 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.

[0161] 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.

[0162] 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 Figure 3A to Figure 3C At least one of the primary side winding 22A and the secondary side winding 22B.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] 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.

[0167] 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.

[0168] 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. Figure 3A to Figure 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.

[0169] 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.

[0170] 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.

[0171] exist Figures 6A and 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.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] 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.

[0176] 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.

[0177] See also Figure 8AThis is a diagram showing the winding arrangement of the toroidal transformer disclosed herein. Figure 8A In the (a) diagram, the winding 22 of the transformer 2A is arranged in a ring-shaped space and is copper-plated in a whole piece. Its structure is similar to Figures 6A to 6L The primary side traces Tp and secondary side traces Ts of each sub-layer board LA1 to LA12 are laid with an integrally formed copper foil in the direction of the trace extension. In one embodiment, unless otherwise specified, the winding 22 can be the primary side winding 22A and / or the secondary side winding 22B. Since the copper foil is extended in an integral manner, the winding 22 in the (a) panel has a lower DC impedance. Figure 8A In panel (b), the windings 22 of each sub-layer board LA1-LA12 (e.g., primary winding 22A or secondary winding 22B) form a structure with multiple parallel, oriented wiring. The wiring between each layer (e.g., primary wiring Tp or secondary wiring Ts) is arranged in a staggered, overlapping pattern. This structure of multiple parallel, oriented wiring is similar to litz wire (commonly known as stranded wire), primarily using multiple insulated conductors wound around each other. The characteristic of the wiring structure in panel (b) of 8A is that it effectively reduces AC impedance. This is particularly true when the resonant converter 100 is used in high-frequency switching applications, where it can significantly reduce AC impedance.

[0178] See also Figure 8B Schematic diagram of the wiring layout of the first and second embodiments of the toroidal transformer of the present disclosure. Figure 8B The diagram shows two sub-layer boards LA1 and LA2, with multiple vias (Via_C) located around the periphery of the winding area where the winding 22 is located. The vias (Via_C) are used to electrically connect the first sub-layer board LA1 and the second sub-layer board LA2, and traces T_1 to T_3 are formed around the through-hole H. Trace T_1 is used as an example, and (n) and (m) represent sub-layer boards LA1 and LA2 on different layers, respectively. Trace T_1(n) of the first sub-layer board LA1 extends from the periphery of the winding area where the winding 22 is located to the vias (Via_C) located around the through-hole H, and is electrically connected to the second sub-layer board LA2 via the vias (Via_C). Trace T_1(m) of the second sub-layer board LA2 extends from the vias (Via_C) to the vias (Via_C) located around the periphery of the winding area where the winding 22 is located, and is then electrically connected to the first sub-layer board LA1 via the vias (Via_C). Through vias (Via_C), traces T_1-T_3 can be staggered across the first and second sub-layers LA1 and LA2. Once the entire routing area is fully filled, traces T_1-T_3 on the same layer are arranged parallel to each other. Traces T_1(n)-T_3(n) on the first sub-layer LA1 can overlap traces T_1(m)-T_3(m) on the second sub-layer LA2, forming a staggered arrangement.

[0179] For reference Figure 8C This is a comparison diagram of the wiring of the present invention set at different staggered angles. Figure 8C In the embodiment, multiple traces T_1 to T_n are arranged in an overlapping and staggered manner. Taking trace T_1 as an example, trace T_1(n) of the first sub-layer board LA1 and trace T_1(m) of the second sub-layer board LA2 form an acute angle (angle θ is less than 90 degrees) with the via Via_C as the center, and the angle θ refers to the angle between trace T_1(n) of the first sub-layer board LA1 and trace T_1(m) of the second sub-layer board LA2. Figure 8C In the (a) diagram, the angle θ of the traces T_1(n) and T_1(m) is 45 degrees, and Figure 8C In the (b) panel, the angle θ of the traces T_1(n) and T_1(m) is 30 degrees.

[0180] For reference Figure 8D This is the impedance curve diagram of the present invention at different routing angles. Figure 8C In the (a) panel, when the angle θ of traces T_1(n) and T_1(m) is 45 degrees, the measured DC resistance DC_R is 20m ohms, and the AC resistance AC_R is 5.4m ohms. The total resistance T_R is approximately 23.5m ohms. Figure 8C In panel (b), when the angle θ between traces T_1(n) and T_1(m) is 30 degrees, the measured DC resistance (DC_R) is 14.2mΩ, and the AC resistance (AC_R) is 8.8mΩ, resulting in a total impedance (T_R) of approximately 16.5mΩ. Therefore, when the angle θ between traces T_1(n) and T_1(m) is 30 degrees, the total impedance (T_R) is low. When the angle θ is within the range RS_1 between 25 and 30 degrees, the AC resistance (AC_R) is not excessively high, and the total impedance (T_R) is lower on the curve, representing a preferred embodiment.

[0181] See also Figure 9A This is the magnetic flux distribution diagram of the wiring disclosed in this invention. Figure 9A In the small figure (a), the direction of the arrow indicates the extension direction of the trace T_(n) of the first sub-layer board LA1, and when the current flows in the direction of the arrow, magnetic fluxes Fi and Fo are generated on both sides of the arrow (in this embodiment, i and o represent the directions of entry and exit). Figure 9A In panel (b), the arrows indicate the extension direction of trace T_(m) on the second sub-layer LA2. When current flows in the arrowed direction, magnetic fluxes Fi and Fo are generated on both sides of the arrows. Because the extension directions of panels (a) and (b) intersect, the directions of the magnetic fluxes Fi and Fo are opposite.

[0182] For reference Figure 9BThis is a schematic diagram of flux cancellation in the first embodiment of the present invention with staggered routing. When the first sub-layer board LA1 and the second sub-layer board LA2 are stacked together, the magnetic fluxes Fi and Fo of the two layers overlap, generating total magnetic fluxes Fi_t and Fo_t. The total magnetic fluxes Fi_t and Fo_t in regions A1 and A2 cancel each other out because the magnetic fluxes Fi and Fo in panels (a) and (b) are in opposite directions. This results in smaller total magnetic fluxes Fi_t and Fo_t in regions A1 and A2 (indicated by smaller circles). In the other two regions, the opposite occurs, resulting in larger total magnetic fluxes Fi_t and Fo_t (indicated by larger circles).

[0183] For reference Figure 9C Schematic diagram of magnetic flux cancellation in the second embodiment of the present disclosure with staggered routing. Figure 9C Mainly Figure 9B The structures are arranged side by side, and the traces T_1(n) and T_2(m) are set on different sub-layer boards LA1 and LA2, and the traces T_1(m) and T_2(n) are also set on different sub-layer boards LA1 and LA2. The traces T_1(n) and T_2(m) are arranged side by side with T_1(m) and T_2(n), and are connected to the different sub-layer boards LA1 and LA2 through vias (not shown) to form area A3. Area A3 can be mainly regarded as Figure 9B The total magnetic fluxes Fi_t and Fo_t of the two areas A1 and A2 overlap, and their total magnetic fluxes Fi_t and Fo_t are offset because their directions are positive and negative, making the total magnetic fluxes Fi_t and Fo_t in area A3 smaller, and the total magnetic fluxes Fi_t and Fo_t in the remaining areas larger due to the superposition of magnetic fluxes.

[0184] See also Figure 10A FIG. 4 is a perspective view of the wiring of the present disclosure formed in the wiring area. Figure 10A The second sub-layer board LA1 and LA2 are also used as an example, and a plurality of vias (not shown) electrically connecting the first sub-layer board LA1 and the second sub-layer board LA2 are formed around the winding area AS_1 where the traces T_1 to T_n are set. Figure 10A The principle is similar to Figure 9C , mainly utilizes the staggered routing structure to achieve the effect of magnetic flux cancellation, and expands its application range to the entire winding area AS_1.

[0185] For reference Figure 10B For this disclosure Figure 10A Schematic diagram of magnetic flux cancellation after enlarging areas A4 and A5. Figure 10B The (a) sub-figure mainly shows Figure 10AThe wiring structure of area A4 is shown in Figure 1. The wiring on the first sub-layer board LA1 is sequentially T_1(n) to T_3(n), and the wiring on the second sub-layer board LA2 is sequentially T_4(m) to T_6(m). Figure 9B Therefore, the entire area A4 is like Figure 9B In the areas A1 and A2, there is a magnetic flux cancellation effect. Figure 10B The (b) sub-figure mainly shows Figure 10A The routing structure of area A5 is shown in Figure 1. The routing on the first sub-layer LA1 is sequentially T_7(n) to T_9(n). The routing on the second sub-layer LA2 is sequentially T_8(m) to T_10(m), and routing T_9(m) is an extension of routing T_9(n) through a via, belonging to the same path. Since the surrounding areas of area A5, except for area A6, are similar, Figure 9B Therefore, except for area A6, the rest of area A5 is the same as Figure 9B The areas A1 and A2 also have the effect of magnetic flux cancellation. Figure 10B See also the characteristics of Figure 10A Except for the periphery of the winding area AS_1 which has the same structure as the area A6 and does not have the magnetic flux cancellation effect, the rest of the winding area AS_1 has the magnetic flux cancellation effect, thereby achieving the effect of reducing the core loss and copper wire loss.

[0186] See also Figure 10C This is a comparison diagram of the wiring disclosed in the present invention with different widths set in the same winding area. Figure 10C In the embodiment, the plurality of traces T_1 to T_18 are arranged in a staggered manner in an overlapping manner within the same winding area AS_2. Figure 10C In the (a) panel, the traces T_1 to T_10 are wider and 10 traces T_1 to T_10 are formed in the routing area AS_2. Figure 10C In panel (b), traces T_1-T_18 are narrow, resulting in 18 traces T_1-T_18 within the routing area AS_2. When traces T_1-T_10 are wider, the DC impedance is lower, but the AC impedance is higher. The opposite is true when the traces are narrower. Therefore, adjusting the width of traces T_1-T_18 affects the number of traces T_1-T_8 and can simultaneously adjust both the AC and DC impedances. Another factor affecting AC impedance is the distance between traces T_1-T_18. When the distance between traces T_1-T_18 is closer, the AC impedance is lower, and vice versa. Therefore, within the routing area AS_2, adjusting the distance and width of traces T_1-T_18 can effectively reduce the AC impedance. If the AC impedance allows, the DC impedance can be improved by increasing the width of traces T_1-T_18.

[0187] For reference Figure 10D This is the impedance curve diagram of the present invention under the same winding area with different width settings. Figure 10C The (a) panel includes 10 traces T_1 to T_10 that are wider than those in the (b) panel, and the distance between traces T_1 to T_18 is greater. The measured AC impedance AC_R and DC impedance DC_R are 9.4m ohms and 10m ohms respectively, and the total impedance T_R is approximately 18m ohms. Figure 10C Panel (b) includes 18 narrower traces T_1-T_18 than those in panel (a), and the distance between traces T_1-T_18 is closer. The measured AC impedance AC_R and DC impedance DC_R are 6.8mΩ and 11mΩ, respectively, converting to a total impedance T_R of approximately 16mΩ. Therefore, within the same routing area AS_2, when the number of traces T_1-T_18 falls within the range RS_2 of 16-18, the AC impedance AC_R is not excessively high, and the total impedance T_R is located lower on the curve, indicating a preferred implementation.

[0188] See also Figure 11A This is a schematic diagram of the wiring arrangement of the flat-plate transformer disclosed in the present invention. Figure 11A In the embodiment, the winding 22 of the flat transformer PE is mainly used Figures 8A to 10D The flat-plate transformer PE includes a plurality of vias (Via_C) for electrically connecting the first sub-layer LA1 and the second sub-layer LA2. The vias (Via_C) are formed around the periphery of the winding area AS_3 and the peripheries of the through-holes H1 and H2. The flat-plate transformer PE also includes a plurality of traces (T_1-T_n), which are formed in the winding area AS_3.

[0189] At Figure 11A In the embodiment, the solid arrow represents the extension direction DW_1 of the trace T_1(n) of the first sub-layer board LA1, and the dotted arrow represents the extension direction DW_2 of the trace T_1(m) of the second sub-layer board LA2, and the extension directions DW_1 and DW_2 are continuous from head to tail; in order to concisely and clearly illustrate the arrangement of the winding 22, only a single trace T_1(n) and T_1(m) are shown for illustration. At the head end of the arrow, the trace T_1(n) of the first sub-layer board LA1 extends from the arrow's extension direction DW_1 to the via hole Via_C at the periphery of the winding area AS_3, and extends to the second sub-layer board LA2 through the via hole Via_C, and then extends from the extension direction DW_2 to the via hole Via_C at the periphery of the first through-hole H1, and so on, repeatedly and alternately extending to the first sub-layer board LA1 and the second sub-layer board LA2 until the tail end of the arrow. For reference, Figure 11BThis is a perspective plan view of the wiring structure of the flat-plate transformer disclosed herein. Traces T_2-T_n are arranged parallel to trace T_1 and wind around the entire winding area AS_3, forming a winding 22 comprised of multiple traces T_1-T_n. In one embodiment, since vias Via_C are formed around the perimeter of winding area AS_3 and the perimeters of through-holes H1 and H2, copper casting (castellation) can be used to implement the circuit board CB sidewalls.

[0190] In this embodiment, the angles θ of the traces T_(n) and T_(m) at both ends of the via_C can be combined with the reference Figures 8A to 8D Adjust the width of the traces T_1 to T_n and the distance between the traces T_1 to T_n. Figures 10A to 10D In this embodiment, the sub-layer boards LA1 and LA2 are the layers for setting the secondary side winding 22B, so the traces T_1 to T_n are multiple secondary side traces Ts_1 to Ts_n, which are used to electrically connect the secondary side winding 22B of the secondary side circuit 3A. Figures 6A and 6B 、 Figures 6E to 6H 、 Figure 6K to Figure 6L , Figure 11B The staggered secondary side traces Ts_1 to Ts_n can replace the first secondary side trace Ts1 or the second secondary side trace Ts2, and apply Figures 8A to 10D The angle θ, line width and line spacing are set by the technology, and Figure 6C to Figure 6D 、 Figures 6I to 6J The primary side trace Tp can be applied or not Figures 8A to 10D 、 Figures 11A and 11B The staggered routing setting technology can be set according to the level of AC impedance AC_R and the uniformity of magnetic flux.

[0191] In other embodiments, Figure 6C to Figure 6D 、 Figures 6I to 6J The primary side trace Tp can also be applied Figure 11B The staggered arrangement of the traces T_1 to T_n (not shown) is applied. Figures 8A to 10D The angle θ, line width and line spacing are set by the technology, and Figures 6A and 6B 、 Figures 6E to 6H 、 Figure 6K to Figure 6L The first secondary side trace Ts1 or the second secondary side trace Ts2 can be applied or not. Figures 8A to 10D 、 Figures 11A and 11B The arrangement can be performed by staggered arrangement of the wiring, which can be determined according to the level of the AC impedance AC_R and the uniformity of the magnetic flux. In another embodiment, Figure 6C 、 Figure 6J The inductor trace Tl can also be applied selectively Figure 11B The staggered arrangement of the traces T_1 to T_n (not shown) is applied. Figures 8A to 10D The angle θ, line width and line spacing are set using the technology.

[0192] For reference Figure 11C This is a perspective view of the wiring structure of the flat-plate transformer disclosed herein. The sub-layers LA1 and LA2 of the flat-plate transformer PE, which house the secondary-side traces Ts, also include insulating segments SI_1 and SI_2 extending from through-holes H1 and H2 to the periphery of the winding area AS_3. These insulating segments SI_1 and SI_2 prevent the traces Ts_1-Ts_n from extending in directions DW_1 and DW_2, encircling through-holes H1 and H2, and then electrically connecting to the traces Ts_1-Ts_n at the arrowheads. This could cause a short circuit in the winding 22 when currents I1 and I2 flow through them. The insulating segments SI_1 and SI_2 also include a plurality of vias (Via_C) around their peripheries. These vias allow the traces Ts_1-Ts_n to extend alternately between the first and second sub-layers LA1 and LA2. The size of winding area AS_3 is primarily determined by the slot C1_4 housing winding 22 of transformer 2A. A larger slot C1_4 results in a larger winding area AS_3, and vice versa. Because the side portion C1_3 of core C1, located on the outer side of circuit board CB, forms an air gap GP, at least one side of winding area AS_3 can be aligned with core C1 and formed on the outer side of circuit board CB.

[0193] See also Figure 12A This is a schematic diagram of the secondary side wiring using staggered routing in the first embodiment of the present disclosure. Figure 12A In this embodiment, the first secondary-side trace Ts1_(n) of the first winding 22B-1 extends away from the first switch SR1 to the first secondary-side trace Ts1_(m) on another layer. The same applies to the second secondary-side traces Ts2_(n) and Ts2_(m) of the second winding 22B-2. The difference is that the second secondary-side traces Ts2_(n) and Ts2_(m) are laid in the opposite direction of the first secondary-side traces Ts1_(n) and Ts1_(m), forming an interleaving arrangement. In this embodiment, the planar transformer PE includes a first via Via_E, a second via Via_F, a third via Via_G, and a fourth via Via_H. The first via Via_E and the second via Via_F are respectively formed on a first side and a second side opposite to the first side of the first through-hole H1 , and are used to electrically connect the first sub-layer LA1 and the second sub-layer LA2 of the circuit board CB.

[0194] The third via Via_G and the fourth via Via_H are formed on a first side and a second side opposite the first side of the first through-hole H1, respectively. The third via Via_G and the fourth via Via_H are used to electrically connect the first sub-layer LA1 and the second sub-layer LA2 of the circuit board CB. In this embodiment, the second side is the side closest to the output terminal OUT, and the first side is located on the other side of the first through-hole H1. The first switch SR1, the second switch SR2, and the output capacitor Co are disposed on the second side.

[0195] like Figure 12A As shown in the (a) panel, the first secondary-side trace Ts1_(n) can be located on the first sub-layer LA1 and electrically connected to the first switch SR1. The first secondary-side trace Ts1_(n) extends from the first sub-layer LA1 in a first direction D1 surrounding the first through-hole H1 to the first via Via_E, and then extends to the second sub-layer LA2 through the first via Via_E. Figure 12A As shown in the sub-figure (b), the first secondary-side trace Ts1_(m) extending to the second sub-layer board LA2 continues the first direction D1 and extends to the second side to be electrically connected to the output capacitor Co through the second via Via_F.

[0196] The second secondary-side trace Ts2_(n) can be located on the first sub-layer LA1 and electrically connected to the second switch SR2. The second secondary-side trace Ts2_(n) extends from the first sub-layer LA1 in the second direction D2 surrounding the first through-hole H1 to the third via Via_G, and then extends to the second sub-layer LA2 through the third via Via_G. The second secondary-side trace Ts2_(m) extending to the second sub-layer LA2 continues in the second direction D2 to the second side and electrically connects to the output capacitor Co through the fourth via Via_H. Figure 12A In panels (a) and (b), the first switch SR1 and the second switch SR2 are respectively arranged on opposite sides of the second via Via_F (fourth via Via_H), and the first direction D1 and the second direction D2 are in opposite directions along the first through-hole H1 to form a ring-shaped staggered routing structure.

[0197] See also Figure 12B This is a schematic diagram of the secondary side wiring using staggered routing in the second embodiment of the present disclosure. Figure 12B In the embodiment, the first via Via_E and the second via Via_F are formed on the third side and the fourth side opposite to the third side of the second through hole H2, respectively, and the first via Via_E and the second via Via_F are used to electrically connect the first sub-layer board LA1 and the second sub-layer board LA2 of the circuit board CB. Figure 12AThe first side may be the same side, and the fourth side and the second side may be the same side, the only difference being that the positions of the first through hole H1 and the second through hole H2 are different.

[0198] For reference Figure 12B As shown in panels (a) and (b), the first secondary-side trace Ts1_(n) extends from the first sub-layer LA1 in the second direction D2, surrounding the second through-hole H2, to the first via Via_E, and then extends to the second sub-layer LA2 through the first via Via_E. The first secondary-side trace Ts1_(m) extending to the second sub-layer LA2 continues in the second direction D2 to the fourth side and is electrically connected to the output capacitor Co through the second via Via_F.

[0199] The second secondary-side trace Ts2_(n) extends from the first sub-layer LA1 in the first direction D1, surrounding the second through-hole H2, to the third via Via_G. It then extends to the second sub-layer LA2 through the third via Via_G. The second secondary-side trace Ts2_(m) extending to the second sub-layer LA2 continues in the first direction D1 to the fourth side and is electrically connected to the output capacitor Co through the fourth via Via_H. Figure 12B and Figure 12A Another difference is that the first secondary-side traces Ts1_(n), Ts1_(m) and the second secondary-side traces Ts2_(n), Ts2_(m) are located at opposite positions on the left and right, and extend in opposite directions.

[0200] pass Figure 12A 、 Figure 12B By employing a loop-shaped, staggered routing structure, the current paths of the first secondary-side traces Ts1_(n) and Ts1_(m) and the second secondary-side traces Ts2_(n) and Ts2_(m) can be precisely aligned in opposite directions. Furthermore, the loop-shaped current paths form the shortest current path. This achieves magnetic flux cancellation and reduces the AC impedance AC_R of the secondary-side circuit 3A, thereby improving the efficiency of the resonant converter 100.

[0201] For reference Figure 13 The secondary side wiring of this disclosure uses a staggered layout. Figure 6A-6B 、 Figures 6E to 6H 、 Figure 6K to Figure 6L In the example, since the secondary side trace Ts forms an M-shaped trace with the first through hole H1 and the second through hole H2, the Figure 12A 、 Figure 12B The staggered laying of the wiring extension is integrated together to form Figure 13 As shown in Figure 13(a), when the two sides of the m-shaped trace are the first secondary trace Ts1_(n), Figure 12A 、 Figure 12BThe two sets of second secondary side traces Ts2_(n) in the first direction D1 and the second direction D2 can be sandwiched between the first secondary side traces Ts1_(n). Figure 12A 、 Figure 12B The two sets of second-secondary side traces Ts2_(n) have the same properties, so they can be integrated into an integrated configuration. As shown in the small figure 13(b), when the two sides of the M-shaped trace are the second-secondary side traces Ts2_(n), Figure 12A 、 12B The two sets of first secondary-side traces Ts1_(n) in the first direction D1 and the second direction D2 can be sandwiched between the second secondary-side traces Ts2_(n), and thus can be integrated into an integral configuration.

[0202] In one embodiment, Figures 11A to 11C The staggered arrangement of the traces can be Figures 12A to 13 The structure of staggered routing is applied in combination. The staggered routing structure is applied to at least one of the primary-side routing Tp and the secondary-side routing Ts, so at least two layers of sub-layer boards are required, such as LA1 and LA2. The staggered routing structure is applied to the secondary-side routing Ts, so at least two layers of sub-layer boards are required, such as LA3 and LA4. Therefore, if the two are used in combination, the staggered routing structure and the staggered routing structure require four layers of sub-layer boards LA1, LA2, LA3, and LA4, and an additional layer is added to set the other primary-side routing Tp and the secondary-side routing Ts, but the staggered routing structure and the staggered routing structure are not applied. Sub-layer board, for example, LA5.

[0203] Assuming that the staggered routing structure is applied to the first secondary-side routing Ts1 and the second secondary-side routing Ts2, and that the staggered routing structure is also applied to the first secondary-side routing Ts1 and the second secondary-side routing Ts2: the first secondary-side routing Ts1 can be staggered and extended on the sub-layers LA1 and LA2. When the first secondary-side routing Ts1_(n) extends from the first sub-layer LA1 to the first via Via_E, it extends from the first via Via_E to the third sub-layer LA3 and then extends in a staggered manner along the first direction D1 to the second side. When the first secondary-side routing Ts1_(m) extends from the second sub-layer LA2 to the first via Via_E, it extends from the first via Via_E to the fourth sub-layer LA4 and then extends in a staggered manner along the first direction D1 to the second side.

[0204] When the second secondary-side trace Ts2_(n) extends from the first sub-layer LA1 to the third via Via_G, it extends from the third via Via_G to the third sub-layer LA3 and then extends in a staggered manner along the second direction D2 to the second side. When the second secondary-side trace Ts2_(m) extends from the second sub-layer LA2 to the third via Via_G, it extends from the third via Via_G to the fourth sub-layer LA4 and then extends in a staggered manner along the second direction D2 to the second side.

[0205] See also Figure 14A This 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 T_1(n), T_1(m), T_2(n), T_2(m) of the winding 22, and electrical traces Tc for electrically connecting to the electronic components Ce through the vias Via_D. Figure 14B 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.

[0206] For reference Figure 14C and Figure 14D 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 14C and Figure 14DThe 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 14A and 14B The 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 preset 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 side 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 Figures 11A to 11C 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.

[0207] 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).

[0208] For reference Figure 14C and Figure 14D , the embedded technology can also be applied to the primary side of the resonant converter 100. Figure 3A to Figure 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 14C and Figure 14D 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.

[0209] See also Figure 14E The 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.

[0210] For reference Figure 14E , and with Figure 11A Taking the traces T_1(n) and T_1(m) forming the modular winding WM as an example, it is assumed that the traces T_1(n) and T_1(m) are embedded in the first sub-layer board LA1. Figure 14E The (a) sub-figure shows a top view of the traces T_1(n) and T_1(m), and the (b) sub-figure shows a cross-sectional view of the traces T_1(n) and T_1(m). The traces T_1(n) to T_3(n) of the first layer (upper layer) of the modular winding WM are arranged in the same extension direction DW_1, and are electrically connected to the traces T_1(n) to T_3(n) of the second layer (lower layer) through a conductive material MC (for example, copper, aluminum, etc., and preferably a columnar structure), and the traces T_1(m) to T_3(m) of the lower layer are also arranged in the same extension direction DW_2, so that the traces T_1 to T_3 extend alternately in the first layer and the second layer through the conductive material MC. In one embodiment, the traces T_1 to T_3 are similar to Figure 8D As mentioned above, the traces T_1 to T_3 on different layers form an acute angle with the conductive material as the center, and the angle of the acute angle is between 25 degrees and 30 degrees, which is a preferred embodiment. Figure 14EWhen 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).

[0211] The first and second layers are similar to Figure 11C The relationship between the sub-layer boards LA1 and LA2 (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.

[0212] For reference Figure 14F The top view and cross-sectional view of the circuit board of the second embodiment of the flat-plate transformer of the present disclosure using the embedded technology are also shown. Figure 11A For example, the wiring T_1(n) and T_1(m) form a modular winding WM. Figure 14F 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.

[0213] See also Figure 14G This is a side view of a circuit board using embedded technology for routing the power components and flat-plate transformers disclosed herein. Figures 14A to 14GUsing 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.

[0214] In this embodiment, the power element 400 and the traces T_1(n), T_1(m), T_2(n), T_2(m) of the modular winding WM are embedded in the same sub-layer board LA, which can effectively shorten the distance between the power element 400 and the traces T_1(n), T_1(m), T_2(n), T_2(m). For example, the power element 400 is the first switch SR1 and is embedded in the same sub-layer board as the first secondary-side trace Ts1 (with Figure 11C For example, the first switch SR1 is electrically connected to the first switch SR1 via electrical trace Tc_1 and pad Pad_1, effectively shortening the distance between the two. Similarly, in other embodiments, the power device 400 and the traces T_1(n), T_1(m), T_2(n), and T_2(m) of the modular winding WM can be embedded in a different sub-layer board LA. Compared to conventional power devices 400 that must be located on the surface of the circuit board CB, the power device 400 of the present disclosure need not be located on the surface of the circuit board CB. Therefore, it can avoid other components and traces on the surface of the circuit board CB, simplifying the complexity of the circuit design.

[0215] See also Figure 15A This is a diagram showing the arrangement of components of the secondary side circuit of the resonant converter disclosed herein. Figures 12A and 12B The secondary side circuit 3A is disposed on the circuit board CB, and the secondary side circuit 3A includes a first switch SR1, a second switch SR2 and an output capacitor Co. Figure 3A to Figure 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).

[0216] exist Figure 15A 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 15A As shown, they are arranged in parallel in the same direction, or as Figure 11A 、 Figure 11B As shown in the (a) sub-figure, they are arranged in pairs opposite to each other. 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 14C ), so Figure 15A The component setting method can provide the shortest current path Li and reduce path loss.

[0217] See also Figure 15B This is a diagram showing the arrangement of components of the resonant converter according to different secondary side circuit structures. Figure 15A . Figure 15B The main structure is a side view of the output terminal OUT of the circuit board CB toward the iron core C1, and the first switch SR1, the second switch SR2 and the output capacitor Co are connected. Figure 3A to Figure 3C Different secondary side circuits 3A may have different configurations, but may also be configured as follows: Figure 15A The current path Li. Figure 15BIn 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 15B 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.

[0218] exist Figure 15B 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 15B 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.

[0219] exist Figure 15B 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 15B 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 15A 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.

[0220] For reference Figures 3A to 15B The resonant converter 100 disclosed herein uses a monolithic circuit board CB that can be selectively combined with litz wire, interleaving winding, embedded technology, component placement, and other technologies according to actual needs to improve the overall circuit efficiency of the resonant converter 100. In one embodiment, Figures 3A to 15B 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 15B 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.

[0221] See also Figure 16A A first perspective view of the three-dimensional circuit structure combination of the second embodiment of the resonant converter disclosed herein, Figure 16B This is a second perspective view of the three-dimensional circuit structure combination of the second embodiment of the resonant converter disclosed in the present invention, and is used in conjunction with Figure 4A . Figure 16A 、 Figure 16B Mainly, the circuit of the resonant converter 100 (for example: Figure 3A to Figure 3CThe circuit diagram (see circuit diagram) is converted into a physical structure consisting of two circuit boards CB1 and CB2. This allows the resonant converter 100, consisting of circuit boards CB1 and CB2, to convert a DC power source Pdc into an output power source Po. In its physical structure, resonant converter 100 includes first and second circuit boards CB1 and CB2, a primary circuit 1A, a secondary circuit 3A, and a planar transformer PE serving as transformer 2A. The first circuit board CB1 comprises multiple sub-layer boards, with an input terminal IN and an output terminal OUT formed on the edge of the first circuit board CB1. The input terminal IN of the first circuit board CB1 receives the DC power source Pdc, and the output terminal OUT provides the output power source Po. The input terminal IN and the output terminal OUT are formed on the edge of the second circuit board CB2, which also provides the output power source Po. The formation of the input terminal IN and the output terminal OUT on the edges of the circuit boards CB1 and CB2 primarily allows the circuit boards CB1 and CB2 to be plugged into any device requiring power conversion, such as a power supply or uninterruptible power supply system. Vertical plugging saves device space.

[0222] The primary side circuit 1A is disposed on the first circuit board CB1 and the second circuit board CB2. The circuit components of the primary side circuit 1A that can be clearly seen on the first circuit board CB1 include the power switches Q1 and Q2 of the primary side switch bridge arm SP_1 and the inductor core CL used to form the resonant inductor Lr. Figure 16B The second circuit board CB2 includes part of the circuitry of the resonant converter 100. Specifically, the first circuit board CB1 includes a portion of the inductor winding Lc of the resonant inductor Lr and a portion of the winding 22 of the transformer 2A, while the second circuit board CB2 includes another portion of the inductor winding Lc and another portion of the winding 22 of the transformer 2A. The iron core C1 nests the first and second circuit boards CB1 and CB2 together to form the transformer 2A of the resonant converter 100.

[0223] For reference Figure 3A to Figure 3C 、 Figures 16A and 16BThe resonant converter 100, constructed on two circuit boards CB1 and CB2, includes two (or more) sets of secondary-side circuits 3A. Thus, the first circuit board CB1 and the second circuit board CB2 can each be provided with a set of secondary-side circuits 3A. The circuit components of the secondary-side circuit 3A, which can be clearly seen on the circuit boards CB1 and CB2, include the first switch SR1 and the second switch SR2 of the rectifier circuit 32, and the output capacitor Co. A planar transformer PE is provided on the first circuit board CB1 and the second circuit board CB2, electrically connecting the primary-side circuit 1A and the secondary-side circuit 3A. The planar transformer PE includes an iron core C1, which forms the planar transformer PE. The resonant inductor Lr and the planar transformer PE are arranged on the circuit boards CB1 and CB2 using traces, enabling a planar structure. This replaces the larger winding-type transformer / inductor used, thereby reducing the volume occupied by the resonant converter 100. The system control circuit MCU (including the controller 4A for controlling the resonant converter 100 ) may be disposed on the first circuit board CB1 or the second circuit board CB2 , and the system control circuit MCU may communicate with external devices via the signal transmission terminal SG disposed on the first circuit board CB1 or the second circuit board CB2 .

[0224] See also Figure 16C This is a third perspective view of the three-dimensional circuit structure combination of the second embodiment of the resonant converter disclosed in the present invention. Figure 3A to Figure 3C 、 Figures 16A and 16B The flat transformer PE further includes a conductive post PC_1, which is disposed between the first circuit board CB1 and the second circuit board CB2. Since the first circuit board CB1 includes a portion of the transformer 2A winding 22 formed by traces, and the second circuit board CB2 includes another portion of the transformer 2A winding 22 formed by traces, these portions of the winding 22 can be electrically connected together via the conductive post PC_1 to form a complete winding 22A. Figure 16D This is a three-dimensional circuit structure decomposition diagram of the second embodiment of the resonant converter disclosed herein, which mainly decomposes the inductor core CL of the resonant inductor Lr and the core C1 of the transformer 2A. The flat transformer PE also includes a first circuit board through-hole CB1_H, a second circuit board through-hole CB2_H, a primary side winding 22A and a secondary side winding 22B.

[0225] The first circuit board through-hole CB1_H includes a first through-hole H1 and a second through-hole H2, each extending through the first circuit board CB1. The second circuit board through-hole CB2_H includes a third through-hole H3 and a fourth through-hole H4, each extending through the second circuit board CB2. The primary winding 22A and the secondary winding 22B respectively surround the first through-hole H1 and the second through-hole H2 of the first circuit board through-hole CB1_H, and the third through-hole H3 and the fourth through-hole H4 of the second circuit board through-hole CB2_H. In other words, the primary winding 22A and the secondary winding 22B are formed in a routing structure on the sub-layers of the first circuit board CB1 and the second circuit board CB2, respectively, and surround the first circuit board through-hole CB1_H and the second circuit board CB2. The primary winding 22A and the secondary winding 22B are encased in the core C1 to form a flat-plate transformer PE.

[0226] 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 part of the winding 22 of the first circuit board CB1 and another part of the winding 22 of the second circuit board CB2. 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.

[0227] If Figures 3A to 3C Circuit implementation Figures 16A to 16D In this circuit structure, since the primary-side windings 22A of the resonant converter 100 are connected in series, a portion of the primary-side windings 22A on the first circuit board CB1 and another portion of the primary-side windings 22A on the second circuit board CB2 can be electrically connected via conductive posts PC_1 to form a complete primary-side winding 22A. Since the secondary side of the resonant converter 100 includes two sets of secondary-side circuits 3A, each with parallel outputs, the first circuit board CB1 and the second circuit board CB2 can each be provided with a set of secondary-side windings 22B. Since the secondary side of the transformer 2A is a parallel structure, the secondary-side windings 22B of the first circuit board CB1 and the second circuit board CB2 do not require conductive posts for electrical connection; they can be electrically connected to each other simply by connecting their respective output terminals OUT in parallel.

[0228] The flat-plate transformer PE is covered by two covers C1_1 and C1_2, so that the first core leg C12 extends through the first through-hole H1 of the first circuit board through-hole CB1_H and the third through-hole H3 of the second circuit board through-hole CB2_H, and the second core leg C14 extends through the second through-hole H2 of the second circuit board through-hole CB2_H and the fourth through-hole H4 of the second circuit board through-hole CB2_H. Thus, the first circuit board CB1 and the second circuit board CB2 can be nested together by the two covers C1_1 and C1_2 to form the transformer 2A of the resonant converter 100. See also Figures 16A to 16C The side portion C1_3 located outside the first and second circuit boards CB1 and CB2 forms an air gap GP. This air gap GP is formed outside the first and second circuit boards CB1 and CB2, making it easy to adjust the size of the air gap GP and thereby adjust the magnetic resistance of the planar transformer PE, thereby preventing magnetic saturation during circuit operation. Because the air gap GP is located between the first and second circuit boards CB1 and CB2, the magnetic flux lines generated around the air gap GP are less likely to intersect the primary winding 22A and the secondary winding 22B. This creates an air gap avoidance effect, reducing heat loss in the windings and improving efficiency.

[0229] In this embodiment, the core C1 includes two core legs C12 and C14, which extend through the first circuit board through-hole CB1_H (i.e., the first through-hole H1 and the second through-hole H2) and the second circuit board through-hole CB2_H (i.e., the third through-hole H3 and the fourth through-hole H4) of the first circuit board CB1 and the second circuit board CB2, respectively. In other embodiments, for example, the first circuit board CB1 and the second circuit board CB2 may include only a single through-hole (i.e., the first circuit board through-hole CB1_H includes only the first through-hole H1, and the second circuit board CB2 includes only the third through-hole H3), with the winding 22 wrapped around this single through-hole. Furthermore, the single core leg C12 of the core C1 extends through the first through-hole H1 and the third through-hole H3, thereby forming a flat-plate transformer PE. The conductive pillar PC_1 also electrically connects the primary-side traces disposed around the first circuit board through-hole CB1_H and the primary-side traces disposed around the second circuit board through-hole CB2_H to form a primary-side winding 22A. The secondary-side traces can form a secondary-side winding 22B without the use of a conductive pillar for electrical connection, and the sum total becomes the winding 22 of the flat-plate transformer PE.

[0230] For reference Figures 16A to 16DThe resonant converter 100 further includes an inductor through-hole HL and an inductor winding Lc. The inductor through-hole HL includes a first inductor through-hole HL1 formed on the first circuit board CB1 and a second inductor through-hole HL2 formed on the second circuit board CB2, with the first inductor through-hole HL1 and the second inductor through-hole HL2 respectively extending through the first circuit board CB1 and the second circuit board CB2. The inductor winding Lc is electrically connected to the winding 22 and surrounds the inductor through-hole HL. Similar to the winding 22 of the transformer 2A, the inductor winding Lc is formed in a routing structure on the sub-layers of the first circuit board CB1 and the second circuit board CB2, respectively. The first circuit board CB1 may include a portion of the inductor winding Lc, and the second circuit board CB2 may include another portion of the inductor winding Lc. The flat-plate transformer PE further includes a conductive post PC_2, which is also disposed between the first circuit board CB1 and the second circuit board CB2. Because the first circuit board CB1 includes a portion of the inductor winding Lc, and the second circuit board CB2 includes another portion of the inductor winding Lc, these portions of the inductor winding Lc can be electrically connected together via the conductive pillar PC_2 to form a complete inductor winding Lc. The inductor core CL nests the inductor windings Lc of the first and second circuit boards CB1 and CB2 together to form the resonant inductor Lr of the resonant converter 100.

[0231] In this embodiment, the inductor core CL can be a core of a UI, UU, or other type. The inductor core CL includes two covers CL_1 and CL_2, each of which includes a main body. At least one of the 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 side portions CL_3 extends through an 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. The receiving groove CL_4 is used to accommodate a portion of the inductor winding Lc on the first circuit board CB1 and another portion of the inductor winding Lc on the second circuit board CB2. Portions of the side portions C1_3 of the two covers CL_1 and CL_2 are located outside the circuit boards CB. In this embodiment, the side portions C1_3 located outside the first and second circuit boards CB1 and CB2 form an air gap GP, which functions similarly to the air gap GP of the core C1.

[0232] In one embodiment, the conductive pillars PC_1 and PC_2 are, for example, copper pillars, aluminum pillars, or other pillars having a conductive function. In another embodiment, the resonant converter 100 of the present disclosure may include, in addition to the conductive pillars PC_1 and PC_2, a plurality of pillars PC (e.g., Figure 16D(As shown). The various pillars PC can be made of suitable materials based on their functions. For example, some pillars PC, like conductive pillars PC_1 and PC_2, can have conductive properties to guide current flow and serve as supports for the first and second circuit boards CB1 and CB2, while other pillars PC can be made of non-conductive materials and serve solely as supports.

[0233] like Figures 16A to 16D As shown, the first circuit board CB1 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 a 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 first circuit board CB1, and the transformer 2B is formed by being sheathed through the iron core C2. The iron core C2 can also correspond to the iron core C1, forming 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 16A 、 Figure 16B 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.

[0234] For reference Figure 17A is a wiring structure diagram of one surface layer of the first circuit board of the second embodiment, and Figure 17BThis is a wiring diagram of another surface layer of the first circuit board of the second 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. Based on the above-described path, the high-current path (referred to as the power path) of the first circuit board CB1 from the input terminal IN to the output terminal OUT forms an n-type path 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.

[0235] exist Figure 17B In the figure, the other side opposite the location of the control circuit MCU includes a DC / DC converter circuit, which is mainly 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, drivers, etc. on the first circuit board CB1 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, it is possible to convert the power into a suitable voltage 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 the power switches Q1 and Q2 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.

[0236] For reference Figure 18A is a wiring structure diagram of one surface layer of the second circuit board of the second embodiment, and Figure 18BThis is a wiring structure diagram of another surface layer of the second circuit board of the second embodiment. The second circuit board CB2 may optionally include a signal transmission terminal SG, so that the second circuit board CB2 can communicate with an external device directly through the signal transmission terminal SG without transmitting the signal back to the first circuit board CB1. The second circuit board CB2 can be electrically connected to the first circuit board CB1 through the conductive columns PC_1 and PC_2 to receive the DC power supply Pdc. In one embodiment, the second circuit board CB2 is not provided with an auxiliary power circuit AUX, so the second circuit board CB2 can save space for providing the auxiliary power circuit AUX, making the board length of the second circuit board CB2 shorter than that of the first circuit board CB1 (see Figures 16A to 16D ).

[0237] For reference Figure 18B The second circuit board CB2 may also include a system control circuit MCU or a DC / DC converter circuit on both sides. The DC / DC converter circuit may consist of at least one small step-down converter. Its functions are similar to those of the system control circuit MCU and DC / DC converter circuit on the first circuit board CB1, primarily enabling communication with external devices via the signal transmission port SG or converting voltages to power certain controllers, drivers, and other components on the second circuit board CB2. Because the resonant converter 100 utilizes a four-sided physical structure with two circuit boards CB1 and CB2, it can evenly distribute heat, effectively increasing the heat dissipation area. The resonant converter 100 also utilizes the distributed arrangement of the windings 22 of the resonant converter 100 across the two circuit boards CB1 and CB2, thereby reducing heat generation and improving circuit efficiency. Because the resonant converter 100 utilizes a primary-side series and secondary-side parallel configuration, the first switch SR1 and the second switch SR2 of the secondary-side circuit 3A can be distributed across the circuit boards CB1 and CB2, providing improved heat dissipation.

[0238] See also Figures 19A to 19H Schematic diagrams of the wiring of the windings of the flat-plate transformer of the present disclosure on the first circuit board of the second embodiment on each sub-layer board. In this embodiment, the first circuit board CB1 is taken as an example with 8 layers of sub-layer boards LA1-1 to LA1-8, and the sub-layer boards LA1-1 to LA1-8 are sequentially from the top board to the bottom board. In other embodiments, the number of layers of the first circuit board CB1 can be increased or decreased according to actual circuit requirements. Figure 3A to Figure 3CAmong the traces on sub-layer boards LA1-1 to LA1-8, inductor trace Tl-1 serves as the resonant inductor Lr, and is provided in the inductor winding Lc (i.e., part of the inductor winding Lc) on the first circuit board CB1. Primary-side trace Tp-1 serves as the primary-side winding 22A (i.e., part of the primary-side winding 22A) on the first circuit board CB1 of transformer 2A. Secondary-side trace Ts-1 serves as the secondary-side winding 22B on the first circuit board CB1 of transformer 2A, and secondary-side trace Ts-1 includes a first secondary-side trace Ts1-1 and a second secondary-side trace Ts2-1. First secondary-side trace Ts1-1 serves as the first winding 22B-1 on the first circuit board CB1, and second secondary-side trace Ts2-1 serves as the second winding 22B-2 on the first circuit board CB1.

[0239] In this embodiment, the copper foil of the primary-side trace Tp-1 and the copper foil of the inductor trace Tl-1 are integrally formed to form a common routing structure. The primary-side trace Tp-1 and the secondary-side trace Ts-1 are located on different sub-layers LA1-LA8 to ensure even current distribution when the current flows through the sub-layers LA1-1-LA1-8. In other embodiments, the inductor trace Tl-1, the primary-side trace Tp-1, and the secondary-side trace Ts-1 can be located on the same sub-layers LA1-1-LA1-8 depending on actual circuit requirements. The primary-side trace Tp-1 and the secondary-side trace Ts-1 are respectively formed and wrapped around the first through-hole H1 and the second through-hole H2 of the first circuit board through-hole CB1_H, and the inductor trace Tl is formed and wrapped around the inductor through-hole HL.

[0240] See also Figures 20A to 20H The following are schematic diagrams of the wiring of the windings of the flat-plate transformer of the present disclosure on the second circuit board of the second embodiment on each sub-layer board. In this embodiment, the second circuit board CB2 takes 8 layers of sub-layer boards LA2-1 to LA2-8 as an example (top board to bottom board in order), and the number of layers of sub-layer boards LA2-1 to LA2-8 of the second circuit board CB2 is the same as that of the first circuit board CB1 to make the current average, which is a preferred embodiment. In other embodiments, the number of layers of the second circuit board CB2 can also be increased or decreased according to actual circuit requirements. Figure 3A to Figure 3C 、 Figures 20A to 20HAmong the traces on the sub-layer boards LA2-1 to LA2-8, the structures and functions of the first secondary trace Ts1-2 and the second secondary trace Ts2-2 of the inductor trace Tl-2, the primary trace Tp-2, and the secondary trace Ts-2 are similar to those of the corresponding traces on the first circuit board CB1. The difference is that the positions of the first secondary trace Ts1-2 and the second secondary trace Ts2-2 are swapped. The purpose of swapping the positions of the first secondary trace Ts1-2 and the second secondary trace Ts2-2 is to allow the current of the secondary circuit 3A to be evenly distributed during operation, rather than being concentrated on the two adjacent sub-layer boards. That is, if the current of the secondary circuit 3A is Figure 19H and Figure 20A Both are first secondary-side traces Ts1 - 1 and Ts1 - 2 , and when the first switch SR1 is turned on, these two layers are more adjacent and therefore less likely to evenly distribute the current.

[0241] For reference Figures 19A to 20H The primary-side trace Tp-1 of the first circuit board CB1 is electrically connected to the primary-side trace Tp-2 of the second circuit board CB2 via a conductive post PC_1, forming a primary-side series connection. The iron core C1 is sheathed around the primary-side trace Tp-1, primary-side trace Tp-2, and secondary-side traces Ts-1 and Ts-2, forming a closed magnetic circuit and forming transformer 2A. The inductor trace Tl-1 of the first circuit board CB1 is electrically connected to the inductor trace Tl-2 of the second circuit board CB2 via a conductive post PC_2. The inductor core CL is sheathed around the inductor traces Tl-1 and Tl-2, forming a closed magnetic circuit and forming the resonant inductor Lr. In one embodiment, the primary-side circuit 1A is disposed on the first circuit board CB1 and the second circuit board CB2 mainly because the circuit boards CB1 and CB2 each have inductor traces Tl-1 and Tl-2. However, the inductor traces Tl-1 and Tl-2 can also be both disposed on the first circuit board CB1 and then electrically connected to the primary-side winding 22A of the first circuit board CB1 or electrically connected to the primary-side winding 22A through conductive pillars PC_1, PC_2, and pillar PC. Therefore, the primary-side circuit 1A can be disposed only on the first circuit board CB1.

[0242] exist Figures 19C to 19FIn the corresponding diagrams 20C-20F, primary-side traces Tp-1 and Tp-2 each wrap around the first PCB through-hole CB1_H and the first PCB through-hole CB2_H at least once (depending on the turns ratio of transformer 2A) in different directions, forming a ∞-shaped trace. Multiple vias Via_A are formed on one side of the first through-hole H1 and second through-hole H2 of the first PCB through-hole CB1_H, and on one side of the third through-hole H3 and fourth through-hole H4 of the second PCB through-hole CB2_H. The vias Via_A are located at the tail ends of the primary side traces Tp-1 and Tp-2, and the inside of the vias Via_A is filled with conductive material (for example, but not limited to, conductive materials such as solder cake), so that the primary side traces Tp-1 and Tp-2 of each sub-layer board LA1-3 to LA1-6, LA2-3 to LA2-6 can be electrically connected through the vias Via_A, and the two primary side traces Tp-1 and Tp-2 are electrically connected through the conductive column PC_1 to form a primary side winding 22A.

[0243] exist Figures 19A and 19B 、 Figures 19G to 19H In the embodiment, the secondary-side trace Ts-1 forms an M-shaped trace with the first through-hole H1 and the second through-hole H2 of the first circuit board CB1. 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-1 formed and encircling the first through-hole H1 flows in the same direction as the secondary-side trace Ts-1 (e.g., clockwise). The current in the primary-side trace Tp-1 formed and encircling the second through-hole H2 flows in the opposite direction 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-1. The vias Via_B are filled with conductive material. This allows the secondary-side traces Ts-1 on the sub-layers LA1-1, LA1-2, LA1-7, and LA1-8 to be electrically connected via the vias Via_B to form a secondary-side winding 22B. Figures 20A and 20B 、 Figures 20G to 20H The secondary-side trace Ts-2 can be electrically connected to the secondary-side trace Ts-1 through the via Via_B to form another secondary-side winding 22B.

[0244] exist Figure 19F 、 Figure 20FIn the embodiment, the inductor trace Tl-1 is formed and surrounds the first inductor through-hole HL1, and the inductor trace Tl-2 is formed and surrounds the second inductor through-hole HL2. In this embodiment, the copper foil of the inductor trace Tl-1 and the primary side trace Tp-1 are an integrally formed structure, and the copper foil of the inductor trace Tl-2 and the primary side trace Tp-2 are an integrally formed structure, so a part of the integrally formed copper foil belongs to the inductor trace Tl-1, and the other part belongs to the primary side trace Tp-1 (the same is true for the inductor trace Tl-2). In other embodiments, the inductor trace Tl-1 and the primary side trace Tp-1 can be set separately (the same is true for the inductor trace Tl-2 and the primary side trace Tp-2), for example, other circuit elements such as a resonant capacitor Cr can be included between the two. In this embodiment, the inductor trace Tl-1, the primary side trace Tp-1 and the secondary side trace Ts-1 are not limited to being arranged in a certain manner. Figure 18A~1 8H (the same applies to the inductor trace Tl-2, the primary-side trace Tp-2, and the secondary-side trace Ts-2). The first and second sub-layer boards described later are not the stacking order, but only represent a sub-layer board LA1-1 and another sub-layer board LA1-8 in the first circuit board CB1.

[0245] For reference Figure 21A For this disclosure Figures 19A to 19H FIG1 is a diagram showing a planar transformer with a stacked structure of traces on each sub-layer of the first circuit board of the second embodiment, and a magnetomotive force curve when the first circuit board is operating on the first secondary side traces. Figure 21A From top to bottom on the left: Figures 19A to 19H The routing stacking structure diagram, and Figure 21A The right side corresponds to Figure 21A The magnetomotive force curve formed by the stacked trace structure on the left. In this embodiment, sub-layers LA1-1 to LA1-2, LA1-7 to LA1-8 form a loop of first secondary-side trace Ts1-1 or second secondary-side trace Ts2-1 centered around through-holes H1 and H2, and sub-layers LA3 to LA6 form a loop of primary-side trace Tp-1 centered around through-holes H1 and H2. The spacing between each trace can be considered the thickness between each sub-layer LA1-1 to LA1-8. In one embodiment, because the first circuit board CB1 has sufficient board space, the insulation layer between the primary and secondary layers (i.e., between sub-layers LA1-2 and LA1-3, and between sub-layers LA1-6 and LA1-7) can be thickened to reduce parasitic capacitance, thereby optimizing dead time and improving efficiency and electromagnetic interference. The horizontal axis of the magnetomotive force graph is magnetomotive force (MMF), and the vertical axis is 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 a first predetermined offset M1 and a second predetermined offset Mr.

[0246] 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. During actual operation of the transformer 2A, although the actual offsets 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 formation of the primary-side trace Tp-1 enables the primary-side trace Tp-1 to generate a first-directional magnetic flux F_D1 during operation of the primary-side circuit 1A. The formation of the first secondary-side trace Ts1-1 enables the first switch SR1 of the secondary-side circuit 3A of the first circuit board CB1 to generate a second-directional magnetic flux F_D2 opposite to the first-directional magnetic flux F_D1 during operation of the first switch SR1.

[0247] When the primary-side trace Tp-1 generates a first-directional magnetic flux F_D1, causing a magnetic flux offset, the second-directional magnetic flux F_D2 generated by the first secondary-side trace Ts1-1 offsets the magnetomotive force MMF in the opposite direction to maintain the first-directional magnetic flux F_D1 and the second-directional 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. When the flat-plate transformer 2A operates, the magnetomotive force curve CF1 of the first circuit board CB1 is maintained within the specific range Rm, thereby maintaining a balanced magnetomotive force MMF.

[0248] Since only the first switch SR1 or the second switch SR2 operates in the same half-cycle in the center-tap structure of the first winding 22B-1, when the first switch SR1 is on and the second switch SR2 is off, no current path is formed between the second winding 22B-2 and the rectifier switch SR2, causing the magnetomotive force MMF of the second secondary-side trace Ts2-1 to not shift toward the first predetermined offset M1 or the second predetermined offset Mr. Based on the above logic, the magnetomotive force curve when the first switch SR1 is off and the second switch SR2 is on can be inferred, which will not be further described here. Figure 21B For this disclosure Figures 20A to 20H The trace stacking structure of each sub-layer of the second circuit board of the second embodiment of the planar transformer is combined with the magnetomotive force curve of the second circuit board during operation of the first secondary-side traces. Because the trace stacking structure of each layer of the second circuit board CB2 is identical to that of the first circuit board CB1, the trace stacking structure of the second circuit board CB2 can also maintain the first-direction magnetic flux F_D1 and the second-direction magnetic flux F_D2 within the specific range Rm defined by the magnetic flux origin M0 and the first and second predetermined offsets M1 and Mr. This maintains the magnetomotive force curve CF2 of the second circuit board CB2 within the specific range Rm during operation of the planar transformer 2A, thereby maintaining a balanced magnetomotive force MMF.

[0249] because Figure 4A 、 Figure 4B and Figure 16A 、 Figure 16B The circuit of the resonant converter 100 is also converted into a physical structure. The main difference is Figure 4A 、 Figure 4B It is a single-chip circuit board CB type physical structure. Figure 16A 、 Figure 16B It is a physical structure of two circuit boards CB1 and CB2. Therefore, it can be applied to the litz wire, interleaving winding, embedded technology, component setting and other technologies of the single circuit board CB (i.e. Figures 8A to 14B ) can also be applied to Figure 16A 、 Figure 16B The physical structure of two circuit boards CB1 and CB2.

[0250] For reference Figures 8A to 11C 、 Figure 16A 、 Figure 16B In the technology of using litz wire in a physical structure with two circuit boards CB1 and CB2, the inductor trace Tl-1, primary trace Tp-1, and secondary trace Ts-1 of circuit board CB1 can be intertwined with multiple insulated wires, and the inductor trace Tl-2, primary trace Tp-2, and secondary trace Ts-2 of circuit board CB2 can also be intertwined with multiple insulated wires to effectively reduce AC impedance. Figures 12A to 13 、 Figure 16A 、 Figure 16B In the interleaving winding technology with a physical structure of two circuit boards CB1 and CB2, the first secondary-side trace Ts1-1 and the second secondary-side trace Ts2-1 in the secondary-side trace Ts-1 of the circuit board CB1 can use a circular interleaving winding structure, and the first secondary-side trace Ts1-2 and the second secondary-side trace Ts2-2 in the secondary-side trace Ts-2 of the circuit board CB2 can also use a circular interleaving winding structure to achieve the effect of magnetic flux cancellation.

[0251] In the physical structure of two circuit boards CB1 and CB2 Figure 8BAmong the characteristics of litz wire, the first circuit board CB1 includes multiple vias (Via_C) around the perimeter of the winding area and around the through-hole H1. These vias electrically connect the first sub-layer LA1 and the second sub-layer LA2. The second circuit board CB2 also includes multiple vias (Via_C) around the perimeter of the winding area and around the through-hole H3. These vias also electrically connect the first sub-layer LA1 and the second sub-layer LA2. Traces T_1-T_3 on the first circuit board CB1 can extend alternately between the first sub-layer LA1 and the second sub-layer LA2 via these vias (Via_C) provided on the first circuit board CB1. Similarly, traces T_1-T_3 on the second circuit board CB2 can extend alternately between the first sub-layer LA1 and the second sub-layer LA2 via these vias (Via_C) provided on the second circuit board CB2. When the entire winding area is filled, the traces T_1 to T_3 on the same layer are arranged in parallel, and the traces T_1(n) to T_3(n) on the first sub-layer board LA1 can be arranged in an overlapping and staggered manner with the traces T_1(m) to T_3(m) on the second sub-layer board LA2.

[0252] In the physical structure of two circuit boards CB1 and CB2 Figure 11B In the features of the first circuit board CB1, the sub-layer boards LA1 and LA2 are layers for setting the secondary-side winding 22B. Therefore, the traces T_1 to T_n are multiple secondary-side traces Ts-1_1 to Ts-1_n, which are used to electrically connect the secondary-side winding 22B of one of the secondary-side circuits 3A. The sub-layer boards LA1 and LA2 of the second circuit board CB2 are also layers for setting the secondary-side winding 22B. Therefore, the traces T_1 to T_n are also multiple secondary-side traces Ts-2_1 to Ts-2_n, which are used to electrically connect the secondary-side winding 22B of the other secondary-side circuit 3A. Figures 19A and 19B 、 Figures 19G to 19H 、 Figures 20A and 20B 、 Figures 20G to 20H , Figure 11B The staggered secondary side traces Ts_1 to Ts_n can replace the first secondary side traces Ts1-1, Ts1-2 or the second secondary side traces Ts2-1, Ts2-2, and apply Figures 8A to 10D The angle θ, line width and line spacing are set by the technology, and Figures 19C to 19F , 20C ~ 20F primary side routing Tp-1, Tp-2 can be selected to apply or not Figures 8A to 10D 、 Figures 11A and 11B The staggered routing setting technology can be set according to the level of AC impedance AC_R and the uniformity of magnetic flux.

[0253] In the physical structure of two circuit boards CB1 and CB2 Figure 12A 、 Figure 12B In the interleaving winding feature, the flat-type transformer PE includes two first vias (Via_E), two second vias (Via_F), two third vias (Via_G), and two fourth vias (Via_H). One of the first vias (Via_E) and the second via (Via_F) is formed on a first side and a second side opposite the first side of the first through-hole (H1), respectively. The first vias (Via_E) and the second vias (Via_F) are used to electrically connect the first sub-layer LA1 and the second sub-layer LA2 of the first circuit board CB1. One of the third vias (Via_G) and the fourth vias (Via_H) is formed on a first side and a second side opposite the first side of the first through-hole (H1), respectively. The third vias (Via_G) and the fourth vias (Via_H) are used to electrically connect the first sub-layer LA1 and the second sub-layer LA2 of the first circuit board CB1. Another first via Via_E, a second via Via_F, a third via Via_G, and a fourth via Via_H are disposed on the second circuit board CB2 at the same location as the first circuit board CB2. In this embodiment, the second side is located near the output terminal OUT, while the first side is located on the other side of the first through-hole H1. The first switch SR1, the second switch SR2, and the output capacitor Co are disposed on the second side.

[0254] For the physical structure of the two circuit boards CB1 and CB2, refer to Figure 12A As shown in sub-figure (a), the first secondary trace Ts1-1_(n) of the first circuit board CB1 can be located on the first sub-layer LA1 and electrically connected to the first switch SR1. The first secondary trace Ts1-1_(n) extends from the first sub-layer LA1 in a first direction D1 surrounding the first through-hole H1 to the first via Via_E, and then extends through the first via Via_E to the second sub-layer LA2. Figure 12A As shown in the sub-figure (b), the first secondary-side trace Ts1-1_(m) extending to the second sub-layer board LA2 continues the first direction D1 and extends to the second side to be electrically connected to the output capacitor Co through the second via Via_F.

[0255] The second secondary trace Ts2-1_(n) of the first circuit board CB1 can be located on the first sub-layer LA1 and electrically connected to the second switch SR2. The second secondary trace Ts2-1_(n) extends from the first sub-layer LA1 in the second direction D2, surrounding the first through-hole H1, to the third via Via_G, and then extends to the second sub-layer LA2 through the third via Via_G. The second secondary trace Ts2-1_(m) extending to the second sub-layer LA2 continues in the second direction D2 to the second side, and is electrically connected to the output capacitor Co through the fourth via Via_H. Figure 12AIn panels (a) and (b), the first switch SR1 and the second switch SR2 are respectively arranged on opposite sides of the second via Via_F (fourth via Via_H), and the first direction D1 and the second direction D2 are in opposite directions along the first through-hole H1 to form a ring-shaped staggered routing structure.

[0256] For reference Figure 12B The first via Via_E and the second via Via_F are respectively formed on the third side and the fourth side opposite to the third side of the second through hole H2 of the first circuit board CB1, and the first via Via_E and the second via Via_F are used to electrically connect the first sub-layer board LA1 and the second sub-layer board LA2 of the first circuit board CB1. Figure 12A The first side may be the same side, and the fourth side and the second side may be the same side, the only difference being that the positions of the first through hole H1 and the second through hole H2 are different.

[0257] For reference Figure 12B As shown in panels (a) and (b) of FIG1 , a first secondary-side trace Ts1-1_(n) of the first circuit board CB1 extends from the first sub-layer LA1 in the second direction D2, surrounding the second through-hole H2, to the first via Via_E, and then extends to the second sub-layer LA2 through the first via Via_E. The first secondary-side trace Ts1_(m) extending to the second sub-layer LA2 continues in the second direction D2 to the fourth side, and is electrically connected to the output capacitor Co through the second via Via_F. A second secondary-side trace Ts2-1_(n) of the first circuit board CB1 extends from the first sub-layer LA1 in the first direction D1, surrounding the second through-hole H2, to the third via Via_G, and then extends to the second sub-layer LA2 through the third via Via_G. The second secondary-side trace Ts2_(m) extending to the second sub-layer LA2 continues in the first direction D1 to the fourth side, and is electrically connected to the output capacitor Co through the fourth via Via_H. Figure 12B and Figure 12A Another difference is that the first secondary traces Ts1-1_(n), Ts1-1_(m) and the second secondary traces Ts2-1_(n), Ts2-1_(m) of the first circuit board CB1 are located at opposite positions on the left and right, and extend in opposite directions.

[0258] The second circuit board CB2 is configured similarly to the first circuit board CB1, that is, the first secondary side trace Ts1-2 and the second secondary side trace Ts2-2 are respectively arranged along the third perforation H3 in opposite directions of the first direction D1 and the second direction D2, and the first secondary side trace Ts1-2 and the second secondary side trace Ts2-2 are respectively arranged along the fourth perforation H4 in opposite directions of the first direction D1 and the second direction D2 to form a circular staggered trace structure.

[0259] For reference Figure 13 ,exist Figures 19A and 19B 、 Figures 19G to 19H In the example, since the secondary side trace Ts-1 of the first circuit board CB1 forms an M-shaped trace with the first through hole H1 and the second through hole H2, the Figure 12A 、 Figure 12B The staggered laying of the wiring extension is integrated together to form Figure 13 As shown in Figure 13(a), when the two sides of the m-shaped trace are the first secondary traces Ts1-1_(n), Figure 12A 、 Figure 12B The two sets of second secondary side traces Ts2-1_(n) in the first direction D1 and the second direction D2 can be sandwiched between the first secondary side traces Ts1-1_(n). Figure 12A 、 Figure 12B The two sets of second-secondary side traces Ts2-1_(n) have the same properties, so they can be integrated into an integrated configuration. As shown in the small figure 13(b), when the two sides of the M-shaped trace are the second-secondary side traces Ts2-1_(n), Figure 12A 、 Figure 12B The two sets of first secondary-side traces Ts1-1_(n) in the first direction D1 and the second direction D2 can be sandwiched between the second secondary-side traces Ts2-1_(n), thereby also being integrated into a single piece. The second circuit board CB2 has the same characteristics as the first circuit board CB1 and can similarly integrate traces of the same properties into a single piece.

[0260] In one embodiment, Figures 19A to 19H 、 Figures 20A to 20H Can be coated Figures 11A to 11C The structure of the staggered routing is Figures 12A to 13 In combination with the structure of staggered routing, the two circuit boards CB1 and CB2 need to use four sub-layer boards LA1, LA2, LA3, and LA4 respectively, and an additional layer is added to set the primary side routing Tp and the secondary side routing Ts, but the sub-layer board with staggered routing is not applied, for example: LA5.

[0261] For reference Figures 14A to 14F 、 Figure 16A 、 Figure 16BIn a physical structure with two circuit boards CB1 and CB2 and using embedded technology, the inductor winding Lc, winding 22, or power element 400 can be embedded in circuit boards CB1 and CB2. On the first circuit board CB1, the power element 400, a portion of the inductor winding Lc, a portion of the primary winding 22A, and the secondary winding 22B of the first circuit board CB1 can be embedded in circuit board CB1. On the second circuit board CB2, the power element 400, another portion of the inductor winding Lc, another portion of the primary winding 22A, and the secondary winding 22B of the second circuit board CB2 can be embedded in the second circuit board CB2. This simplifies the complexity of the circuit design and minimizes the AC impedance AC_R of circuit boards CB1 and CB2, thereby improving circuit efficiency.

[0262] For the physical structure of the two circuit boards CB1 and CB2, refer to Figure 14A As shown, the power element 400 (for example: 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, SR2 to conduct) can be embedded into any sub-layer LA1~LA8 (illustrated by sub-layer LA1) of the two circuit boards CB1, CB2 using embedded technology. Then, vias Via_D are formed on the circuit boards CB1, CB2 to generate contact Pads on the surface, so that the power element 400 can be electrically connected to the contact Pads through the vias Via_D, for example: electronic components Ce (for example: capacitors, resistors, etc.), any traces T_1(n), T_1(m), T_2(n), T_2(m) of the winding 22, electrical traces Tc for electrically connecting to the electronic component Ce, and other components. Please refer to Figure 14B , electronic components Ce (eg, capacitors, resistors, switches) or electrical traces Tc can be electrically connected to the power element 400 by soldering to the contact pads Pad.

[0263] For the physical structure of the two circuit boards CB1 and CB2, refer to Figure 14C The two circuit boards CB1 and CB2 each include a set of secondary-side circuits 3A and a set of secondary-side traces Ts-1, and the secondary-side traces Ts-1 serve as a set of secondary-side windings 22B (i.e., the resonant converter 100 includes two sets of secondary-side windings 22B and two sets of secondary-side circuits 3A). The secondary-side power components 400 of the first circuit board CB1 (e.g., a first switch SR1, a second switch SR2, a controller IC_SR for controlling the first switch SR1 and the second switch SR2, an output capacitor Co, etc., and the output capacitor Co electrically connects the first switch SR1 and the second switch SR2 to form the secondary-side circuit 3A) can be applied as follows: Figures 14A and 14BThe embedded technology shown is used to embed any sub-layer board of the first circuit board CB1 (for example, embedded in the surface boards LA1 and LA8 of the first circuit board CB1), and then by melting copper into the preset vias Via_D, contact pads are generated on the surface of the sub-layer boards LA1 and LA8. As a result, the first circuit board CB1 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 side winding 22B of the first circuit board CB1 through the corresponding multiple vias Via_D. In one embodiment, the power components 400 on the secondary side of the first circuit board CB1 are set in the first circuit board through-hole CB1_H (see Figures 11A to 11C The first circuit board through-hole CB1_H can 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 opposite sides of the output capacitor Co. The sub-layer boards LA1 and LA8 are provided with a first secondary-side trace Ts1-1, and the sub-layer boards LA2 and LA7 are provided with a second secondary-side trace Ts2-1. The second circuit board CB2 is configured similarly to the first circuit board CB1. The power element 400 can be electrically connected to the secondary winding 22B of the second circuit board CB2 through a corresponding plurality of vias Via_D. The power element 400 is disposed on one side of the second circuit board through-hole CB2_H.

[0264] For the physical structure of the two circuit boards CB1 and CB2, refer to Figure 14C , the embedded technology can also be applied to the primary side of the resonant converter 100. Figure 3A to Figure 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 14C The embedding technology is used to embed the circuit board in any sub-layer of the first circuit board CB1 , 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.

[0265] For the physical structure of the two circuit boards CB1 and CB2, refer to Figure 14DThe inductor winding Lc of the resonant inductor Lr and the winding 22 of the planar transformer PE can also be embedded using embedding technology into any of the sub-layer boards LA1-LA8 (shown as sub-layer LA1) within the circuit boards CB1 and CB2. Each of the two circuit boards CB1 and CB2 includes a set of inductor traces Tl-1 and Tl-2, a set of primary-side traces Tp-1 and Tp-2, and a set of secondary-side traces Ts-1 and Ts-2. The inductor traces Tl-1 and Tl-2 are electrically connected via a conductive post PC_2 to form the inductor winding Lc, and the primary-side traces Tp-1 and Tp-2 are electrically connected via a conductive post PC_1 to form a primary-side winding 22A. The primary-side winding 22A and the secondary-side windings Ts-1 and Ts-2 form a secondary-side winding 22B, which together constitute the winding 22 of the planar transformer PE. 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. Modular winding WM can also be embedded within any sub-layer of circuit boards CB1 or CB2 using this embedding technology. 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 a conductive material MC (e.g., copper, aluminum, etc., preferably a cylindrical structure). Traces T_1(m)-T_3(m) on the lower layer are also arranged in the same extension direction DW_2, allowing traces T_1-T_3 to extend across the first and second layers in an alternating pattern through the conductive material MC. The traces T_1 to T_3 on different layers form an acute angle with the conductive material as the center, and it is a preferred embodiment that the acute angle is between 25 degrees and 30 degrees.

[0266] For the physical structure of the two circuit boards CB1 and CB2, refer to Figure 14D When the embedding technology is applied to the inductor winding Lc and winding 22 of the resonant converter 100, the modular inductor winding Lc and winding 22 (i.e., modular winding WM) can also be formed in the vias Via_D of each circuit board CB1, CB2, thereby generating contact pads on the surface of each circuit board CB1, CB2. The modular inductor winding Lc can be electrically connected to the primary side circuit 1A of each circuit board CB1, CB2 via the vias Via_D, and the modular winding 22 can be electrically connected to the primary side circuit 1A or the secondary side circuit 3A of each circuit board CB1, CB2 via the vias Via_D of each circuit board CB1, CB2. In the physical structure of the two circuit boards CB1, CB2, please refer to Figure 14EWhen the power components 400 and traces T (i.e., modular windings WM) on the circuit boards CB1 and CB2 are embedded in the circuit boards CB1 and CB2 using embedding technology, the power components 400 and modular windings WM on each circuit board CB1 and CB2 can be electrically connected via electrical traces Tc_1 and Tc_2, thereby shortening the distance between the power components 400 and the modular windings WM.

[0267] For reference Figures 14A and 14B 、 Figure 16A 、 Figure 16B In the component configuration technology of the physical structure of two circuit boards CB1 and CB2 and the secondary side circuit 3A, the first switch SR1, the second switch SR2, and the output capacitor Co of the circuit board CB1 can be set at one end of the circuit board CB1, and the output capacitor Co is configured between the first switch SR1 and the second switch SR2. The first switch SR1, the second switch SR2, and the output capacitor Co of the circuit board CB2 can also be set at one end of the circuit board CB2, and the output capacitor Co is configured between the first switch SR1 and the second switch SR2. Through the above configuration, the circuit boards CB1 and CB2 can make the current path Li of the secondary side traces Ts-1 and Ts-2 into an arc shape, thereby providing the shortest current path Li and reducing path loss. In one embodiment, Figure 16A 、 Figure 16B Matching Figures 8A to 14B The detailed circuit structure can be consulted repeatedly Figures 8A to 14B 、 Figure 16A 、 Figure 16B .

[0268] For the physical structure of the two circuit boards CB1 and CB2, refer to Figure 15A 、 Figure 15B The two circuit boards CB1 and CB2 respectively include a first switch SR1, a second switch SR2 and an output capacitor Co, and the first switch SR1, the second switch SR2 and the output capacitor Co of the two circuit boards CB1 and CB2 are arranged in the same manner. Figure 15A Specifically, the first switch SR1 and the second switch SR2 of the two circuit boards CB1 and CB2 are disposed on the same side of the first circuit board through-hole CB1_H and the second circuit board through-hole CB2_H, respectively, and the output capacitor Co is disposed between the first switch SR1 and the second switch SR2. In one embodiment, the first switch SR1 and the second switch SR2 are preferably positioned in a mirrored manner with the output capacitor Co as the center, and the components on the two circuit boards CB1 and CB2 are preferably arranged in a mirrored manner.

[0269] For reference Figure 15BIn panel (a), in a physical structure with two circuit boards CB1 and CB2, the first switch SR1, the second switch SR2, and the output capacitor Co of the first circuit board CB1 are arranged on the same surface of the first circuit board CB1, and the first secondary-side trace Ts1 and the second secondary-side trace Ts2 are respectively arranged on at least two layers of the circuit board CB (illustrated by the first sub-layer LA1 and the second sub-layer LA2 of the first circuit board CB1). When the first switch SR1 of the first circuit board CB1 is turned on, current I1 flows from the first switch SR1 on the first sub-layer LA1 around the first circuit board through-hole CB1_H (which may include the first through-hole H1 or the first through-hole H1 and the second through-hole H2) to the output capacitor Co, forming a current path Li_1. When the second switch SR2 of the first circuit board CB1 is turned on, current I2 flows from the second switch SR2 on the second sub-layer LA2 around the first circuit board through-hole CB1_H to the output capacitor Co, forming a current path Li_2. The components of the second circuit board CB2 are the same as those of the first circuit board CB1, and the current paths Li_1 and Li_2 are also the same as those of the first circuit board CB1. Since the directions of the current paths Li_1 and Li_2 are opposite, the magnetic flux can be canceled, thereby improving the overall efficiency of the circuit.

[0270] For reference Figure 15BIn panel (b), in a physical structure comprising two circuit boards CB1 and CB2, the resonant converter 100 includes two sets of secondary-side circuits 3A and two sets of secondary-side traces Ts. The two sets of secondary-side traces Ts include a first secondary-side trace Ts1 and a second secondary-side trace Ts2, respectively. The two sets of secondary-side circuits 3A are disposed on the first circuit board CB1 and the second circuit board CB2, respectively, and each set of secondary-side circuits 3A includes two first switches SR1, two second switches SR2, and two or more output capacitors Co. Within the first circuit board CB1, the two first switches SR1, the two second switches SR2, and at least one output capacitor Co are disposed on two surfaces of the first circuit board CB1, respectively. The first secondary-side trace Ts1 and the second secondary-side trace Ts2 are disposed on at least any four layers of the circuit board CB (illustrated by the first secondary-side trace Ts1 being disposed on sub-layers LA1 and LA2 of the first circuit board CB1, and the second secondary-side trace Ts2 being disposed on sub-layers LA7 and LA8). When the two first switches SR1 on the first circuit board CB1 are turned on, current I1 flows from the first switches SR1 on sub-layers LA1 and LA8, respectively, around the first circuit board through-hole CB1_H (which may include the first through-hole H1 or the first through-hole H1 and the second through-hole H2), to the output capacitor Co, forming a current path Li_1. When the two second switches SR2 on the first circuit board CB1 are turned on, current I2 flows from the second switches SR2 on sub-layers LA2 and LA7, respectively, around the first circuit board through-hole CB1_H, to the output capacitor Co, forming a current path Li_2. The component configuration of the second circuit board CB2 is identical to that of the first circuit board CB1, and the current paths Li_1 and Li_2 are also identical to those of the first circuit board CB1. Because the directions of current paths Li_1 and Li_2 are opposite, they also achieve magnetic flux cancellation, improving overall circuit efficiency.

[0271] For reference Figure 15BIn panel (c), in a physical structure with two circuit boards CB1 and CB2, the resonant converter 100 includes two sets of secondary-side circuits 3A and two sets of secondary-side traces Ts. The two sets of secondary-side traces Ts include a first secondary-side trace Ts1 and a second secondary-side trace Ts2, respectively. The two sets of secondary-side circuits 3A are disposed on the first circuit board CB1 and the second circuit board CB2, respectively, and each set of secondary-side circuits 3A includes a first switch SR1, a second switch SR2, a third switch SR3, a fourth switch SR4, and two or more output capacitors Co. On the first circuit board CB1, the first switch SR1, the second switch SR2, and at least one output capacitor Co are disposed on one surface of the first circuit board CB1, while the third switch SR3, the fourth switch SR4, and at least another output capacitor Co are disposed on the other surface of the first circuit board CB1. The secondary-side traces Ts are disposed on at least two layers of the first circuit board CB1 (illustrated by sub-layers LA1 and LA8 of the first circuit board CB1). When the first switch SR1 and the second switch SR2 of the first circuit board CB1 are turned on, current I1 flows from the first and second switches SR1 and SR2 on the sub-layer LA1, around the first circuit board through-hole CB1_H (which may include the first through-hole H1 or the first and second through-holes H1 and H2), to the output capacitor Co, forming current path Li_1. When the third and fourth switches SR3 and SR4 of the first circuit board CB1 are turned on, current I2, running along the same trace (i.e., the secondary-side trace Ts) but in opposite directions, flows from the third and fourth switches SR3 and SR4 on the second sub-layer LA2, around the first circuit board through-hole CB1_H, to the output capacitor Co, forming current path Li_2. The component configuration of the second circuit board CB2 is identical to that of the first circuit board CB1, and the current paths Li_1 and Li_2 are also identical to those of the first circuit board CB1. Because the directions of current paths Li_1 and Li_2 are opposite, they also achieve magnetic flux cancellation, improving overall circuit efficiency.

[0272] 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, disposed on the circuit board; 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 first through-hole passing through the circuit board; An iron core, comprising a first iron core column passing through the first through hole; A plurality of vias for electrically connecting a first sub-layer board and a second sub-layer board of the circuit board; A plurality of traces are formed around the first through-hole and serve as a winding of the flat-plate transformer; wherein the plurality of traces extend alternately through the plurality of injection holes on the first sub-layer board and the second sub-layer board, and the traces on the same layer are arranged in parallel.

2. The resonant converter of claim 1 , wherein the planar transformer further comprises: a second through hole passing through the circuit board; The iron core further includes a second iron core column passing through the first through-hole, and a plurality of the wirings are formed around the first through-hole and the second through-hole.

3. The resonant converter of claim 1 , wherein the plurality of traces are a plurality of secondary-side traces serving as a secondary-side winding electrically connected to the secondary-side circuit, and the planar transformer further comprises: A primary-side trace is formed on a third sub-layer board of the circuit board and serves as a primary-side winding electrically connected to the primary-side circuit.

4. The resonant converter of claim 3 , wherein the planar transformer further comprises: A first via and a second via are formed on a first side of the first through-hole and a second side opposite to the first side, respectively. The first via is used to electrically connect the first sub-layer board and a fourth sub-layer board of the circuit board, and the second via is used to electrically connect the second sub-layer board and a fifth sub-layer board. A first switch, a second switch, and an output capacitor of the secondary-side circuit are disposed on the second side. and a third via and a fourth via, formed on the first side and opposite to the second side, respectively, the third via being used to electrically connect the first sub-layer board and the fourth sub-layer board, and the fourth via being used to electrically connect the second sub-layer board and the fifth sub-layer board; The plurality of secondary side traces include: a plurality of first secondary-side traces electrically connected to the first switch; and a plurality of second secondary-side traces electrically connecting the plurality of first secondary-side traces and the second switch; The plurality of first secondary-side traces extend from the first sub-layer in a first direction surrounding the first through-hole to the first via, extend through the first via to the fourth sub-layer, and continue in the first direction to the second side to be electrically connected to the output capacitor through the second via. The plurality of first secondary-side traces extend from the second sub-layer plate in a circumferential direction to the first via, extend through the first via to the fifth sub-layer plate, and continue along the first direction to the second side to be electrically connected to the output capacitor through the second via. wherein the plurality of second secondary-side traces extend from the first sub-layer in a second direction surrounding the first through-hole to the third via, extend through the third via to the fourth sub-layer, and continue in the second direction to the second side to be electrically connected to the output capacitor through the fourth via; and The plurality of second-secondary-side traces extend from the second sub-layer plate in a circumferential direction to the third via, extend through the third via to the fifth sub-layer plate, and continue in the second direction to the second side to be electrically connected to the output capacitor through the fourth via. The first direction and the second direction are in opposite circumferential directions along the first through hole.

5. The resonant converter of claim 1 , wherein the plurality of traces are a plurality of primary-side traces serving as a primary-side winding electrically connected to the primary-side circuit, and the planar transformer further comprises: A secondary-side trace is formed on the circuit board and serves as a secondary-side winding electrically connected to the secondary-side circuit.

6. The resonant converter of claim 1 , further comprising: an inductor through-hole penetrating the circuit board; An inductor core includes two covers, each of the two covers includes a main body, and one of the two covers includes two side portions; and an inductor trace electrically connected to the plurality of traces and surrounding the inductor through-hole; The two side portions protrude from the periphery of the body, and one of the two side portions passes through the inductor through-hole. 7 . The resonant converter as claimed in claim 1 , wherein the plurality of traces are formed in a winding area of ​​the circuit board, and the plurality of vias are formed around a periphery of the winding area and a periphery of the first through-hole.

8. The resonant converter of claim 1 , wherein the core further comprises: Two covers, one of which forms the first core column, and each of which includes a main body and a plurality of side portions; The side portions of the two covers are correspondingly protruded from the periphery of the main body, and an air gap is formed on one of the outer sides of the circuit board. 9 . The resonant converter as claimed in claim 1 , wherein traces on different layers form an acute angle with the via as the center, and the acute angle is between 25 degrees and 35 degrees.

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, wherein one end of the output capacitor is electrically connected to one end of the first switch and one end of 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 other end of the output capacitor, and the flat-plate transformer includes: a first through-hole passing through the circuit board; An iron core, comprising a first iron core column passing through the first through hole; A first via and a second via are formed on a first side of the first through-hole and a second side opposite to the first side, respectively, for electrically connecting a first sub-layer board and a second sub-layer board of the circuit board; wherein the first switch, the second switch and the output capacitor are disposed on the second side; and A third filling hole and a fourth filling hole are formed on the first side and the second side respectively for electrically connecting the first sub-layer board and the second sub-layer board; 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 secondary-side trace extends from the first sub-layer in a first direction surrounding the first through-hole to the first via, extends through the first via to the second sub-layer, and continues in the first direction to the second side to be electrically connected to the output capacitor through the second via. The second secondary-side trace extends from the first sub-layer in a second direction surrounding the first through-hole to the third via, extends through the third via to the second sub-layer, and continues in the second direction to the second side to be electrically connected to the output capacitor through the fourth via. The first direction and the second direction are in opposite circumferential directions along the first through hole.

11. The resonant converter of claim 10 , wherein the planar transformer further comprises: a second through-hole passing through the circuit board, and the iron core further comprises a second iron core column passing through the second through-hole; The first and second vias are respectively formed on a third side of the second through-hole and a fourth side opposite to the third side for electrically connecting the first sub-layer board and the second sub-layer board. The third and fourth vias are respectively formed on the third side and the fourth side for electrically connecting the first sub-layer board and the second sub-layer board. The first and second switches are disposed on the fourth side. The first secondary-side trace extends from the first sub-layer in the second direction surrounding the second through-hole to the first via, extends through the first via to the second sub-layer, and continues in the second direction to the fourth side to be electrically connected to the output capacitor through the second via. The second secondary-side trace extends from the first sub-layer plate in the first direction surrounding the second through-hole to the third via, extends to the second sub-layer plate through the third via, and continues in the first direction to the fourth side to be electrically connected to the output capacitor through the fourth via. 12 . The resonant converter as claimed in claim 11 , wherein the first secondary-side traces in the first direction and the second direction are integrally formed, or the second secondary-side traces in the first direction and the second direction are integrally formed.

13. The resonant converter of claim 10, wherein the planar transformer further comprises: A primary-side trace is formed on a third sub-layer board of the circuit board and serves as a primary-side winding electrically connected to the primary-side circuit.

14. The resonant converter of claim 10, further comprising: an inductor through-hole penetrating the circuit board; An inductor core includes two covers, each of the two covers includes a main body, and one of the two covers includes two side portions; and an inductor trace electrically connected to the primary-side trace and surrounding the inductor through-hole; The two side portions protrude from the periphery of the body, and one of the two side portions passes through the inductor through-hole.

15. The resonant converter of claim 10, wherein the core further comprises: Two covers, one of which forms the first core column, and each of which includes a main body and a plurality of side portions; The side portions of the two covers are correspondingly protruded from the periphery of the main body, and an air gap is formed on one of the outer sides of the circuit board.

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