Flat transformer circuit and flat transformer
By dividing the primary winding of the planar transformer into two parts and connecting them using MOSFETs, the shielding and auxiliary windings are eliminated, thus solving the problem of complex PCB winding board structure and achieving the effects of simplified structure and reduced cost.
Patent Information
- Application Number
- CN202423071482.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2034-12-12
AI Technical Summary
Existing planar transformers have complex PCB winding board structures, numerous layers, and complex wiring structures, making it difficult to meet the requirements of small size and high power density.
The primary winding is divided into a first winding and a second winding, and their connection is realized by using the MOSFET of the PWM controller. The shielding winding and auxiliary winding are eliminated, simplifying the PCB board structure.
Reduce common-mode interference, improve EMI characteristics, simplify PCB board structure, reduce costs, and achieve efficient power conversion.
Smart Images
Figure CN223566425U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the field of flat transformer. BACKGROUND
[0002] The power adapter is the equipment that converts alternating current into low voltage direct current and charges the battery in the electronic product to provide electric energy. With the development of technology, small size, high power density and high integration become the pursuit target and development direction of the power adapter, so a flat transformer is arranged in the power adapter as the core electric energy conversion component, the flat transformer has the advantages of small size and high current density, can fully realize efficient electric energy power conversion, and is widely used.
[0003] The electric energy conversion of the flat transformer is realized through the core PCB winding plate, the traditional PCB winding plate is provided with a coil winding on each layer of PCB plate, and electric conversion is realized by the coil windings. The existing PCB winding plate includes a plurality of layer plates arranged with a primary winding, a secondary winding, a shielding layer winding and an auxiliary winding, and the number of layer plates is large and the wiring structure is complex. The applicant believes that the PCB winding plate can be further optimized. SUMMARY
[0004] In order to overcome the shortcomings of the prior art, the utility model provides a kind of flat transformer circuit and the flat transformer using the above-mentioned circuit.
[0005] The technical scheme adopted by the utility model to solve its technical problems is:
[0006] A kind of flat transformer circuit, including input side circuit, primary winding, secondary winding and output side circuit, the input side circuit includes PWM controller with MOS tube, the primary winding is divided into first winding and second winding, and first winding and second winding are connected with the D pole and S pole of MOS tube respectively to realize communication combination.
[0007] The input side circuit further includes EMI module, input rectification filter module and conversion power supply module;The first end of the first winding is connected to the EMI module through the input rectification filter module, and the second end of the first winding is connected to the D pole of the MOS tube;The first end of the second winding is connected to the S pole of the MOS tube, and the second end is connected to the common terminal;The input end of the conversion power supply module is connected to the input rectification filter module, and the output end is connected to the PWM controller, and the voltage of the first winding is rectified by the input rectification filter module and converted into electric energy by the conversion power supply module to supply the PWM controller.
[0008] The output side circuit includes output rectification filter module, and the first and second ends of the secondary winding are connected to the output rectification filter module.
[0009] A planar transformer adopting the planar transformer circuit comprises a magnetic core, a PCB winding plate and a circuit board, the input side circuit and the output side circuit are arranged on the circuit board, the primary winding and the secondary winding are arranged on the PCB winding plate, the PCB winding plate is composed of a top layer PCB board, a second layer PCB board, a third layer PCB board and a bottom layer PCB board, the first winding of the primary winding is arranged on the top layer PCB board, the second winding of the primary winding is arranged on the bottom layer PCB board, the secondary winding is arranged on the second layer PCB board and the third layer PCB board and is connected in series through the electric copper needle, a plurality of groups of gold fingers are arranged on both sides of the PCB winding plate to form a primary electric terminal and a secondary electric terminal, and the primary electric terminal and the secondary electric terminal are connected with the input side circuit and the output side circuit on the circuit board respectively, wherein the primary electric terminal has a D port and an S port connected with a D pole and an S pole of a MOS tube in the PWM controller.
[0010] The utility model discloses an improvement circuit, divides the primary winding into first winding and second winding, and utilizes the MOS tube on the PWM controller to realize the connection combination of first winding and second winding and forms the primary winding, after the primary winding is divided into first winding and second winding, the voltage of first winding and second winding respectively is reduced by apportioning, on one hand, after first winding or second winding is connected with the common terminal, can reduce common mode interference, improves EMI characteristic, reaches the purpose of optimizing shielding winding structure or even cancelling shielding winding. BRIEF DESCRIPTION OF DRAWINGS
[0011] The utility model is further explained below in connection with the drawings and examples.
[0012] Figure 1 It is the circuit schematic diagram of the utility model planar transformer circuit;
[0013] Figure 2 It is the wiring schematic diagram of the winding in the utility model planar transformer circuit;
[0014] Figure 3 It is the structure schematic diagram of the top layer PCB board of the utility model;
[0015] Figure 4 It is the structure schematic diagram of the second layer PCB board of the utility model;
[0016] Figure 5 It is the structure schematic diagram of the third layer PCB board of the utility model;
[0017] Figure 6 It is the structure schematic diagram of the bottom layer PCB board of the utility model. Detailed Implementation
[0018] Reference Figure 1 , Figure 2 A planar transformer circuit includes an input side circuit, a primary winding 4, a secondary winding 6, and an output side circuit.
[0019] The input-side circuit includes a PWM controller 3 with a MOSFET. The primary winding 4 is divided into a first winding 41 and a second winding 42. The first winding 41 and the second winding 42 are connected to the drain (D) and source (S) terminals of the MOSFET, respectively, to form the primary winding 4. After the primary winding 4 is divided into the first winding 41 and the second winding 42, the voltages of the first winding 41 and the second winding 42 are reduced by sharing, i.e., the voltage of the first winding 41 + the voltage of the second winding 42 = the operating voltage of the primary winding 4. In this way, on the one hand, by connecting the first winding 41 or the second winding 42 to a common terminal, common-mode interference can be reduced, EMI characteristics can be improved, and the shielding winding structure can be optimized or even eliminated. On the other hand, the first winding 41 or the second winding 42 can be used as an auxiliary winding, thereby eliminating the auxiliary winding and reducing the number of layers for arranging the auxiliary winding. Ultimately, this simplifies the PCB structure and optimizes the PCB cost.
[0020] In this embodiment, the auxiliary power supply scheme using the first winding 41 is specifically further comprising an EMI module 1, an input rectification and filtering module 2, and a conversion power supply module 5. The EMI module 1 is connected to the first end of the first winding 41 via the input rectification and filtering module 2, and the second end of the first winding 41 is connected to the drain (D) terminal of the MOSFET. The first end of the second winding 42 is connected to the source (S) terminal of the MOSFET, and the second end is connected to the common terminal. The input end of the conversion power supply module 5 is connected to the input rectification and filtering module 2, and the output end is connected to the PWM controller 3. The voltage of the first winding 41 is re-rectified by the input rectification and filtering module 2 and then converted into electrical energy by the conversion power supply module 5 to supply power to the PWM controller 3.
[0021] In this embodiment, the output side circuit includes an output rectifier and filter module 7. The first and second ends of the secondary winding 6 are connected to the output rectifier and filter module 7, and a stable current is output using the output rectifier and filter module 7.
[0022] This utility model also provides a planar transformer using the above-mentioned planar transformer circuit, including a magnetic core 8, a PCB winding board and a circuit board, with the input circuit and output circuit arranged on the circuit board, and the primary winding 4 and the secondary winding 6 arranged on the PCB winding board.
[0023] like Figures 3 to 6As shown, the PCB winding plate is composed of a top layer PCB plate 91, a second layer PCB plate 92, a third layer PCB plate 93 and a bottom layer PCB plate 94, the first winding 41 of the primary winding 4 is arranged on the top layer PCB plate 91, and the second winding 42 of the primary winding 4 is arranged on the bottom layer PCB plate 94. The secondary winding 6 is arranged on the second layer PCB plate 92 and the third layer PCB plate 93 and is connected in series through the copper needle.
[0024] A plurality of gold fingers are arranged on both sides of the PCB winding plate to form a primary power connection end and a secondary power connection end, the primary power connection end and the secondary power connection end are connected with input side circuits and output side circuits on the circuit board respectively, wherein the primary power connection end has four ports corresponding to two ends of the first winding 41 and the second winding 42, and two ports are D ports and S ports connected with D poles and S poles of MOS tubes in the PWM controller 3.
[0025] Finally, the PCB winding plate of the utility model can constitute a 4-layer PCB plate structure because the layer plates arranged with the shielding winding and the auxiliary winding are reduced.
Claims
1. A planar transformer circuit comprising an input side circuit, a primary winding (4), a secondary winding (6) and an output side circuit, characterized in that, The input side circuit includes a PWM controller (3) with MOS tubes, the primary winding (4) is divided into a first winding (41) and a second winding (42), the first winding (41) and the second winding (42) are connected to the D pole and the S pole of the MOS tube respectively to realize a communication combination.
2. The planar transformer circuit of claim 1, wherein: The input side circuit further includes an EMI module (1), an input rectification filtering module (2), and a conversion power supply module (5); the EMI module (1) is connected to the first end of the first winding (41) through the input rectification filtering module (2), the second end of the first winding (41) is connected to the D pole of the MOS tube; the first end of the second winding (42) is connected to the S pole of the MOS tube, and the second end is connected to a common end; the input end of the conversion power supply module (5) is connected to the input rectification filtering module (2), and the output end is connected to the PWM controller (3); the voltage of the first winding (41) is rectified again by the input rectification filtering module (2) and converted into electric energy by the conversion power supply module (5) to supply the PWM controller (3).
3. The planar transformer circuit of claim 1, wherein: The output side circuit includes an output rectification filtering module (7), and the first and second ends of the secondary winding (6) are connected to the output rectification filtering module (7).
4. A planar transformer employing the planar transformer circuit according to any one of claims 1 to 3, comprising a magnetic core (8), a PCB winding plate and a circuit board, characterized in that: The input side circuit and the output side circuit are arranged on a circuit board, the primary winding (4) and the secondary winding (6) are arranged on a PCB winding board, the PCB winding board is composed of a top layer PCB board (91), a second layer PCB board (92), a third layer PCB board (93), and a bottom layer PCB board (94), the first winding (41) of the primary winding (4) is arranged on the top layer PCB board (91), the second winding (42) of the primary winding (4) is arranged on the bottom layer PCB board (94), the secondary winding (6) is arranged on the second layer PCB board (92) and the third layer PCB board (93) and is connected in series through a copper needle, and the PCB winding board is provided with a plurality of groups of gold fingers on both sides to form a primary power connection end and a secondary power connection end, the primary power connection end and the secondary power connection end are connected to the input side circuit and the output side circuit on the circuit board respectively, and the primary power connection end has a D port and an S port connected to the D pole and the S pole of the MOS tube in the PWM controller (3).