CN217933417U

CN217933417U - Transformer and asymmetric half-bridge flyback conversion circuit

Info

Publication number: CN217933417U
Application number: CN202221943271.7U
Authority: CN
Inventors: 焦德智; 王葆华
Original assignee: Qianrun Electronic Technology Suzhou Co ltd
Current assignee: Qianrun Electronic Technology Suzhou Co ltd
Priority date: 2022-07-26
Filing date: 2022-07-26
Publication date: 2022-11-29
Anticipated expiration: 2032-07-26

Abstract

The utility model discloses a transformer and asymmetric half-bridge flyback conversion circuit, including first magnetic core, second magnetic core, primary winding, secondary winding, auxiliary winding, primary winding is by stranded wire wound line cake structure, secondary winding comprises multilayer PCB board, auxiliary winding comprises multilayer PCB board, secondary winding with auxiliary winding is located same multiply wood. The utility model discloses a transformer for asymmetric half-bridge flyback conversion circuit simple structure, equipment are simple and convenient to solved EMC's problem, both offset former limit winding to the EMI noise interference of secondary winding, improved the EMS performance of transformer itself again.

Description

Transformer and asymmetric half-bridge flyback conversion circuit

Technical Field

The utility model relates to a transformer technical field, and especially relate to a transformer that is used for asymmetric half-bridge to turn over converter circuit.

Background

With the development of power supply technology, the application of the asymmetric half-bridge flyback conversion circuit with high frequency and high efficiency in an isolated power supply is more and more extensive. In the design of the asymmetric half-bridge flyback conversion circuit, the design of a transformer is the core of the design. Generally, a transformer for an asymmetric half-bridge flyback conversion circuit has two implementation modes, namely a traditional winding type transformer and a multi-layer board transformer. The traditional winding type transformer adopts a sandwich structure for winding, the primary side of the traditional winding type transformer generally uses stranded wires, and the secondary side of the traditional winding type transformer generally uses three layers of insulated wires. However, the conventional winding type transformer is highly dependent on manual manufacturing, the processing cost is high, and the consistency of winding is poor. Multi-layer board transformers typically use twelve or fourteen boards with the primary or secondary windings placed on different layers to form a sandwich structure. However, the multilayer board transformer has more layers, complex manufacturing process and higher price; meanwhile, in order to solve the problem of EMC, an additional shielding layer is usually added to the multi-layer transformer for EMI noise shielding, which may increase the number of layers of the transformer and the manufacturing cost.

SUMMERY OF THE UTILITY MODEL

To the above problem, the utility model provides a mixed structure's a transformer that is used for asymmetric half-bridge flyback conversion circuit simplifies the structure of transformer through the combination of line cake structure and multilayer plate structure.

In order to achieve the purpose, the utility model adopts the technical proposal that:

a transformer comprises a first magnetic core, a second magnetic core, a primary winding, a secondary winding and an auxiliary winding, wherein the primary winding is in a wire cake structure formed by winding stranded wires, the secondary winding is formed by a plurality of layers of PCBs, the auxiliary winding is formed by a plurality of layers of PCBs, and the secondary winding and the auxiliary winding are located in the same multi-layer board.

The secondary winding is composed of four or six layers of PCB boards, and the auxiliary winding is positioned on one or more layers of PCB boards.

The primary winding is stacked directly above the secondary winding, the first magnetic core is stacked below the multilayer board, and the second magnetic core is stacked above the primary winding.

An asymmetric half-bridge flyback conversion circuit comprises the transformer, a first switch tube, a second switch tube, a first capacitor, a second capacitor, a first diode and a drive circuit, wherein the first switch tube and the second switch tube are connected in series in the same direction, two ends of the series connection are connected in parallel with input voltage, the series midpoint of the first switch tube and the second switch tube is connected with the first end of the first capacitor, the second end of the first capacitor is connected with the different name end of a primary winding of the transformer, the same name end of the primary winding of the transformer is connected with the source electrode of the second switch tube, the same name end of a secondary winding of the transformer is connected with the anode of the first diode, the cathode of the first diode is connected with the first end of the second capacitor, the second end of the second capacitor is connected with the different name end of the secondary winding of the transformer, two ends of the second capacitor are output ends, and the auxiliary winding is connected in parallel with the drive circuit.

The transformer has the advantages that the structure of the transformer is simplified by combining the wire cake structure and the multi-layer plate structure, the manufacturing difficulty of the transformer is reduced, and the volume and the cost are reduced simultaneously; and the problem of EMC is solved, the EMI noise interference of the primary winding to the secondary winding is counteracted, and the EMS performance of the transformer is improved. Furthermore, the utility model discloses a transformer is used for asymmetric half-bridge to turn over the converter circuit backward, has improved asymmetric half-bridge and has turned over the converter circuit's efficiency backward.

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1 is the circuit schematic diagram of the asymmetric half-bridge flyback conversion circuit of the present invention.

Fig. 2 is a schematic structural diagram of an embodiment of the transformer in fig. 1.

Fig. 3 is a schematic view of the transformer of fig. 2 after assembly.

In the drawings, like reference numerals refer to the same drawing elements.

Detailed Description

In order to make the purpose and technical solution of the embodiments of the present invention clearer, the following description will clearly and completely describe the technical solution of the embodiments of the present invention by combining the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only some of the embodiments of the present invention, and not all of them. All other embodiments, which can be obtained by a person skilled in the art without any inventive work based on the described embodiments of the present invention, belong to the protection scope of the present invention.

Fig. 1 is the circuit schematic diagram of the asymmetric half-bridge flyback conversion circuit of the present invention. As shown in fig. 1, the asymmetric half-bridge flyback converter circuit includes a transformer T1, where the transformer T1 includes a primary winding N1, a secondary winding N2, and an auxiliary winding N3. The asymmetric half-bridge flyback conversion circuit further comprises a switch tube Q1 and a switch tube Q2, wherein the switch tube Q1 and the switch tube Q2 are connected in series in the same direction, and two ends of the switch tube Q1 and an input voltage V are connected in series _in And (4) connecting in parallel. The switching tube Q1 and the switching tube Q2 are connected in series at the midpoint thereof to be connected with a first end of a capacitor C1, a second end of the capacitor C1 is connected with a synonym end of the primary winding N1, and a homonym end of the primary winding N1 is connected with a source electrode of the switching tube Q2. The dotted terminal of the secondary winding N2 is connected with the anode of a diode D1, the cathode of the diode D1 is connected with the first end of a capacitor C2, the second end of the capacitor C2 is connected with the dotted terminal of the secondary winding N2, and two ends of the capacitor C2 output voltage V _o . The auxiliary winding N3 is positioned on the primary side and is connected with the V _CC The driving circuits are connected in parallel, and the auxiliary winding N3 is used for providing a voltage V _CC For use with devices on the primary side.

Fig. 2 is a schematic structural diagram of an embodiment of the transformer in fig. 1. As shown in fig. 2, in fig. 1, the transformer T1 adopts a hybrid structure, the primary winding N1 is formed by winding multiple strands into a wire cake structure, the secondary winding N2 adopts a multilayer board structure, the auxiliary winding N3 also adopts a multilayer board structure, the secondary winding N2 and the auxiliary winding N3 are located in the same multilayer board T13, and T11 and T12 are magnetic cores of the transformer T1. Preferably, the multilayer board T13 is a four-layer board or a six-layer board, the secondary winding N2 is implemented by using four-layer or six-layer PCB boards, and the auxiliary winding N3 is located on one or more of the four-layer or six-layer PCB boards. The auxiliary winding N3 can cancel the EMI noise interference of the primary winding N1 to the secondary winding N2.

When the transformer is assembled, the primary winding N1 is stacked right above the secondary winding N2 in the multilayer board T13, the magnetic core T12 is stacked below the multilayer board T13, and the magnetic core T11 is stacked above the primary winding N1. Fig. 3 is a schematic diagram of the assembled transformer T1.

The utility model discloses a transformer for asymmetric half-bridge flyback conversion circuit simple structure, equipment are simple and convenient to solve EMC's problem, both offset former limit winding to the EMI noise interference of vice limit winding, improved the EMS performance of transformer itself again.

Although the present invention has been described with reference to the above embodiments, it is not intended to limit the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention.

Claims

1. A transformer is characterized by comprising a first magnetic core, a second magnetic core, a primary winding, a secondary winding and an auxiliary winding, wherein the primary winding is in a wire cake structure formed by winding stranded wires, the secondary winding is formed by multiple layers of PCBs, the auxiliary winding is formed by multiple layers of PCBs, and the secondary winding and the auxiliary winding are located in the same multilayer board.

2. The transformer of claim 1, wherein the secondary winding is formed of four or six layers of PCB boards, and the secondary winding is located on one or more of the layers of PCB boards.

3. The transformer of claim 2, wherein the primary winding is stacked directly above the secondary winding, the first magnetic core is stacked below the multilayer board, and the second magnetic core is stacked above the primary winding.

4. An asymmetric half-bridge flyback conversion circuit, comprising a transformer as claimed in any one of claims 1 to 3, further comprising a first switch tube, a second switch tube, a first capacitor, a second capacitor, a first diode, and a driving circuit, wherein the first switch tube and the second switch tube are connected in series in the same direction, the two ends of the series are connected in parallel with an input voltage, the midpoint of the series connection of the first switch tube and the second switch tube is connected to the first end of the first capacitor, the second end of the first capacitor is connected to the different name end of the primary winding of the transformer, the same name end of the primary winding of the transformer is connected to the source of the second switch tube, the same name end of the secondary winding of the transformer is connected to the anode of the first diode, the cathode of the first diode is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the different name end of the secondary winding of the transformer, the two ends of the second capacitor are output ends, and the auxiliary winding is connected in parallel with the driving circuit.