Flyback topology multipath constant voltage power supply circuit with multiple transformers coupled in series

Abstract

The utility model provides a flyback topology multipath constant voltage power supply circuit with a plurality of transformers coupled in series, which comprises a flyback topology circuit structure and at least one topology closed-loop circuit structure cascaded with the flyback topology circuit structure through a secondary transformer, the flyback topology circuit structure comprises a primary side closed-loop circuit structure located on the primary side of the main transformer and a secondary side closed-loop circuit structure located on the secondary side of the main transformer, and a first coupling winding on the secondary side of the main transformer is magnetically coupled with a second coupling winding on the primary side of the secondary transformer. And the dotted terminals of the first coupling winding and the second coupling winding are arranged on the same side, so that the defects of traditional multi-group transformer and multi-closed-loop system control are overcome, and a solution with low cost and high performance is provided.

Description

Technical Field

[0001] The utility model relates to a flyback topology multi-channel constant voltage power supply circuit, in particular to a flyback topology multi-channel constant voltage power supply circuit with a plurality of transformers coupled in series. Background Art

[0002] The flyback topology multi-channel constant voltage circuit is usually used to provide a constant voltage output to multiple loads. There is usually a flyback topology circuit responsible for providing the main voltage output, and there are multiple additional flyback topology circuits responsible for providing other voltage outputs. Each additional flyback topology circuit usually has its own feedback loop to keep its output voltage stable. Because the flyback topology multi-channel constant voltage circuit has the characteristics of efficient energy conversion, stable output voltage, and multiple voltage output terminals, it is usually suitable for applications that require multiple voltage outputs, such as various analog and digital circuits in electronic equipment.

[0003] At present, the common flyback topology multi-channel constant voltage circuit is realized by using a transformer with multiple windings or multiple closed-loop space systems. The multi-winding transformer solution has multiple windings, each of which can have different turns and connection methods to achieve different voltage, current and power conversion solutions. However, this method has the following problems: 1. The transformer skeleton is not hanging enough; 2. After there are more windings, the winding far from the main winding in the transformer space is overloaded, and the winding close to the main winding is lightly loaded. The main MOS voltage spike caused by leakage inductance becomes larger, affecting the reliability of the product; Among them, the solution of multiple closed-loop control system is as follows Figure 1 As shown, Figure 1 (A) corresponds to the way two transformers are cascaded through two closed-loop systems. Figure 1 (B) in the figure corresponds to the method in which two transformers output separately through two closed-loop systems. This method has the following problems: 1. Multiple closed-loop systems need to be debugged separately, and the closed-loop systems may suddenly affect each other, making debugging difficult for relevant personnel; 2. Each closed-loop system requires an independent master control IC, which increases the overall cost and the size of the flyback topology multi-channel constant voltage circuit.

[0004] In summary, there are many problems with the flyback topology multi-channel constant voltage circuits currently on the market, and there is an urgent need for a flyback topology multi-channel constant voltage circuit that can overcome the defects of multiple sets of transformers and multiple closed-loop system control. Utility Model Content

[0005] The purpose of the utility model is to provide a flyback topology multi-channel constant voltage power supply circuit with multiple transformers coupled in series, which overcomes the defects of traditional multiple sets of transformers and multiple closed-loop system control and provides a low-cost and high-performance solution.

[0006] To achieve the above objectives, the present technical solution provides a flyback topology multi-channel constant voltage power supply circuit in which multiple transformers are coupled in series, including: a flyback topology circuit structure and at least one topology closed-loop circuit structure cascaded to the flyback topology circuit structure through a secondary transformer, wherein the flyback topology circuit structure includes a primary side closed-loop circuit structure located on the primary side of a main transformer and a secondary side closed-loop circuit structure located on the secondary side of the main transformer, a first coupling winding on the secondary side of the main transformer is magnetically coupled to a second coupling winding on the primary side of the secondary transformer, and the same-name ends of the first coupling winding and the second coupling winding are arranged on the same side.

[0007] Compared with the prior art, this technical solution has the following characteristics and beneficial effects:

[0008] 1. The flyback topology multi-channel constant voltage circuit provided by this solution adopts the method of series coupling of transformer windings. Compared with the traditional multi-winding transformer solution, it solves the problem of many transformer skeleton pins and excessive voltage spike stress of the main MOS tube under different winding loads.

[0009] 2. The transformer windings of the flyback topology multi-channel constant voltage circuit provided by this solution are coupled by magnetic coupling, and the output voltage of each channel can be set using only the main IC. Compared with the traditional multi-closed-loop system, it solves the problem of mutual influence between multiple closed-loop systems in cascade and the need for separate debugging. At the same time, the method of not requiring multiple ICs also greatly reduces the cost and volume of the flyback topology multi-channel constant voltage circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a circuit structure diagram of a multi-channel constant voltage circuit based on a traditional flyback topology.

[0011] Figure 2 It is a schematic diagram of a flyback multi-channel constant voltage circuit in which two transformer windings are coupled in series in one embodiment of the utility model.

[0012] Figure 3 It is a schematic diagram of a flyback multi-channel constant voltage circuit with three transformer windings coupled in series according to another embodiment of the utility model. DETAILED DESCRIPTION

[0013] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the utility model.

[0014] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0015] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0016] The present solution provides a flyback topology multi-channel constant voltage power supply circuit in which multiple transformers are coupled in series, comprising: a flyback topology circuit structure and at least one topology closed-loop circuit structure cascaded to the flyback topology circuit structure through a secondary transformer, wherein the flyback topology circuit structure comprises a primary side closed-loop circuit structure located on the primary side of a main transformer and a secondary side closed-loop circuit structure located on the secondary side of the main transformer, a first coupling winding on the secondary side of the main transformer is magnetically coupled to a second coupling winding on the primary side of the secondary transformer, and the same-name ends of the first coupling winding and the second coupling winding are arranged on the same side.

[0017] The flyback topology multi-channel constant voltage power supply circuit with multiple transformers coupled in series can achieve the effect of controlling the output of each channel to a predetermined value with one integrated circuit through magnetic coupling between two adjacent transformers. The topological closed-loop circuit structure is not affected by the mutual cascade relationship, thereby reducing the cost and structural volume of the flyback topology multi-channel constant voltage circuit.

[0018] In some embodiments, when a flyback topology multi-channel constant voltage power supply circuit in which multiple transformers are coupled in series has at least two cascaded topological closed-loop circuit structures, the topological closed-loop circuit structure located at the front of the cascade among the two adjacent cascaded topological closed-loop circuit structures is the first topological closed-loop circuit structure, and the topological closed-loop circuit structure located at the back of the cascade is the second topological closed-loop circuit structure, and the third coupling winding on the secondary side of the secondary transformer of the first topological closed-loop circuit structure is magnetically coupled with the fourth coupling winding on the primary side of the secondary transformer of the second topological closed-loop circuit structure, and the same-name ends of the third coupling winding and the fourth coupling winding are arranged on the same side.

[0019] The secondary side closed-loop circuit structure and the topological closed-loop circuit structure provided by the present solution both include at least one closed-loop feedback circuit.

[0020] like Figure 2 As shown, Figure 2 This is the case where the flyback topology multi-channel constant voltage power supply circuit with multiple transformers coupled in series has only one topology closed-loop circuit structure, at which time the main transformer corresponding to the flyback topology multi-channel constant voltage circuit is magnetically coupled with the secondary transformer of the topology closed-loop circuit structure, and the first coupling winding of the main transformer on the secondary side and the second coupling winding of the secondary transformer on the primary side are on the same side. The advantage of this arrangement is that when the MOS tube on the primary side of the flyback topology circuit structure is turned on, the diodes in the corresponding topology closed-loop circuit structure are all cut off.

[0021] The primary side closed-loop circuit structure includes a MOS tube Q2, a storage capacitor C1, a diode D6, a resistor R1, and a primary winding T1A located on the primary side of the main transformer T1, wherein the gate of the MOS tube Q2 is connected to the input signal, the source is grounded, the drain is respectively connected to the diode D6 and the primary winding T1A, the other end of the diode D6 is respectively connected to the storage capacitor C1 and the resistor R1, and one end of the primary winding T1A, the resistor R1, and the storage capacitor C1 are connected to the bus BUS.

[0022] Each secondary side closed loop circuit structure is a closed loop circuit composed of a rectifier diode, a secondary winding and a polar capacitor, wherein the negative electrode of the polar capacitor is grounded. In the embodiment of the present scheme, two secondary side closed loop circuit structures are provided on the secondary side of the main transformer in the flyback topology circuit structure.

[0023] In a specific embodiment of the present solution, the secondary side closed circuit structure of the flyback topology multi-channel constant voltage power supply circuit with multiple transformers coupled in series includes two closed-loop feedback circuits, and the topology closed-loop circuit structure includes three closed-loop feedback circuits.

[0024] like Figure 3 As shown, Figure 3 This is a situation where the flyback topology multi-channel constant voltage power supply circuit with multiple transformers coupled in series has two topology closed-loop circuit structures. At this time, the main transformer corresponding to the flyback topology multi-channel constant voltage circuit is magnetically coupled with the secondary transformer of the topology closed-loop circuit structure, and the first coupling winding of the main transformer on the secondary side and the same-name end of the second coupling winding of the secondary transformer on the primary side are located on the same side, and the third coupling winding on the secondary side of the secondary transformer of the first topology closed-loop circuit structure is magnetically coupled with the fourth coupling winding on the primary side of the secondary transformer of the second topology closed-loop circuit structure, and the same-name ends of the third coupling winding and the fourth coupling winding are arranged on the same side. The advantage of such an arrangement is that when the MOS tube on the primary side of the flyback topology circuit structure is turned on, the diodes in the corresponding topology closed-loop circuit structure are all cut off.

[0025] Specifically, at this time, there are two closed-loop feedback circuits in the first topology closed-loop circuit structure, and three closed-loop feedback circuits in the second topology closed-loop circuit structure. The third coupling winding on the secondary side of the secondary transformer of the first topology closed-loop circuit structure is magnetically coupled with the fourth coupling winding on the primary side of the secondary transformer of the second topology closed-loop circuit structure.

[0026] The present utility model is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present utility model. However, no matter what changes are made in the shape or structure, all those having the same or similar technical solutions as the present application fall within the protection scope of the present utility model.

Claims

1. A flyback topology multi-channel constant voltage power supply circuit with multiple transformers coupled in series, characterized in that: include: A flyback topology circuit structure and at least one topology closed-loop circuit structure cascaded to the flyback topology circuit structure through a secondary transformer, wherein the flyback topology circuit structure includes a primary-side closed-loop circuit structure located on the primary side of a main transformer and a secondary-side closed-loop circuit structure located on the secondary side of the main transformer, a first coupling winding on the secondary side of the main transformer is magnetically coupled to a second coupling winding on the primary side of the secondary transformer, and the same-named ends of the first coupling winding and the second coupling winding are arranged on the same side.

2. The flyback topology multi-channel constant voltage power supply circuit with multiple transformers coupled in series according to claim 1, characterized in that: When the flyback topology multi-channel constant voltage circuit has at least two cascaded topological closed-loop circuit structures, the topological closed-loop circuit structure located at the front of the cascade among the two adjacent cascaded topological closed-loop circuit structures is the first topological closed-loop circuit structure, and the topological closed-loop circuit structure located at the back of the cascade is the second topological closed-loop circuit structure, the third coupling winding on the secondary side of the secondary transformer of the first topological closed-loop circuit structure is magnetically coupled with the fourth coupling winding on the primary side of the secondary transformer of the second topological closed-loop circuit structure, and the same-name ends of the third coupling winding and the fourth coupling winding are arranged on the same side.

3. The flyback topology multi-channel constant voltage power supply circuit with multiple transformers coupled in series according to claim 1, characterized in that: Both the secondary side closed-loop circuit structure and the topological closed-loop circuit structure include at least one closed-loop feedback circuit.

4. The flyback topology multi-channel constant voltage power supply circuit with multiple transformers coupled in series according to claim 1, characterized in that: Each secondary-side closed-loop circuit structure is a closed-loop circuit composed of a rectifier diode, a secondary winding, and a polarized capacitor, wherein the negative electrode of the polarized capacitor is grounded.

5. The flyback topology multi-channel constant voltage power supply circuit with multiple transformers coupled in series according to claim 2, characterized in that: There are two closed-loop feedback circuits in the first topology closed-loop circuit structure, and three closed-loop feedback circuits in the second topology closed-loop circuit structure. The third coupling winding on the secondary side of the secondary transformer of the first topology closed-loop circuit structure is magnetically coupled with the fourth coupling winding on the primary side of the secondary transformer of the second topology closed-loop circuit structure.

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