Switching power supply control circuit, control method and switching power supply

Abstract

The present invention provides a switch power supply control circuit, a control method and a switch power supply, wherein the control circuit includes a main control circuit and a first capacitor, wherein the main control circuit controls the switch power supply to work; when the switch power supply works normally, the first capacitor stores energy; when the external power supply of the main control circuit is powered off, the first capacitor supplies power to the main control circuit, and the main control circuit is reset. When the external power supply of the main control circuit is powered off, the first switch tube can be turned off in time.

Description

Technical Field

[0001] The present invention relates to the field of power electronics, and in particular to a switching power supply control circuit, a control method and a switching power supply. Background Art

[0002] In an existing bridge switching power supply or other switching power supply requiring multiple switching tubes, when the control circuit of one of the switching tubes is suddenly powered off, the remaining switching tubes are still working, which may cause functional errors or even damage to the switching power supply. Summary of the invention

[0003] The purpose of the present invention is to provide a switching power supply control circuit, a control method and a switching power supply, which can disconnect all switching tubes in time when the external power supply of the main control circuit is suddenly cut off, so as to solve the problem in the prior art that the switching tubes cannot be turned off in time when the external power supply of the main control circuit is suddenly cut off.

[0004] To achieve the above-mentioned purpose, the present invention provides a switching power supply control circuit, including a main control circuit and a first capacitor, wherein the main control circuit controls the operation of the switching power supply; when the switching power supply works normally, the first capacitor stores energy; when the external power supply of the main control circuit is cut off, the first capacitor supplies power to the main control circuit and the main control circuit is reset.

[0005] Optionally, the control circuit also includes a first control circuit that controls the first switch tube, and the main control circuit is connected to the first control circuit; when the external power supply of the main control circuit is cut off, the main control circuit outputs a reset signal to the first control circuit, and the first control circuit controls the first switch tube to turn off.

[0006] Optionally, the control circuit further includes a bootstrap capacitor, which is connected to the first control circuit. When the external power supply of the main control circuit is powered off, the bootstrap capacitor supplies power to the first control circuit.

[0007] Optionally, the control circuit further includes a second control circuit for controlling a second switch tube, and the main control circuit is connected to the second control circuit.

[0008] The present invention also provides a switching power supply control method. When the switching power supply works normally, the first capacitor stores energy and the main control circuit controls the operation of the switching power supply. When the external power supply of the main control circuit is powered off, the first capacitor supplies power to the main control circuit and the main control circuit is reset.

[0009] Optionally, the first control circuit controls the first switch tube, and the main control circuit is connected to the first control circuit; when the external power supply of the main control circuit is cut off, the main control circuit outputs a reset signal to the first control circuit, and the first control circuit controls the first switch tube to turn off.

[0010] The present invention also provides a switching power supply, comprising any one of the above switching power supply control circuits.

[0011] Compared with the prior art, the present invention has the following advantages: when the switch power supply works normally, the first capacitor stores energy and the main control circuit controls the switch power supply to work; when the external power supply of the main control circuit is powered off, the first capacitor supplies power to the main control circuit and the main control circuit is reset. When the external power supply of the main control circuit is powered off, the present invention can turn off the switch tube in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The principle diagram of the switching power supply control circuit of the present invention; DETAILED DESCRIPTION

[0013] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, but the present invention is not limited to these embodiments. The present invention covers any substitution, modification, equivalent method and scheme made within the spirit and scope of the present invention.

[0014] In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without these detailed descriptions.

[0015] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. It should be noted that the accompanying drawings are all simplified and not in exact proportions, in order to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0016] like Figure 1 As shown, a schematic diagram of the switch power supply control circuit of the present invention is illustrated, including a first control circuit for controlling the first switch tube M1 of the switch power supply, a second control circuit for controlling the second switch tube M2 of the switch power supply, a main control circuit and a first capacitor C00. The main control circuit is connected to the first control circuit and the second control circuit respectively. When the switch power supply works normally, the first capacitor C00 stores energy, and the main control circuit controls the switch power supply to work; when the external power supply of the main control circuit is powered off, the first capacitor C00 supplies power to the main control circuit, the main control circuit is reset, and the main control circuit outputs a reset signal to the first control circuit, and the first control circuit controls the first switch tube to turn off. The control circuit also includes a bootstrap capacitor C1, which is connected to the first control circuit. When the external power supply of the main control circuit is powered off, the bootstrap capacitor supplies power to the first control circuit. The switch power supply is a bridge circuit, a BUCK circuit, a BOOST circuit, a Flybuck circuit, etc.

[0017] Although the embodiments are described and illustrated separately above, some common technologies are involved. It is the opinion of ordinary technicians in this field that the embodiments can be replaced and integrated. If the content is not clearly recorded in one of the embodiments, reference can be made to another recorded embodiment.

[0018] The above-described implementation methods do not constitute a limitation on the protection scope of the technical solution. Any modification, equivalent replacement and improvement made within the spirit and principle of the above-described implementation methods shall be included in the protection scope of the technical solution.

Claims

1. A switching power supply control circuit, characterized in that: It includes a main control circuit and a first capacitor, wherein the main control circuit controls the operation of the switch power supply; when the switch power supply operates normally, the first capacitor stores energy; when the external power supply of the main control circuit is powered off, the first capacitor supplies power to the main control circuit, and the main control circuit is reset; The control circuit also includes a first control circuit for controlling a first switch tube, and the main control circuit is connected to the first control circuit; when the external power supply of the main control circuit is cut off, the main control circuit outputs a reset signal to the first control circuit, and the first control circuit controls the first switch tube to turn off.

2. The switching power supply control circuit according to claim 1, characterized in that: The control circuit further includes a bootstrap capacitor, which is connected to the first control circuit. When the external power supply of the main control circuit is powered off, the bootstrap capacitor supplies power to the first control circuit.

3. The switching power supply control circuit according to claim 2, characterized in that: The control circuit also includes a second control circuit for controlling a second switch tube, and the main control circuit is connected to the second control circuit.

4. A switching power supply control method, characterized in that: When the switching power supply works normally, the first capacitor stores energy and the main control circuit controls the switching power supply to work; when the external power supply of the main control circuit is powered off, the first capacitor supplies power to the main control circuit and the main control circuit is reset; the first control circuit controls the first switch tube, and the main control circuit is connected to the first control circuit; when the external power supply of the main control circuit is powered off, the main control circuit outputs a reset signal to the first control circuit, and the first control circuit controls the first switch tube to turn off.

5. A switching power supply, characterized in that: The invention comprises the switching power supply control circuit as described in claim 1, 2 or 3 above.

Images