Switching power supply with ORing control circuit

Abstract

The present invention provides a switching power supply with an ORing control circuit, which mainly includes a protection circuit connected to the ORing control circuit, including: the source of a MOS tube Q1 is connected to the first output end of a power conversion circuit B1, the drain is connected to Vout+, and the gate is connected to the signal output end of the ORing control circuit; the positive electrode of a diode D1 is connected to the first output end of the power conversion circuit B1, the negative electrode of the diode D1 is connected to the first end of a resistor R3, and the second end of the resistor R3 is connected to the second output end of the power conversion circuit B1; the first end of the resistor R3 is also connected to the base of a transistor Q3, the emitter of the transistor Q3 is connected to Vout+ through a resistor R1, and the collector is connected to Vout- through a resistor R2; the collector of the transistor Q3 is also connected to the gate of a MOS tube Q2, the source of the MOS tube Q2 is connected to the second output end of the power conversion circuit B1, and the drain is connected to the signal input end of the ORing control circuit. By adopting the switching power supply of the present invention, after the power supply is turned off, the energy of the load end can be prevented from being fed back to the power supply end in time.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of switching power supplies, and in particular to a switching power supply with an ORing control circuit. Background Art

[0002] In the rapid development of electronic technology, switching power supplies have become an important part of many devices and have been widely used in all walks of life. Its wide application is due to its many advantages. Compared with linear power supplies, it converts input electrical energy into required electrical energy through high-frequency switching. This method of electrical energy conversion is highly efficient and greatly reduces energy loss. Since the operating frequency of the switching power supply is very high, generally tens of kilohertz to hundreds of kilohertz, the volume of the magnetic devices therein can be greatly reduced, making the switching power supply smaller in size and lighter in weight. In addition, the switching power supply usually has the characteristics of a wide input voltage range, adjustable output voltage, high stability, fast dynamic response, and can be used in parallel, which makes it highly adaptable and flexible in application. The switching power supply can be seen in many power conversion occasions.

[0003] With the diversification of the development of switching power supply technology and the diversification of application scenarios, while the functions of switching power supplies are increasing, the demands on external power-consuming equipment are becoming more and more diversified. Some equipment requires the output voltage to be maintained for a period of time after the switching power supply is shut down, which requires the addition of energy storage capacitors at the output end of the switching power supply; some equipment has high power and requires two or even more switching power supplies to be used in parallel, etc. These application scenarios require the switching power supply energy to be transmitted unidirectionally, because the energy flowing into the switching power supply from the output end may cause serious damage to the switching power supply or the upstream and downstream equipment. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a switching power supply with an ORing control circuit, which can timely prevent the energy at the load end from being fed back to the power supply end after the power supply is turned off.

[0005] In order to solve the above technical problems, the present invention provides a switching power supply with an ORing control circuit, comprising: a power conversion circuit B1, wherein the first input terminal and the second input terminal of the power conversion circuit B1 are connected to Vin+ and Vin-, respectively, and the power conversion circuit B1 also includes a first output terminal and a second output terminal, wherein the second output terminal is connected to Vout-; a MOS transistor Q1, wherein the MOS transistor Q1 is an N-channel MOS transistor, and the source of the MOS transistor Q1 is connected to the first output terminal of the power conversion circuit B1, the drain of the MOS transistor Q1 is connected to Vout+, and the gate of the MOS transistor Q1 is connected to the signal output terminal of the ORing control circuit; a diode D1 and a resistor R3 are connected between the first output terminal and the second output terminal of the power conversion circuit B1, wherein the diode D1 and the resistor R3 are connected between the first output terminal and the second output terminal of the power conversion circuit B1, wherein the diode D1 and the resistor R3 are connected to ... The positive electrode of the diode D1 is connected to the first output end of the power conversion circuit B1, the negative electrode of the diode D1 is connected to the first end of the resistor R3, and the second end of the resistor R3 is connected to the second output end of the power conversion circuit B1; the first end of the resistor R3 is also connected to the base of the transistor Q3, the transistor Q3 is a PNP transistor, the emitter of the transistor Q3 is connected to the Vout+ through the resistor R1, and the collector of the transistor Q3 is connected to the Vout- through the resistor R2; the collector of the transistor Q3 is also connected to the gate of the MOS tube Q2, the MOS tube Q2 is an N-channel MOS tube, the source of the MOS tube Q2 is connected to the second output end of the power conversion circuit B1, and the drain of the MOS tube Q2 is connected to the signal input end of the ORing control circuit.

[0006] Furthermore, it also includes a voltage regulator diode D2, the cathode of the voltage regulator diode D2 is connected to the gate of the MOS tube Q2, and the anode of the voltage regulator diode D2 is connected to Vout-.

[0007] Furthermore, it also includes an error amplifier circuit B3 and a PWM control circuit B2, the input end of the error amplifier circuit B3 is connected to the Vout+, the output end of the error amplifier circuit B3 is connected to the input end of the PWM control circuit B2, and the output end of the PWM control circuit B2 is connected to the feedback input end of the power conversion circuit B1.

[0008] Compared with the prior art, the present invention has the following beneficial effects: after the switching power supply is shut down, the ORing control circuit is accelerated to shut down, and the energy at the load end is prevented from being fed back to the power supply end in time, thereby providing an effective protection measure to prevent energy backflow for the switching power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated into and constitute a part of the present invention. The accompanying drawings illustrate embodiments of the present invention and together with the specification serve to explain the principles of the present invention. In the accompanying drawings: Figure 1 It is a structural diagram of a switching power supply with an ORing control circuit; Figure 2 It is a schematic diagram of the structure of a switching power supply according to an embodiment of the present invention. DETAILED DESCRIPTION

[0010] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present invention. For ordinary technicians in this field, the present invention can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0011] It should be understood that when a component is referred to as being "on another component," "connected to another component," "coupled to another component," or "contacting another component," it may be directly on, connected to, coupled to, or contacting the other component, or there may be intervening components. In contrast, when a component is referred to as being "directly on another component," "directly connected to," "directly coupled to," or "directly contacting" another component, there are no intervening components. Similarly, when a first component is referred to as being "electrically in contact with" or "electrically coupled to" a second component, there is an electrical path between the first component and the second component that allows current to flow. The electrical path may include capacitors, coupled inductors, and / or other components that allow current to flow, even without direct contact between conductive components.

[0012] In order to meet the requirement of unidirectional energy transmission, many switching power supplies add ORing control circuits at the output end. Figure 1 As shown, Figure 1 It is a switching power supply with an ORing control circuit, wherein the MOS tube Q1 is an N-channel MOS tube, and the ORing control circuit B4 and the MOS tube Q1 constitute a switch control unit. When the switching power supply is working, the ORing control circuit B4 controls the MOS tube Q1 to be turned on and output the electric energy normally. When the switching power supply is turned off, the ORing control circuit B4 controls the MOS tube Q1 to be turned off to prevent the energy from being fed back to the switching power supply, thereby realizing the unidirectional transmission of the switching power supply energy from Vin to Vout. However, in some cases, the ORing control circuit may not be turned off in time, resulting in part of the energy being fed back to the switching power supply, which may cause the switching power supply to be damaged.

[0013] refer to Figure 2 As shown, the switching power supply of this embodiment includes electronic components such as MOS transistor Q2, MOS transistor Q3, diode D1, voltage regulator diode D2, and resistors R1-R3.

[0014] In some embodiments, the first input terminal and the second input terminal of the power conversion circuit B1 are connected to Vin+ and Vin-, respectively, and the power conversion circuit B1 also includes a first output terminal and a second output terminal, wherein the second output terminal is connected to Vout-. MOS tube Q1 is an N-channel MOS tube, and the source of MOS tube Q1 is connected to the first output terminal of the power conversion circuit B1, the drain of MOS tube Q1 is connected to Vout+, and the gate of MOS tube Q1 is connected to the signal output terminal of the ORing control circuit. A diode D1 and a resistor R3 are connected between the first output terminal and the second output terminal of the power conversion circuit B1, wherein the positive electrode of the diode D1 is connected to the first output terminal of the power conversion circuit B1, the negative electrode of the diode D1 is connected to the first end of the resistor R3, and the second end of the resistor R3 is connected to the second output terminal of the power conversion circuit B1. The first end of the resistor R3 is also connected to the base of the transistor Q3, which is a PNP transistor, the emitter of the transistor Q3 is connected to Vout+ through the resistor R1, and the collector of the transistor Q3 is connected to Vout- through the resistor R2. The collector of the transistor Q3 is also connected to the gate of the MOS transistor Q2. The MOS transistor Q2 is an N-channel MOS transistor. The source of the MOS transistor Q2 is connected to the second output end of the power conversion circuit B1. The drain of the MOS transistor Q2 is connected to the signal input end of the ORing control circuit.

[0015] With the above switching power supply, after the switching power supply is turned off, if there is still electricity at the output end due to factors such as capacitors, the transistor Q3 is turned on due to the decrease in base potential, and the diode D1 is used to prevent the energy at the output end from entering the switching power supply. After the transistor Q3 is turned on, the MOS tube Q2 is turned on due to the increase in gate voltage. After the MOS tube Q2 is turned on, the control signal of the ORing control circuit B4 is directly pulled low, thereby quickly turning off the MOS tube Q1. It can be seen that this embodiment accelerates the shutdown of the ORing control circuit after the switching power supply is turned off, and provides a protection measure for the switching power supply to prevent energy backflow.

[0016] In some implementations, the switching power supply of this embodiment further includes a voltage regulator diode D2, the cathode of the voltage regulator diode D2 is connected to the gate of the MOS transistor Q2, and the anode of the voltage regulator diode D2 is connected to Vout-. The voltage regulator diode D2 is used to prevent the MOS transistor Q2 from being damaged by excessive voltage.

[0017] In some embodiments, the switching power supply of this embodiment further includes an error amplifier circuit B3 and a PWM control circuit B2, the input end of the error amplifier circuit B3 is connected to Vout+, the output end of the error amplifier circuit B3 is connected to the input end of the PWM control circuit B2, and the output end of the PWM control circuit B2 is connected to the feedback input end of the power conversion circuit B1.

[0018] In general, the switching power supply of this embodiment can prevent the energy at the load end from being fed back to the power end in time after the power supply is turned off, and can quickly and effectively cut off the energy transmission if there is reverse energy, thereby ensuring the safety of the switching power supply and other equipment.

[0019] For those skilled in the art, the above invention disclosure is only for example and does not constitute a limitation of the present invention. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and corrections to the present invention. Such modifications, improvements and corrections are suggested in the present invention, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of the present invention.

[0020] Although the present invention has been described with reference to the current specific embodiments, those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and various equivalent changes or substitutions may be made without departing from the spirit of the present invention. Therefore, any changes or modifications to the above embodiments within the spirit of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A switching power supply with an ORing control circuit, characterized in that: include: A power conversion circuit B1, wherein a first input terminal and a second input terminal of the power conversion circuit B1 are connected to Vin+ and Vin-, respectively, and the power conversion circuit B1 further comprises a first output terminal and a second output terminal, wherein the second output terminal is connected to Vout-; MOS transistor Q1, wherein the MOS transistor Q1 is an N-channel MOS transistor, and a source of the MOS transistor Q1 is connected to the first output end of the power conversion circuit B1, a drain of the MOS transistor Q1 is connected to Vout+, and a gate of the MOS transistor Q1 is connected to the signal output end of the ORing control circuit; A diode D1 and a resistor R3 are connected between the first output end and the second output end of the power conversion circuit B1, wherein the anode of the diode D1 is connected to the first output end of the power conversion circuit B1, the cathode of the diode D1 is connected to the first end of the resistor R3, and the second end of the resistor R3 is connected to the second output end of the power conversion circuit B1; The first end of the resistor R3 is also connected to the base of the transistor Q3, which is a PNP transistor, the emitter of the transistor Q3 is connected to the Vout+ through the resistor R1, and the collector of the transistor Q3 is connected to the Vout- through the resistor R2; The collector of the transistor Q3 is also connected to the gate of the MOS transistor Q2, which is an N-channel MOS transistor. The source of the MOS transistor Q2 is connected to the second output end of the power conversion circuit B1, and the drain of the MOS transistor Q2 is connected to the signal input end of the ORing control circuit.

2. The switching power supply with ORing control circuit according to claim 1, characterized in that: It also includes a voltage regulator diode D2, wherein the cathode of the voltage regulator diode D2 is connected to the gate of the MOS tube Q2, and the anode of the voltage regulator diode D2 is connected to Vout-.

3. The switching power supply with ORing control circuit according to claim 1, characterized in that: It also includes an error amplifier circuit B3 and a PWM control circuit B2, wherein the input end of the error amplifier circuit B3 is connected to the Vout+, the output end of the error amplifier circuit B3 is connected to the input end of the PWM control circuit B2, and the output end of the PWM control circuit B2 is connected to the feedback input end of the power conversion circuit B1.

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