Anti-reverse connection and current back-feeding circuit

Abstract

The invention discloses a reverse connection and current backfeed prevention circuit, which comprises a voltage input end for receiving input voltage, a voltage output end for outputting voltage to a back-end circuit, a control circuit for receiving voltage and outputting a first control signal or a second control signal, a switching circuit and an output circuit, wherein the switching circuit is conducted when the first control signal is received, and is cut off when the second control signal is received; when a first input end is connected with a positive electrode of a power supply and a second input end is connected with a negative electrode of the power supply, the switching circuit is conducted and the power supply outputs voltage to the back-end circuit; and when the first input end is connected with the negative electrode of the power supply and the second input end is connected with the positive electrode of the power supply or the power supply connected with the first input end and the second input end is in short circuit, the output circuit pulls down the voltage of the control circuit, the switching circuit is cut off and the voltage and backfeed current of the second input end are not provided to the back-end circuit, so that the cost is reduced and the circuit can be timely cut off while the high-power power supply requirement is met, and the damage of reverse connection of the power supply or current backfeed to the power supply and the back-end circuit is avoided.

Description

technical field [0001] The invention relates to the technical field of power supplies, in particular to an anti-reverse connection and current reverse feeding circuit. Background technique [0002] Low-power DC power supplies generally use diodes as anti-reverse connection or current reverse-injection circuits to prevent power supply and back-end circuits from being damaged by reverse-connection or current reverse-injection circuits. However, as the power increases, the loss of diodes will increase. , seriously affecting the efficiency of the power supply. High-power power supplies basically use metal oxide field effect transistors (MOSFETs) or integrated chips as the anti-reverse connection circuit, which has less loss, but the cost of integrated chips is higher, and the cost of MOSFETs is lower. Turning off the MOSFET may lead to abnormal operation of the power supply, and even the risk of damage. The current backfeeding of this circuit mainly comes from two aspects. One ...

AI Technical Summary

Problems solved by technology

[0002] Low-power DC power supplies generally use diodes as anti-reverse connection or current back-feeding circuits to prevent damage to the power supply and back-end circuits due to reverse power connection or current back-feeding. However, as the power increases, the loss of the diode will increase. , seriously affects the efficiency of the power

High-power power supplies basically use metal oxide field effect transistors (MOSFET) or integrated chips as the anti-reverse connection circuit, which has less loss, but the cost of integrated chips is higher, and the cost of MOSFETs is lower. Turning off the MOSFET may lead to abnormal operation of the power supply, and even the risk of damage. The current backfeeding of this circuit mainly comes from two aspects. One is the sudden short circuit of the power supply, and the input capacitor will be quickly discharged through the input terminal, thus forming a current backfeed Sinking, in the bridge current synchronous rectification, it may cause the drain-source voltage of the synchronous rectification MOSFET to increase sharply, damage the MOSFET, and may also damage the power supply; the other is the negative surge (-48V to the voltage input circuit surge) There may be a situation of current backfeeding, resulting in power failure

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