Switching power supply and overvoltage protection circuit thereof

Abstract

The invention is suitable for the field of power supplies and provides a switching power supply and an overvoltage protection circuit thereof. The switching power supply comprises a power conversion unit and a switching power supply overvoltage protection circuit. The switching power supply overvoltage protection circuit comprises a power conversion control unit and an overvoltage protection unit. The overvoltage protection unit comprises a voltage detection and power supply management module, a feedback module, a power supply switch module and a time-delay clamping module. In the embodiment of the invention, when the output voltage of the power conversion unit of the switching power supply sharply rises to a value exceeding an overvoltage point, the voltage detection and the power supply management module feeds the output voltage back to the control end of the power conversion control unit, the time-delay clamping module reduces the rate of rise of the output voltage at the control end, the power conversion unit reduces the rate of rise of the output voltage of the power conversion unit, the voltage detection and power supply management module can conduct overvoltage protection in time even through time delay exists and therefore the switching power supply or a load can be prevented from being burned out.

Description

technical field [0001] The invention belongs to the field of power supplies, in particular to a switching power supply and an overvoltage protection circuit thereof. Background technique [0002] Switching power supply is a kind of power supply that uses modern power electronic technology to control the time ratio of switching on and off to maintain a stable output voltage. Switching power supply is widely used in industrial automation control, military equipment, scientific research equipment, LED lighting, industrial control equipment, Communication equipment, power equipment, instrumentation, medical equipment and semiconductor refrigeration and heating and other fields. [0003] In a switching power supply, overvoltage protection is of great significance to its normal operation. Generally, multi-output switching power supplies (such as ordinary household desktop computer power supplies) use power management chips to control overvoltage protection. The power management c...

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Problems solved by technology

[0004] The purpose of the embodiments of the present invention is to provide a switching power supply overvoltage protection circuit, which aims to solve the problem that the existing switching power supply overvoltage protection circuit has a delay when the power management chip suddenly appears, and it is too late to realize the overvoltage protection. The problem

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