Switch power supply output overvoltage protection circuit

Abstract

The invention discloses a switch power supply output overvoltage protection circuit comprising an overvoltage detection unit, a protection signal generation unit and a pulse width modulation unit, wherein the overvoltage detection unit is used for judging whether the switch power supply output is in overvoltage according to the output sampling voltage of the switch power supply; the protection signal generation unit is used for generating the protection signal when the judgement result of the overvoltage detection unit is switch power supply output overvoltage; and the pulse width modulation is used for controlling pulse driving output and lowering the output voltage of the switch power supply according to the protection signal. In the invention, the overvoltage detection unit is used forjudging whether the switch power supply output is in overvoltage; when the switch power supply output is in overvoltage, the protection signal generation unit generates the protection signal; the pulse width modulation unit controls the pulse driving output according to the protection signal, lowers the output voltage of the switch power supply, and realizes the overvoltage protection of the switch power supply, thus obtaining the effect of high dynamic respond speed of the protection circuit, high control precision and in-time circuit protection and avoiding fault expansion.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to an output overvoltage protection circuit of a switching power supply. Background technique [0002] With the rapid development of power electronics technology, the relationship between power electronic equipment and people's work and life is becoming increasingly close, and electronic equipment is inseparable from a reliable power supply. Due to its small and light features, switching power supplies have entered the fields of various electronic and electrical equipment. Program-controlled switches, communications, electronic testing equipment power supplies, control equipment power supplies, etc. have widely used switching power supplies, which has promoted the rapid development of switching power supply technology. . A switching power supply is a power supply that uses modern power electronics technology to control the time ratio of switching transistors on and off to...

AI Technical Summary

Problems solved by technology

[0004] However, the response speed of the power system is slow in the case of large load changes and abnormal feedback, and the protection cannot be realized in a timely and reliable manner under fault conditions.

When the power system has large load changes and abnormal feedback, there will be an instantaneous high voltage on each output voltage of the switching power supply, causing the load to burn out due to overvoltage

Images