Control circuit for a synchronous rectifier

摘要

A control circuit includes an obtaining module (10), adapted to obtain a voltage signal produced by a reverse surge current when the reverse surge current appears on a primary side of a switch power circuit of a synchronous rectification circuit; a maintaining module (11), adapted to continuously output a first control signal in a preset first time period when the voltage signal is greater than a preset first voltage threshold; and a control module (12), adapted to control to switch off switch tubes of the secondary side of the switch power circuit of the synchronous rectification circuit according to the first control signal. Thus, a reverse current surge of the switch power circuit of the synchronous rectification circuit can be effectively suppressed, and the safety of a switch power supply of the synchronous rectification circuit can be effectively protected. The power supply device using the control circuit can effectively improve safety and reliability of the power supply.