Synchronous Rectifying Switching Regulator, Control Circuit of Synchronous Rectifying Switching Regulator and Operation Control Method of Synchronous Rectifying Switching Regulator

摘要

A control circuit for a synchronous rectification switching regulator including an output terminal, a switching transistor, an inductor, and a synchronous rectification transistor has a control part configured to control switching of the switching transistor to charge the inductor to and set a voltage output from the output terminal to a predetermined voltage, which causes the synchronous rectification transistor to switch reversely to the switching transistor and discharge the inductor, and backflow prevention part configured to block a current flowing in the synchronous rectification transistor to prevent a backflow current that flows in a direction from the output terminal to the synchronous rectification transistor. The backflow prevention part detects a forward current and regulates timing to block the current flowing in the synchronous rectification transistor and to regulate a time period from blocking the current flowing in the synchronous rectification transistor to determining that the forward current is zero.