Patent ID: 7795849
Filing Date: 2010-09-14
Classification: H02M,Y02B

Abstract:
1. A control circuit for a synchronous rectification switching regulator including: an output terminal configured to output a constant voltage to a load connected thereto; a switching transistor configured to perform switching according to a control signal; an inductor configured to be charged with an input voltage by the switching of the switching transistor; and a synchronous rectification transistor configured to perform switching according to a control signal to discharge the inductor, the control circuit comprising: a control part configured to control the switching of the switching transistor to set the voltage output from the output terminal to a predetermined voltage and cause the synchronous rectification transistor to switch reversely to the switching of the switching transistor; and a backflow prevention part configured to block a current flowing in the synchronous rectification transistor to prevent a backflow current flowing in a direction from the output terminal to the synchronous rectification transistor, wherein the backflow prevention part detects a forward current that flows when the synchronous rectification transistor discharges the inductor and regulates timing to block the current flowing in the synchronous rectification transistor to prevent an occurrence of the backflow current and to regulate a time period from blocking the current flowing in the synchronous rectification transistor to determining that the forward current is zero.