CONTROL CIRCUIT FOR SYNCHRONOUS RECTIFIER-TYPE DC-DC CONVERTER, SYNCHRONOUS RECTIFIER-TYPE DC-DC CONVERTER AND CONTROL METHOD THEREOF

摘要

To provide a control circuit for a synchronous rectifier-type DC-DC converter, a synchronous rectifier-type DC-DC converter and a control method thereof in which, in a light load state and a no-load state, an output voltage can be dropped to thus prevent an overshoot state from continuing. A synchronous rectifier-type DC-DC converter 10 and a control circuit 20A thereof comprising a first switching element FET1 that is made conductive when power is accumulated in an induction element L1, and a second switching element FET2 that is made conductive when power accumulated in induction element L1 is supplied to a load, also comprises a detecting unit COMP2 that detects that a value of an output voltage VOUT of the synchronous rectifier-type DC-DC converter 10A is a predetermined voltage value that is higher than a target voltage value, and control units COMP1 and OR1 that maintain the second switching element FET2 in a conductive state after discharge of the power accumulated in the induction element L1 is finished, based on the detection results of the detecting unit COMP2.