Patent ID: 9343969
Filing Date: 2016-05-17
CPC Classification: H02M,Y02B

Claim Text:
1. A control circuit for controlling a switching transistor and a synchronous rectifying transistor of a switching regulator, comprising: a bottom detection comparator configured to assert an on signal when a feedback voltage depending on an output voltage of the switching regulator decreases to a predetermined reference voltage; an input terminal to which an input voltage of the switching regulator is input; an output voltage detection terminal to which the output voltage of the switching regulator is input; a timer circuit configured to generate an off signal asserted after lapse of on-time having a length depending on the input voltage input from the input terminal and the output voltage input from the output voltage detection terminal after the on signal is asserted, the timer circuit being connected to the input terminal and the output voltage detection terminal; a zero current detector configured to assert a zero current detection signal when current flowing into the synchronous rectifying transistor decreases to a predetermined threshold value after the off signal is asserted; and a driving circuit configured to receive the on signal, the off signal and the zero current detection signal, and (i) turn on the switching transistor and turn off the synchronous rectifying transistor when the on signal is asserted, (ii) turn off the switching transistor and turn on the synchronous rectifying transistor when the off signal is asserted, and (iii) turn off the switching transistor and the synchronous rectifying transistor when the zero current detection signal is asserted.