Patent ID: 7876075

Claim:
A control circuit for a power converter, which is suitable for generating a stable voltage control signal to control ON/OFF of a power switch of a synchronous rectified buck converter with an inductor and an output capacitor, comprising: a difference generating circuit receiving an output voltage and a reference voltage of said synchronous rectified buck converter and acquiring a voltage difference between the output voltage and the reference voltage; a pulse modulation circuit generating a pulse width modulation signal according to said voltage difference; a time-optimal control (TOC) circuit detecting a change of said output voltage, creating a time-optimal control signal and a select signal when said change exceeds a default value, said time-optimal control signal being based on a voltage slew rate detected at the time of said change exceeding said default value to estimate a time interval T 1 from said change exceeding said default value being detected to a current of said inductor rising to a value the same as an output current of said synchronous rectified buck converter, being based on said time interval T 1 to figure out time intervals T 2 and T 3 for the time-optimal control signal maintaining at a reference level at said time intervals T 1 and T 2 and maintaining at another reference level at said time interval T 3 and generating said select signal at the time intervals T 1 , T 2 and T 3 ; and a multiplexer being based on said select signal to select said pulse width modulation signal or said time-optimal control signal being output as said stable voltage control signal.