Interleaved switching converter with quasi-resonant control and control method thereof

An interleaved switching converter comprising:

• a first and second interleaved switch;
• a first and second transformer;
• a first controller configured to control the first switch operate in quasi-resonant mode;
• a second controller configured to control the second switch, comprising:
• a phase-shifted control circuit configured provide a second ON control signal for turning-ON the second switch after the first switch is turned ON for a half switching period;
• a valley detection circuit configured to provide a valley pulse signal in response to one or more valleys of a voltage across the second switch during each OFF-time of the second switch;
• a peak signal generator configured to provide a peak signal based on the valley pulse signal, the second ON control signal and a threshold signal, and wherein the peak signal is adjusted when the voltage across the second switch is higher than a valley reference at the time the second switch is turned ON;
• and
• a peak comparison circuit configured to compare the peak signal with a current sensing signal indicative of a current flowing through the second switch and provide a second OFF control signal for turning-OFF the second switch.

A control method for an interleaved switching converter having a first and second interleaved voltage regulating circuit, the control method comprising:

• controlling a first switch of the first voltage regulating circuit operating in quasi-resonant mode;
• turning ON a second switch of the second voltage regulating circuit after the first switch is turned ON for a half switching period;
• generating a current sensing signal by detecting a current flowing through the second switch;
• generating a peak signal, wherein the peak signal is adjusted when a voltage across the second switch is higher than a voltage reference at the time the second switch is turned ON;
• and
• turning OFF the second switch when the current sensing signal increases to the peak signal.