Patent ID: 10742109

Abstract:
A controller (100) for a quasi-resonant (QR) flyback converter (200) having a switching element (210) operable at a switching frequency (F) is presented. The controller (100) is configured for repeatly: receiving, from the QR flyback converter (200), a controller input signal (ZC); determining a designated point of time at which the controller input signal (ZC) equals a threshold value (V_zcd), the designated point of time depending on a switching operation of the switching element (210); in response to determining the designated point of time, providing, to the QR flyback converter (200) and after a time delay, a controller output signal (G) for causing a further switching operation of the switching element (210); and modifying at least one of the threshold value (V_zcd) and the time delay (DT) by an amount, wherein modifying the at least one of the threshold value (V_zcd) and the time delay (DT) varies periodically, the period (TMF) of the modification period being the inverse of a modification frequency (MF).