US 12,149,177 B2
Converters and control methods of zero-voltage switching and quasi-resonant switching
Xuefeng Chen, Hangzhou (CN); and Hui Li, Hangzhou (CN)
Assigned to Hangzhou MPS Semiconductor Technology Ltd., Zhejiang (CN)
Filed by Hangzhou MPS Semiconductor Technology Ltd., Hangzhou (CN)
Filed on Sep. 29, 2022, as Appl. No. 17/956,442.
Prior Publication US 2023/0188046 A1, Jun. 15, 2023
Int. Cl. H02M 3/335 (2006.01); H02M 1/00 (2006.01); H02M 1/08 (2006.01)
CPC H02M 3/33515 (2013.01) [H02M 1/0009 (2021.05); H02M 1/08 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A controller used in a switching converter having a transformer, a first switch coupled to a primary winding of the transformer, a second switch coupled to an auxiliary winding of the transformer, the controller comprising:
an output feedback circuit configured to receive an output signal of the switching converter and generate an output feedback signal;
a hysteresis feedback circuit configured to generate a hysteresis feedback signal based on the output feedback signal;
a first comparison circuit configured to compare the hysteresis feedback signal with a ramp signal and generate a first comparison signal;
a second comparison circuit configured to compare the output feedback signal with the ramp signal and generate a second comparison signal;
a valley detection circuit configured to provide a valley pulse signal in response to one or more valleys of a voltage drop across the second switch during an OFF state of the second switch;
a turn-on control circuit configured to generate a target locked valley number based on the valley pulse signal, the first comparison signal, the second comparison signal and a current locked valley number, and further configured to generate a turning on control signal corresponding to the target locked valley number for turning ON the second switch; and
a primary turn-on control circuit configured to provide a primary turning on control signal to turn on the first switch after the second switch is turned off.