US 11,901,813 B2
Systems and methods for valley locking related to quasi-resonant switching power supplies
Penglin Yang, Shanghai (CN); and Yuan Lin, Shanghai (CN)
Assigned to On-Bright Electronics (Shanghai) Co., Ltd., Shanghai (CN)
Filed by ON-BRIGHT ELECTRONICS (SHANGHAI) CO., LTD., Shanghai (CN)
Filed on Dec. 27, 2021, as Appl. No. 17/562,805.
Claims priority of application No. 202011576478.0 (CN), filed on Dec. 28, 2020.
Prior Publication US 2022/0209656 A1, Jun. 30, 2022
Int. Cl. H02M 3/335 (2006.01); H02M 3/00 (2006.01); H02M 1/00 (2006.01)
CPC H02M 3/01 (2021.05) [H02M 1/0003 (2021.05); H02M 3/335 (2013.01); H02M 3/33507 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A controller for a quasi-resonant switching power supply, the controller comprising:
a valley detector configured to receive a voltage signal, detect one or more voltage valleys of the voltage signal in magnitude, and generate a detection signal representing the detected one or more voltage valleys;
a valley-locking controller configured to receive one or more signals, generate a mode control signal that indicates a selected valley-locking mode based at least in part on the one or more signals, select from the detected one or more voltage valleys, one or more valleys that correspond to the selected valley-locking mode, and generate a valley control signal indicating the one or more selected valleys; and
a gate driver configured to generate a drive signal based on at least information associated with the valley control signal and change the drive signal from a first logic level to a second logic level to start multiple switching cycles in response to the one or more selected valleys;
wherein, in the selected valley-locking mode,
the valley-locking controller is further configured to select one or more nth valleys of the voltage signal and one or more (n+1)th valleys of the voltage signal as the one or more selected valleys, n being a positive integer; and
the gate driver is further configured to:
start one or more first switching cycles of the multiple switching cycles at the one or more nth valleys of the voltage signal respectively; and
start one or more second switching cycles of the multiple switching cycles at the one or more (n+1)th valleys of the voltage signal respectively.