US 11,799,379 B2
Control circuit, system and method for switched-mode power supply
Yanmei Guo, Shanghai (CN); Yihui Chen, Shanghai (CN); Haifeng Miao, Shanghai (CN); Yuehui Li, Shanghai (CN); Xiaoru Gao, Shanghai (CN); and Zhen Zhu, Shanghai (CN)
Assigned to SHANGHAI BRIGHT POWER SEMICONDUCTOR CO., LTD., Shanghai (CN)
Filed by SHANGHAI BRIGHT POWER SEMICONDUCTOR CO., LTD., Shanghai (CN)
Filed on Dec. 17, 2021, as Appl. No. 17/555,096.
Claims priority of application No. 202011625428.7 (CN), filed on Dec. 31, 2020.
Prior Publication US 2022/0209673 A1, Jun. 30, 2022
Int. Cl. H02M 3/335 (2006.01); H02M 1/00 (2006.01); H02M 3/158 (2006.01)
CPC H02M 3/33507 (2013.01) [H02M 1/0032 (2021.05); H02M 3/158 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A control circuit for a switched-mode power supply for driving a first switch in the switched-mode power supply to convert an input voltage into an output voltage, the control circuit comprising
an on-time control unit, which receives a first signal characterizing a switching frequency of the first switch and a second signal characterizing a current flowing through the first switch and responsively generates a signal indicative of a turn-off instant for the first switch,
wherein when a peak value of the current flowing through the first switch drops below a predefined value, the on-time control unit determines the turn-off instant for the first switch based on the first signal so that the switching frequency of the first switch is maintained at a target frequency.