US 12,081,109 B2
Switching converter and control circuit thereof
Hongbin Lai, Hangzhou (CN); and Jianxin Wang, Hangzhou (CN)
Assigned to Silergy Semiconductor Technology (Hangzhou) LTD, Hangzhou (CN)
Filed by Silergy Semiconductor Technology (Hangzhou) LTD, Zhejiang (CN)
Filed on Dec. 6, 2021, as Appl. No. 17/542,723.
Claims priority of application No. 202011467221.1 (CN), filed on Dec. 14, 2020.
Prior Publication US 2022/0190704 A1, Jun. 16, 2022
Int. Cl. H02M 3/335 (2006.01); H02M 1/00 (2006.01)
CPC H02M 1/0058 (2021.05) [H02M 3/33507 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A control circuit for a switching converter having a main power switch and an auxiliary power switch, wherein the control circuit is configured to:
a) charge and discharge a junction capacitor of the main power switch during a turn-off period of the main power switch;
b) adjust a conduction time of the auxiliary power switch according to a difference between charged and discharged charge levels across the junction capacitor; and
c) a detection circuit configured to receive a sampling signal that represents a voltage change across the junction capacitor, and to generate a detection signal that represents the difference between the charged and discharged charge levels across the junction capacitor according to driving signal for the main power switch.