US 12,407,264 B2
Resonant flyback power converter and switching control circuit and method thereof
Kun-Yu Lin, Hsinchu (TW); Ta-Yung Yang, Hsinchu (TW); Yu-Chang Chen, Hsinchu (TW); Hsin-Yi Wu, Hsinchu (TW); Fu-Ciao Syu, Hsinchu (TW); and Chia-Hsien Yang, Hsinchu (TW)
Assigned to Richtek Technology Corporation, Hsinchu (TW)
Filed by Richtek Technology Corporation, Hsinchu (TW)
Filed on Apr. 10, 2023, as Appl. No. 18/298,340.
Claims priority of provisional application 63/379,771, filed on Oct. 17, 2022.
Claims priority of provisional application 63/379,020, filed on Oct. 11, 2022.
Claims priority of provisional application 63/378,765, filed on Oct. 7, 2022.
Prior Publication US 2024/0120844 A1, Apr. 11, 2024
Int. Cl. H02M 3/335 (2006.01); H02M 1/00 (2006.01); H02M 1/32 (2007.01); H02M 3/00 (2006.01)
CPC H02M 3/33571 (2021.05) [H02M 1/0041 (2021.05); H02M 1/0058 (2021.05); H02M 1/32 (2013.01); H02M 3/01 (2021.05); H02M 3/33592 (2013.01); H02M 1/0009 (2021.05); H02M 1/0048 (2021.05); H02M 1/0054 (2021.05)] 19 Claims
OG exemplary drawing
 
1. A resonant flyback power converter, comprising:
a first transistor and a second transistor which are configured to form a half-bridge circuit;
a current-sense device, coupled to the half-bridge circuit and configured to sense a primary switching current of the half-bridge circuit to generate a current-sense signal;
a transformer and a resonant capacitor which are connected in series and are coupled to the half-bridge circuit; and
a switching control circuit configured to operably generate a first driving signal and a second driving signal to control the first transistor and the second transistor respectively for switching the transformer and the resonant capacitor to generate an output voltage;
wherein during a turn-on period of the first driving signal, the switching control circuit controls the half-bridge circuit to generate a positive current of the primary switching current to magnetize the transformer and charge the resonant capacitor;
wherein during a turn-on period of the second driving signal, the switching control circuit controls the half-bridge circuit to generate a negative current of the primary switching current to discharge the resonant capacitor;
wherein the switching control circuit senses the current-sense signal to turn off the first transistor when a level of the positive current exceeds a positive-over-current threshold, and/or, to turn off the second transistor when a level of the negative current exceeds a negative-over-current threshold.