US 12,009,754 B2
Switching power converter with reduced voltage switching of the primary switch
Ajay Karthik Hari, Scottsdale, AZ (US); and Dhruv Chopra, Gilbert, AZ (US)
Assigned to SEMICONDUCTOR COMPONENTS INDUSTRIES, LLC, Scottsdale, AZ (US)
Filed by SEMICONDUCTOR COMPONENTS INDUSTRIES, LLC, Phoenix, AZ (US)
Filed on Oct. 1, 2021, as Appl. No. 17/449,680.
Claims priority of provisional application 63/198,200, filed on Oct. 2, 2020.
Prior Publication US 2022/0109374 A1, Apr. 7, 2022
Int. Cl. H02M 3/335 (2006.01); H02M 1/088 (2006.01); H02M 1/34 (2007.01); H02M 1/00 (2006.01)
CPC H02M 3/33592 (2013.01) [H02M 1/088 (2013.01); H02M 1/348 (2021.05); H02M 3/33507 (2013.01); H02M 1/0009 (2021.05); H02M 1/0058 (2021.05)] 20 Claims
OG exemplary drawing
 
1. A method of operation a switching power converter, comprising:
activating, during a first switching period, a primary switch coupled to a primary winding of a transformer of a flyback topology, the activating induces a positive current in the primary winding;
deactivating the primary switch and activating a secondary switch coupled to a secondary winding of the transformer, the activating the secondary switch during the first switching period and for a duration selected based on a signal indicative of negative current from a prior switching period, and the activating the secondary switch results in a positive current through the secondary winding followed by a negative current through the secondary winding;
discharging capacitance of the primary switch by a negative current in the primary winding responsive to the negative current in the secondary winding; and then
activating the primary switch during a second switching period subsequent to the first switching period,
wherein the first switching period begins after the prior switching period ends.