US 12,143,023 B2
Drive scheme for secondary-controlled active clamp flyback (ACF) mode
Rajesh Karri, Visakhapatnam (IN); Arun Khamesra, Bangalore (IN); and Hariom Rai, Bangalore (IN)
Assigned to Cypress Semiconductor Corporation, San Jose, CA (US)
Filed by Cypress Semiconductor Corporation, San Jose, CA (US)
Filed on May 19, 2022, as Appl. No. 17/748,616.
Prior Publication US 2023/0378877 A1, Nov. 23, 2023
Int. Cl. H02M 3/335 (2006.01); H02M 1/08 (2006.01)
CPC H02M 3/33569 (2013.01) [H02M 1/08 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A secondary-side controlled alternating current to direct current (AC-DC) converter comprising:
a primary-side field effect transistor (FET);
a primary-side controller;
a secondary-side FET;
a transformer coupled to the primary-side FET and the secondary-side FET;
an active clamp FET coupled to the primary-side FET, wherein the active clamp FET is disposed on a primary side of the transformer;
a secondary-side controller coupled to the transformer, wherein the secondary-side controller is configured to control the active clamp FET and the primary-side FET across a same galvanic isolation barrier; and
a dual-level pulse transformer coupled between the active clamp FET and the secondary-side controller to provide the same galvanic isolation barrier between the secondary-side controller and the primary-side controller;
wherein the secondary-side controller is to send a first pulse at a first signal level to control the active clamp FET via the dual-level pulse transformer, wherein the secondary-side controller is to send a second pulse at a second signal level to control the primary-side FET via the dual-level pulse transformer, and wherein the second signal level is different than the first signal level.