Power Integrations, Inc.
Control of secondary switches based on secondary winding voltage in a power converter

Abstract:

A secondary controller including a control circuit coupled to a secondary switch of a power converter. The control circuit is coupled to receive a secondary switch voltage signal representative of the secondary switch, and turns ON the secondary in response in response to how many times the secondary switch voltage signal crosses below a turn on threshold to a limit set in a last half period. The control circuit turns OFF the secondary switch when the secondary switch voltage signal crosses above a turn off threshold.