Patent ID: 7515442

Claim:
A secondary side power supply controller for regulating a secondary voltage of a secondary winding of a power supply comprising: a synchronizing circuit configured to receive an input signal representative of a primary side switching drive signal used to control a power switch of a primary side of the power supply and responsively provide a sync signal having an active state representative of the primary side switching drive signal; a secondary side switching control section configured to receive a feedback signal that is representative of the secondary voltage and receive the sync signal and responsively form a switching control signal operable to control a secondary side power switch for regulating the secondary voltage, the secondary side power switch coupled in series with the secondary winding; and control logic configured to receive the sync signal and the switching control signal and responsively form a switching drive signal operable to control the secondary side power switch wherein the control logic is configured to enable the secondary side power switch independently of a state of the primary side switching drive signal at least after the secondary voltage is less than a first value.