Patent ID: 7345896

Claim:
A method of controlling a flyback power supply comprising: coupling a first power switch to a secondary side of a transformer of the flyback power supply, wherein the first power switch is coupled in series with a secondary side inductor of the transformer; coupling a second power switch on a primary side of the transformer to control at least a portion of current flow through a primary side inductor of the transformer; configuring a power supply controller to form a PWM control signal; coupling the PWM control signal to the second power switch to control the second power switch; coupling the PWM control signal from the primary side of the flyback power supply to the secondary side of the flyback power supply through an element other than the transformer to form a control signal that is representative of the PWM control signal and using the control signal to control the first power switch wherein the control signal enables the first power switch responsively to disabling the second power switch; and configuring the first switch to be disabled responsively to any one of the control signal, a value of an output voltage that is formed by the flyback power supply, and to sensing current flow in the secondary side of the flyback power supply decreasing to a first value.