Abstract: A control circuit for use in a power converter has a synchronous rectifier for producing substantially direct current, including a sensor for sensing a characteristic of the power converter; detection circuitry capable of using the characteristic to develop a control signal for controlling the power converter; and synchronous rectifier control circuitry connected to the detection circuitry wherein the control circuitry is adapted to modify a duty cycle of the power converter as a function of the control signal thereby to turn off a freewheel switch of the synchronous rectifier before turning off a forward switch of the synchronous rectifier during a reverse current period.