Flyback converter with improved synchronous rectification

Abstract

A flyback converter circuit in accordance with an embodiment of the present application includes a DC input operable to receive a DC voltage from a DC voltage source, a transformer including a primary coil and a secondary coil, a primary switch operable to selectively connect the primary coil to the DC input, a controller operable to provide a control signal to turn the primary switch ON and OFF, wherein the primary coil is connected to the DC input when the primary switch is ON, a delay device operable to delay an ON pulse of the control signal provided to the primary switch such that the primary switch is turned on after a delay of a predetermined period of time and a secondary switch connected in series with a capacitor and controlled by the control signal from the controller, wherein the secondary switch and the capacitor are connected in parallel with the primary switch. The control signal from the controller turns the secondary switch ON during the delay, such that a transient is induced in the primary coil before the primary switch is turned ON.