Patent ID: 7649757
Filing Date: 2010-01-19
Classification: H02M,Y02B

Abstract:
1. A leakage-inductance energy recycling circuit for a flyback converter, wherein the flyback converter comprises a transformer having a primary winding and a secondary winding, the primary winding is electrically connected to a power transistor under the control of a controller, and the controller outputs a pulse width modulation signal to control ON or OFF of the power transistor, so as to enable the transformer to convert a DC input voltage into a DC output voltage through the ON or OFF of the power transistor, the leakage-inductance energy recycling circuit comprising: a clamping circuit, electrically connected to the primary winding of the transformer, for restricting a voltage across the power transistor at a predetermined voltage; an energy storage circuit; and a switch, electrically connected between the clamping circuit and the energy storage circuit, wherein when the switch is turned off, the clamping circuit receives and stores the leakage-inductance energy of the primary winding of the transformer; when the switch is turned on, the energy stored in the clamping circuit is released into the energy storage circuit via the switch.