Abstract: A switch coupled active forward converter comprising an AC power supply circuit for supplying AC power, a filtering circuit connected to the AC power supply circuit, for filtering an output current from the AC power supply circuit, an up converter connected to the filtering circuit, for generating a saw tooth wave signal in response to an output voltage from the filtering circuit, the saw tooth wave signal having a peak value following an input voltage to the AC power supply circuit when a switch ON operation is performed, a clamping circuit connected in common to the up converter, AC power supply circuit and filtering circuit, for clamping an output voltage from the up converter to a desired level, a transformer having a primary coil connected to the up converter, and an output circuit connected to a secondary coil of the transformer.

Abstract: The present invention provides a high quality power supply, and more particularly to an improved single-ended converter having the high power factor close to unity. In accordance with the present invention, the power supply comprises a power source, a low-pass filter, a rectifier including an inductor, a transformer primary coil, a transformer secondary coil, a ripple energy storing capacitor, a switching controller and an inductance element wound round a core where said transformer primary and secondary coils are wound. The inductance element being coupled to said rectifying means so that compensates a voltage applied to said inductor in said rectifying means with a voltage applied to said transformer primary coil.