Patent ID: 6731075
Filing Date: 2004-05-04
Classification: H05B,Y10S

Abstract:
An energy-efficient ballast for a discharge lamp comprising:a full-wave rectifier circuit configured to receive an alternating current input voltage and to provide a substantially direct current supply voltage; a plurality of semiconductor switches coupled to the substantially direct current supply voltage in an H-bridge configuration; and a feedback control circuit configured to control the plurality of semiconductor switches to provide an alternating current to the discharge lamp, wherein the feedback control circuit comprises: a transformer with a primary winding coupled between a first output of the plurality of semiconductor switches in the H-bridge configuration and a first cathode of the discharge lamp, wherein a plurality of secondary windings is coupled to respective control inputs of the plurality of semiconductor switches; a capacitor coupled between the first cathode and a second cathode of the discharge lamp; and an inductor coupled between the second cathode of the discharge lamp and a second output of the plurality of semiconductor switches in the H-bridge configuration.