Patent ID: 7187136

Claim:
A ballast for powering a high intensity discharge lamp, comprising: a rectifier circuit adapted to receive an alternating current line voltage; an active power factor corrector (PFC) circuit coupled to the rectifier circuit, and operable to provide an output current and an output voltage; an inverter section coupled to the active PFC circuit; a power control circuit means for providing a power control signal to the active PFC circuit in dependence on the output voltage and the output current of the active PFC circuit, wherein the power control circuit means is coupled between the inverter section and the active PFC circuit; and wherein the active PFC circuit comprises: a boost/flyback converter coupled between the rectifier circuit and the inverter section; and a boost/flyback control circuit means for controlling operation of the boost/flyback converter in dependence on the power control signal provided by the power control circuit means, wherein the boost/flyback control circuit means is coupled between the boost/flyback converter and the power control circuit means.