Patent ID: 7750580

Claim:
A ballast for operating a gas discharge lamp, comprising: a power factor correction circuit and an energy storage capacitor coupled to the output thereof, the power factor correction circuit being configured to draw current from an AC power source during substantially more than half of the cycle of the input AC voltage waveform when substantially full power is being supplied thereto, the power factor correction circuit comprising energy transfer elements for extracting energy from the AC power source via an input rectifier, even when the peak voltage of the AC voltage waveform is substantially lower than the voltage of the energy storage capacitor, and transferring the energy to the energy storage capacitor a sufficient number of times during each cycle of the input AC voltage waveform, such that the energy storage capacitor remains substantially fully charged during steady-state ballast operation; an inverter coupled to the power factor correction circuit, the energy storage capacitor providing DC power for the inverter; and a starting circuit coupled for receiving AC power from the inverter and initiating a discharge in the lamp.