Patent ID: 7075254

Claim:
An electronic ballast for driving a gas discharge lamp, comprising: a rectifier stage for receiving an alternating current (AC) input voltage from an AC supply to produce a rectified voltage having a peak voltage amplitude; a boost converter stage for receiving the rectified voltage and for providing a direct current (DC) bus voltage having a DC magnitude; the boost converter stage having an on state, in which the DC magnitude of the DC bus voltage is greater than the peak voltage amplitude of the rectified voltage, and an off state, in which the DC magnitude of the DC bus voltage is substantially equal to the peak voltage amplitude of the rectified voltage; an inverter output stage for converting the DC bus voltage to a high-frequency AC output voltage to drive the lamp; further comprising: a control stage for receiving a desired light level signal representative of a desired light level of the lamp and for providing an output control signal to said boost converter stage; wherein the boost converter stage changes between the on state and the off state dependent on the desired light level signal.