ELECTRONIC BALLAST FOR DISCHARGE LAMP, LIGHTING FIXTURE EMPLOYING THAT ELECTRONIC BALLAST, AND LIGHTING SYSTEM EQUIPPED WITH THAT LIGHTING FIXTURE

摘要

An electronic ballast for operating at least one discharge lamp, comprising a chopper for applying a constant DC voltage, an inverter arranged to convert the DC voltage from the chopper into a high frequency AC voltage, and a resonance circuit for applying the high frequency AC voltage while resonating to at least one discharge lamp thus generating a resonant AC voltage for operating it. The electronic ballast further comprises a power regulation circuit arranged to specify a target power corresponding to a power request determined by at least one discharge lamp, and an inverter controller for sustaining the output power to the discharge lamp at the target power level by varying the switching frequency of the inverter by feedback control based on a resonance current flowing through the resonance circuit.