Patent ID: 7498750

Claim:
Method for driving a gas discharge lamp ( 10 ), comprising providing an AC supply voltage to a rectifier circuit ( 40 ), the rectifier circuit ( 40 ) outputting a double sided rectified voltage; providing a high frequency control signal to a high frequency bridge circuit ( 50 ); providing said double sided rectified voltage to said high frequency bridge circuit ( 50 ), the bridge circuit ( 50 ) outputting a high frequency bridge output voltage; and providing said bridge output voltage to a load circuit comprising the gas discharge lamp ( 10 ) and a resonant circuit ( 60 ); wherein the frequency of the bridge output voltage is controlled such that during steady-state operation of the gas discharge lamp ( 10 ) said resonant circuit ( 60 ) resonates to sweep up the voltage supplied to the gas discharge lamp ( 10 ) to a voltage higher than a predetermined ignition voltage each time the bridge output voltage is lower than a predetermined operation voltage.