Abstract: The invention provides an ignition device for a gas discharge lamp. The device comprises a voltage multiplier which is connected to an AC mains source. A pulse generator is connected to the voltage multiplier and produces a trigger pulse when the source voltage exceeds a predetermined threshold. The output of the pulse generator is applied to a resonant network including a step-up transformer, which applies high voltage ignition pulses to the lamp. A delay circuit synchronizes the ignition pulses with the peaks of the AC mains waveform.

Abstract: A controller for a gas discharge lamp supplies the lamp with a direct current which has been pulse-width modulated at a high frequency via a smoothing circuit and a polarity inversion circuit. The polarity inversion circuit periodically reverses the polarity of current supplied to the lamp to equalize electrode wear in the lamp. The controller senses the lamp voltage, current, power or other characteristics and maintains at least one operating parameter of the lamp, for example the lamp current, constant. A warm up cycle allows this parameter to be adjusted for fast starting of the lamp.