A driving circuit for one or more gas discharge lamps (102, 104, 106) having heatable filaments (102A&B, 104A&B, 106A&B) includes: a self-oscillating, series-resonant oscillator (196, 198, 178, 180) for producing a high-frequency output voltage for application to the lamps via an output-coupling transformer...http://www.google.ca/patents/US5144195?utm_source=gb-gplus-sharePatent US5144195 - Circuit for driving at least one gas discharge lamp
