General Electric Company

Gary C Seitz

George E Kiefer

Disclosed is a ballast circuit arrangement for a gas discharge lamp, which includes a ballast transformer arrangement receptive of an input power signal, having a winding and a serially connected ballast capacitor, and providing an output, ballast voltage that alternates in polarity during successive half cycles. A bypass capacitor is coupled to the winding of the ballast transformer for being charged by the ballast voltage. A voltage for driving the lamp exists on the bypass capacitor. The inventive arrangement includes a pulse transformer having a secondary winding in serial circuit with the lamp for impressing a high voltage, hot restrike starting pulse across the lamp. A hot restrike starting circuit is provided, comprising a starting capacitor coupled across the bypass capacitor, and a circuit for discharging the starting capacitor including a primary winding of the pulse transformer and a serially connected current switch. A circuit is provided to boost the lamp-driving voltage during operation of the hot restrike circuit, comprising a one-way current valve for substantially shorting out the ballast voltage during at least part of a half cycle of ballast voltage of a first polarity, whereby voltage across the ballast capacitor becomes additive to the voltage across the ballast transformer winding in the next, opposite polarity half cycle of ballast voltage so as to boost the lamp-driving voltage impressed across the lamp during such opposite polarity half cycle. Also included is circuitry for disabling the voltage boost circuit during normal lamp operation.

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Hendersonville, NC, United States of America

Gary C Seitz