Circuit for dimming gas discharge lamps without introducing striations
AssigneeLutron Electronics Co., Inc.
InventorsCharles R. Sullivan, Scott R. Jurell, David G. Luchaco
Life of this patent
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Abstract
A dimming circuit provides power from an ac source to a compact fluorescent lamp. The circuit generally includes a resonant circuit driven by a high-frequency switching inverter. The resonant circuit is essentially an ac current source and provides sinusoidal current to the lamp, which loads the resonant circuit in parallel. A small amount of dc current is simutaneously provided to the lamp. The resultant asymmetric current waveform flowing through the lamp substantially eliminates striation over a dimming range from about 100% to 1% of full light output.
Claims23
A control system for providing electrical power from a source to a gas discharge lamp, comprising:
- (a) means for providing symmetrical ac current to the electrodes of said lamp to strike and maintain an electric discharge therethrough;
- and
- (b) means for simultaneously providing dc current to said lamp electrodes;
- whereby an asymmetric current waveform is established in the lamp, substantially eliminating the occurrence of visible striations.
A control system for providing electrical power from a source to a pair of gas discharge lamps connected in series, comprising:
- (a) means for providing symmetrical ac current to the electrodes of said lamps to strike and maintain an electric discharge therethrough;
- and
- (b) means for simultaneously providing dc current to said lamp electrodes;
- whereby an asymmetric current waveform is established in the lamps, substantially eliminating the occurrence of visible striations.
Dependencies are inferred from the claim text.