Discharge lamp operating circuit
AssigneeGeneral Electric Company
InventorDavid W. Knoble
Life of this patent
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Abstract
Color properties of high pressure sodium vapor discharge lamps are improved by disclosed operating circuit for applying pulsed direct current to the lamp. The circuit comprises a direct current supply circuit, a transistor switch in series with the lamp and the primary of a transformer connected across the supply circuit, a diode in series with the secondary of the transformer connected across the supply circuit, and SCR switch connected across the secondary of the transformer, and a control circuit connected to the switches for applying DC pulses to the lamp at a predetermined repetition rate and duty cycle. The circuit produces pulse waveforms which provide substantial color improvement in the lamp and makes efficient use of the energy supplied from the power source.
Claims17
A lamp operating circuit comprising, in combination, a direct current power source, a first branch including first controlled switch means across said power source, a second branch including unidirectional conducting means across said power source, a transformer having a primary winding in said first branch in series with said first controlled switch means and a secondary winding in said branch in series with said unidirectional conducting means, means for connecting a gaseous discharge lamp to said power source in series with at least one of said branches, second controlled switch means coupled to said secondary winding for substantially stopping current flow to said unidirectional conducting means and for storing magnetic energy in said transformer while said second controlled switch means is on, and control means coupled to said first and second controlled switch means for repetitively and sequentially operating the same at predetermined intervals, whereby DC pulses may be applied to the gaseous discharge lamp for operation thereof.
Dependencies are inferred from the claim text.