Ballast for gas discharge lamps with shutdown of the filament heating
AssigneePatent-Treuhand-Gesellschaft fur Elektrische Glucklampen mbH
InventorsBernhard Schemmel, Michael Weirich
Life of this patent
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Abstract
An electronic ballast for discharge lamps with electrode filaments. The ballast contains a frequency-selective device, which suppresses an auxiliary heating current in the electrode filaments during operation of the lamp. Heating of the electrode filaments is possible only within a narrow frequency band.
Claims11
An electronic ballast for preheating, igniting and operating discharge lamps (LP), in which the electrode filaments of attached discharge lamps (LP) carry essentially the gas discharge current during operation, characterized in that the electronic ballast contains a frequency-selective device, which permits preheating of said electrode filaments only if the oscillation frequency of the electronic ballast is within a narrow frequency band, which is determined by the frequency-selective device.
A method for preheating, igniting and operating discharge lamps (LP) with an electronic ballast, characterized in that,
- for the preheating, the electronic ballast functions at an oscillation frequency which is within a frequency band in which a frequency-selective device of the electronic ballast permits preheating,
- for the ignition, the electronic ballast functions at an oscillation frequency at which a voltage that leads to ignition of the discharge lamps is generated at the discharge lamps,
- for the operation of the discharge lamps, the electronic ballast functions at an oscillation frequency which is within a frequency band in which the frequency-selective device of the electronic ballast suppresses an auxiliary heating current.
Dependencies are inferred from the claim text.