Standby lighting for lamp ballasts
AssigneeGeneral Electric Company
InventorsDidier Rouaud, Louis R. Nerone
Life of this patent
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Abstract
For safety reasons, industrial lighting fixtures are required to have backup lighting systems so that if the primary lights should fail, there will still be enough light to ensure safe maneuvering. Typically these backup lighting systems have their own power or drive source. The present application contemplates a lighting ballast circuit that is able to power a primary high intensity discharge (HID) lamp and is also able to power an auxiliary lamp in the event of temporary or permanent failure of the HID lamp.
Claims18
A lighting ballast comprising:
- a first inverter switch for providing power to a primary lamp during a first half-cycle of an alternating current lamp drive signal;
- a second inverter switch for providing power to the primary lamp during a second half-cycle of the lamp drive signal;
- a high voltage multiplier portion for boosting a signal applied to the primary lamp during a startup phase;
- a clamping portion for clamping voltages within the ballast to levels that the lamp can tolerate;
- a resonant portion that determines operating resonant frequency of the ballast;
- and,
- an integrated auxiliary lamp power portion for providing power to an auxiliary lamp if the primary lamp extinguishes.
A lighting fixture comprising:
- a first, primary lamp for performing a primary lighting function;
- a second, auxiliary lamp for performing an auxiliary lighting function in the event of failure of the primary lamp;
- and,
- a ballast inverter circuit that provides power to the primary lamp, and provides power to the auxiliary lamp when the primary lamp fails:
A method of powering a lamp fixture comprising:
- with a ballast inverter circuit, providing a high voltage ignition signal to an primary lamp, igniting the primary lamp;
- with the ballast inverter circuit, providing the primary lamp with a variable warm-up signal while the primary lamp is warming up;
- with the ballast inverter circuit, providing a steady state operating signal to the primary lamp after the primary lamp has warmed up;
- clamping voltages to non-damaging levels;
- and
- with the ballast inverter circuit, providing an operating signal for lighting and operating an auxiliary lamp.
Dependencies are inferred from the claim text.