MICROPROCESSOR CONTROLLED ELECTRONIC BALLAST

摘要

An electronic ballast includes an AC to DC converter (51, 52) for power fact or correction, a bulk capacitor (53, 120) for storing energy from the converter, and a microprocessor controlled, half-bridge inverter (54) including a series resonant, direct coupled output (35, 36). Input ports of the microprocessor (65) are coupled to several locations within the ballast to monitor the operation of the ballast or the operation of a gas discharge lamp coupled to the ballast. An analog voltage limiter (Q5) overrides the microprocessor to limit output voltage under fault conditions. A storage capacitor (121), connected in seri es with the bulk capacitor (120), stores energy at low voltage for powering the microprocessor. The microprocessor is programmed to provide lam p protection features, lumen maintenance, and a warm-up period for a lamp. The microprocessor is also programmed to meet the operati ng requirements of world markets and of different lamp types.