Patent ID: 7015652

Claim:
An electronic ballast protection and control circuit, comprising: an end of lamp life sensing and control circuit adapted to sense an end of lamp life condition in a gas discharge lamp load connected to an electronic ballast and to cause the electronic ballast to enter an end of lamp life protected state when the end of lamp life condition occurs, wherein the end of lamp life sensing and control circuit is adapted to be capacitively coupled across an output of the electronic ballast, to sense the end of lamp life condition by sensing a peak-to-peak voltage that develops across the gas discharge lamp load when the end of lamp life condition occurs, to generate an end of lamp life control signal when the peak-to-peak voltage exceeds a predetermined end of lamp life reference voltage, and adapted to set the predetermined end of lamp life reference voltage using an end of lamp life reference component included in the end of lamp life sensing and control circuit, and wherein the end of lamp life sensing and control circuit is adapted to sense DC rectification and excessively high AC voltage end of lamp life conditions.