Transient detection of end of lamp life condition apparatus and method

摘要

A sensor system adapted to detect unwanted transients in the primary side of a luminous lamp load driving circuit and effect a change in operation of the driving circuit. A detection circuit is adapted to detect a transient, determine if it is an appropriate end-of-life lamp condition requiring action, and signal an inverter control circuit to provide for an adjustment or shut down of the load driving circuitry. The detection circuit is adapted to detect the transients across the direct current choke as repetitive transients occurring over a period of time. The inverter control circuit includes a negative voltage generator adapted to inhibit power flow into a transistor base inside the inverter. A modified start circuit is also provided with a restart inhibit circuit adapted to prevent the inverter from resuming normal operation after a shutdown condition has been detected.