Universal high intensity discharge electronic starter

摘要

An electronic starter for high intensity discharge devices, such as mercury vapor, high pressure sodium, and metal halide lamps. The present invention includes voltage controlled oscillator with a resonant frequency that is determined by the direct voltage applied and by a resonance circuit that includes the high intensity device as part of the resonance circuit. A higher frequency of oscillation is present upon start-up before the device is ionized of approximately 300 kilohertz. After that, the high intensity device shunts out one of the capacitance reactive elements lowering the circuit's Q and maintaining an operating frequency that oscillates between 20 and 100 kilohertz. The inductive element acts as a current limiting device and a protection circuit is provided to monitor the voltage across the lamp and to disable the oscillator if abnormal conditions are detected including removal of the lamp.