The protection of the electronic ballasts for HID lamps

The electronic ballasts for HID lamps need a protection circuit to prevent from high voltage and/or current stresses on circuit components in case that the HID lamps or the electronic ballasts are in faults. In this paper, a universal protection circuit is proposed for the electronic ballast for HID lamps. The simple protection circuit offers: short circuit, open circuit, startup failure, hot- and old-lamps are protected in abnormal operation, high efficiency and nearly no loss in normal operation. The protection circuit is adapted to various types of electronic ballasts for different kinds of HID lamps. A prototype with the novel circuit for 250 W HPS lamp is successfully developed and experimental result verified the design properly.