A study on electronic ballast for metal halide lamps with adaptive starting

The metal halide lamps make them suitable of use in illumination systems for outdoor spaces in the long times. They are now widely used in many applications including commercial lighting due to their attracting properties such as good color, rendering and high efficiency. Over the past few years, a considerable number of studies have been conducted on the electronic ballast with hot restarting. But, very few attempts have been made at adaptive ignition method according to lamp tube state. In this paper we propose electronic ballast for metal halide lamps with an igniter for adaptive starting. The proposed electronic ballast can generate a different ignition voltage according to the arc tube state. When the temperature of arc tube is low the ballast is provided to lamp tube about 2 kV/spl sim/3 kV ignition voltage by igniter using LC resonant tank. But when the temperature of arc tube is high, the ballast supplies to the lamp about 18 kV ignition voltage by using external igniter with spark gap and high voltage transformer.