Investigation on transient and steady-state characteristics with electronic ballast of automotive HID lamps

An electronic ballast for driving automotive HID lamps is presented. The circuit topology is composed of a flyback converter, a full-bridge inverter, and a two-stage step-up igniter. A prototype was developed and tested on a 35 W lamp with a 12 V input voltage. To avoid acoustic resonance, the full bridge inverter is operated at 400 Hz and provides a square-wave voltage source to the lamp. The transient and steady state characteristics of the tested HID lamps are measured and analyzed, and a clarity first-order expression of the lamp model is obtained.