A novel circuit of a single-switch electronic ballast with a boost-type resonant converter applied to HID lamps

In this paper a novel type of solid-state electronic ballast for an HID (high intensity discharge) lamp is presented. The key feature of the circuit topology is the application of a boost-type resonant converter. Recent developments in HID lamps have increasingly been attracting interest due to their highly efficient operation and excellent color characteristics. These lamps are suitable for various applications, including automobile head-lamps and back lamps for projectors. The HID lamps exhibit negative-resistance characteristics in the operating regions, and lamp resistance varies as the time proceeds. Consequently, ballasts are needed, and high voltage is also needed to ignite lighting for the HID lamps. The proposed circuit is very simple. This proposed circuit can generate sufficiently high voltage pulses for the HID lamp without an additional igniter circuit. A 70 W metal-halide lamp (an HID lamp) is used in this circuit. The design and performance of this proposed circuit are described in this paper. Based on the theoretical and experimental results, the proposed ballast is suitable for the HID lamps.