High power density electronic ballast for HID lamps

A high power density electronic ballast circuit for high intensity discharge (HID) lamp is proposed. Approaches to achieve high power density are studied. Topologically, the zero-voltage-switching quasi-square-wave concept is adopted when developing the high frequency high efficiency DC/DC front-end converter for the ballast based on the semiconductor loss analysis. On the other hand, a PCB level packaging method is proposed to deal with the thermal related issues, which further improves the power density of the system. A prototype is developed, with a maximum efficiency of 93.3% and the power density of 38.7 W/inch/sup 3/.