Low-frequency square-wave-driven automotive HID lamp ballast without acoustic resonance

This paper proposes a novel two-stage electronic ballast used to supply automotive high-intensity-discharge (HID) lamps with low-frequency square-wave sources. The ballast is composed of a boost-flyback converter with two output windings plus cascaded voltage doublers to boost up the 12 V input voltage to a high DC voltage level of 400 V, and a high-frequency combined with low-frequency square-wave-driven half-bridge inverter for supplying low-frequency square-wave sources to the lamp without incurring acoustic resonance. Analysis of operational modes for the presented ballast and experimental results of a prototype ballast for providing one 35 W automotive HID lamp with a 12 V input DC voltage are demonstrated.