A digital 70W metal halide lamp electronic ballast with ZVS inverter

This paper presents a new kind of digital 70W metal halide lamp electronic ballast. Dual-buck half bridge with high efficiency and reliability is chosen here, with this topology, ZVS can be achieved easily. The AVR special microcontroller for HID ballast is used to raise control performance, and low-frequency square-wave control method is adopted to avoid acoustic resonance. Experimental results show that metal halide lamp works steadily without acoustic resonance, harmonic content can be controlled below 10% and efficiency of the ballast can be higher than 92%.