HID Lamp Electronic Ballast With Reduced Component Number

A reduced-component-number single-stage power-processing electronic ballast to drive high-intensity discharge lamps is presented in this paper. A dc-dc buck converter, which controls the current and the power of the lamp, a power factor preregulator based on a discontinuous conduction mode boost converter, and the inverter are combined in a boost integrated with buck rectifier/energy storage/dc-dc converter. It operates with a line-frequency square-wave current driving the lamp. The signals of the power stages are provided by a dedicated microcontroller. Ballast for sodium vapor lamps of 70 W without acoustic resonance was implemented, resulting in a
pf
= 0.97 with 22% total harmonic distortion and eta = 84%.