Microcontrolled electronic gear for low wattage metal halide (MH) and high-pressure sodium (HPS) lamps

This paper presents an electronic control gear for HID lamps that operates with a low frequency current inverter to drive the lamp, a DC-DC buck converter to control the current and the power of the lamp and a power factor pre-regulator based on discontinuous conduction mode boost converter. All signals of the power stages are provided by a dedicated microcontroller. An overview of the lamp operation phases and the strategies to avoid acoustic resonance are mentioned. A 70 W prototype without acoustic resonance and stroboscope effect was implemented. The approach can be easily extended for other rated power.