HID Electronic Ballast with Auto-Switching of MH and HPS Lamps

램프 인식 기능을 가진 HID 전자식 안정기의 구현

This paper presents a microprocessor controlled electronic ballast for HID lamps, which gives automatic switching between MH and HPS lamps. Lamp identification is carried out by checking variation of lamp impedance at warm-up phase. Direct spread spectrum is done by applying 1 kHz triangular wave for removing acoustic resonance. This frequency modulation of 1 kHz gives also low EMI level. The microprocessor controls the voltage of DC-bus, the voltage of ignition pulses, the power of output. A 250W electronic ballast is implemented with ATmega16 CPU.