FREQUENCY MODULATION METHOD AND DEVICE FOR HIGH INTENSITY DISCHARGE LAMP

摘要

An electronic control gear for a HID lamp receives an input signal for operating the lamp and frequency modulates the input signal to generate a frequency modulated output signal that drives an arc of the lamp. The frequency modulation of the output signal sweeps continuously between a low frequency modulation and a high frequency modulation, the low frequency modulation being a frequency f1 in a range of 125kHz to 150kHz and the high frequency modulation being a frequency f2 in a range of 230kHz to 300kHz, where f2 - f1 is at least 0.4 * f1. A power amplifier changes an amplitude of the frequency modulated output signal during the low frequency modulations so that a current amplitude of the frequency modulated output signal is substantially constant, and a variable gain transformer adjusts a voltage of the frequency modulated output signal during starting of the lamp.