DISCHARGE LAMP LIGHTING DEVICE

摘要

In a discharge lamp lighting device, a control circuit for turning first and second switching elements of a polarity inverting circuit alternately ON/OFF at a high frequency to alternately generate a longer ON period and a shorter ON period of the second switching element than those of the first switching element to apply a rectangular low frequency voltage to a discharge lamp, superimposes a DC component of the polarity inverting circuit upon a resonance pulse signals from a load resonance circuit to continuously change a switching frequency of the switching elements for the predetermined time from the start time point of one of the longer and shorter ON periods, and supplied to the lamp a first energy necessary for starting and lighting the lamp with a high pulse voltage obtained through LC resonance and for smoothly shifting the lamp to an arc discharge state.