| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device in which a current of the discharge lamp is increased while avoiding a lamp-specific acoustic resonant frequency, and warm up of the discharge lamp is carried out during a fixed time after sweeping a switching frequency in an AC voltage application at start-up time of the discharge lamp.SOLUTION: At start-up time of the discharge lamp, as for the switching frequency of the AC voltage applied to an LC series circuit of an inductor L23, and a capacitor C24 is swept in the vicinity of a frequency having a value which is obtained by dividing the resonant frequency of the LC series circuit by an odd number. After sweeping, the switching frequency is brought to around a swept frequency or to one higher than that, and an on/off duty ratio of switching elements Q22 to Q25 of the DC-AC inverter circuit 23 is controlled. After operation at the start-up of this discharge lamp, the switching frequency is brought to a lower frequency than around the swept frequency, and the discharge lamp is turned on. |
