DISCHARGE LAMP LIGHTING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device in which an initial rising speed of a beam is increased in the case of a cold start. SOLUTION: A primary DC/DC converter circuit 11 controls an electric power supply to a high voltage discharge lamp La1 for a low beam by rising a direct current voltage of a direct current power source E. An auxiliary DC/DC converter circuit 4 is connected with the primary DC/DC converter circuit 11 in parallel, and its output end is connected with that of the primary DC/DC converter circuit 11 through a switching element Q4 and a diode D4 . In such a case that a voltage of a high voltage discharge lamp La1 is lower than a prescribed threshold value in an initial start period of the high voltage discharge lamp La1 just after a starting of the discharge lamp La1 , a control circuit 6 turns on the switching element Q4 and makes an electric power supply to the primary DC/DC converter circuit 11 as well as a primary inverter circuit 21 from the auxiliary DC/DC converter circuit 4, and an initial rising of a beam is speeded up in the high voltage discharge lamp La1 .