DISCHARGE LAMP LIGHTING DEVICE FOR DIMMING

摘要

PURPOSE:To perform continuous dimming even in low luminous flux area when the dimming quantity is continuously changed by a lighting circuit. CONSTITUTION:A current limiting element Z is variable in impedance, and controls the supplied power to a discharge lamp DL. The current limiting element Z controls the supplied power to the discharge lamp by changing the position of the intersection between the current-voltage characteristic of the output and the current-voltage characteristic of the discharge lamp DL. In the intersection, the differential coefficient of output voltage to passing current of the current limiting element Z is set smaller than the differential coefficient of lamp voltage to lamp current of the discharge lamp DL.