| 摘要 |
PROBLEM TO BE SOLVED: To provide a feedback control device of discharge lamp current by which the discharge lamp current is kept constant and jumping, fadeout and flickering of lighting output are prevented, and further to obtain a simplified circuit of the detecting part of discharge lamp enabling to manufacture at low cost. SOLUTION: A detecting resistor 15 is provided in series with a discharge lamp 11, and a series circuit of a reference capacitor 16 corresponding to a resonance capacitor 10 and a reference resistor 17 corresponding to the detecting resistor is provided in parallel with the series circuit of the above discharge lamp 11 and the detecting resistor 15. By the relations of the voltage V1 of both ends of the above detecting resistor 15 and the voltage V2 at both ends of the above reference resistor 17, a control mans to feedback control the above inverter circuit 2 is provide to keep constant the discharge lamp current 11a. |
