| 摘要 |
PURPOSE:To shorten the half-wave lighting period and accelerate the transition to the ordinary lighting by controlling the DC power output of a DC power source only in the unlighted period of the half-wave lighting period of a discharge lamp higher than that at the time of ordinary lighting. CONSTITUTION:A half-wave lighting detecting means detecting the half-wave lighting of a discharge lamp 17 and a power control means controlling the DC power voltage V0 of a DC power source only in the unlighted period of the half-wave lighting period higher than that at the time of ordinary lighting are provided. The half-wave lighting detecting means and the power control means are formed with a converter 26a, a reference power source 26b, a timer circuit 26e constituted of a general purpose timer IC, and a circuit constituted of an AND gate 26g, transistor 26i, capacitors 26d and 26f, and resistors 26c, 26h and 26j. The half-wave lighting period is shortened, the transition to the ordinary lighting can be accelerated, the power loss can be reduced. |
