| 摘要 |
PROBLEM TO BE SOLVED: To assure adequate driving condition to prevent, for example, the instantaneous lighting phenomenon when the power switch is turned on and also protect the apparatus from the over-voltage condition when the lamp is not let. SOLUTION: Operation of the switching circuit 6 is controlled by a driving condition control means 14 so that only the first switching device 4 side for charging among the first and second switching devices 4, 5 is operated until the level of the voltage Vc an electrolytic capacitor CA detected by a detecting means 13 reaches a predetermined level Va . Thereby, the switching circuit 6 is never operated to immediately execute the on-off oscillating operation and only the charging operation of the electrolytic capacitor CA is executed when the power switch is turned on where the electrolytic capacitor CA does not have any charges. Accordingly, high voltage is not generated in an output circuit N22 and the instantaneous lighting phenomenon of the discharge lamp 7 caused by a high voltage at the winding N22 when the power is turned on can be prevented. |
