| 摘要 |
PROBLEM TO BE SOLVED: To enable to impress a high voltage pulse efficiently on a discharge lamp from an ignitor at starting of lighting, and to supply power efficiently to the discharge lamp at normal lighting. SOLUTION: An AC voltage Va1 is generated from a primary side coil n1 of a transformer TR to constitute a first DC/DC conversion circuit 13 which outputs respectively an output converted into a desired DC and AC voltage from the voltage of a DC power supply 11, and this AC voltage is converted into a DC voltage Vd3 of a constant voltage circuit 18. This DC voltage is supplied as a power source for a control circuit 20 for generating the AC voltage Va1 and for a DC/AC conversion drive circuit 19 for driving a DC/AC conversion circuit 17 to light the discharge lamp 16. A filter circuit 21 for high frequency cut constituted of inductors L1, L2 and a capacitor C1 is connected between the output of the DC/AC conversion circuit 17 and an ignitor 15, and after the discharge lamp 16 is lighted, the capacitor C1 is disconnected. COPYRIGHT: (C)2008,JPO&INPIT |
