| 摘要 |
PROBLEM TO BE SOLVED: To prevent deterioration of the startability of an electrodeless discharge lamp in intermittent operation. SOLUTION: A driving frequency correction circuit 15 is provided which corrects the frequency of driving signals V<SB>DH</SB>, V<SB>DL</SB>under the control of an intermittent oscillator circuit 13 during the on-period Ton where a driving circuit 11 outputs the driving signals V<SB>DH</SB>, V<SB>DL</SB>so that an output voltage Vx of a power conversion circuit 9 becomes generally constant. The larger the rate of decrease of a direct current output voltage Vdc is, the more largely the operating frequency (the driving frequency) finv decreases so that a high frequency output of the power conversion circuit 9 increases. This becomes it possible that an applied voltage (an output voltage of the power conversion circuit 9) of an induction coil 5 is kept generally constant in the on-period Ton of intermittent oscillation operation, and thus the deterioration of startability in a dark place in an initial start-up or the like can be prevented. COPYRIGHT: (C)2006,JPO&NCIPI |
