| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp driving device which enables a discharge lamp to stably light without flicker even at an area of low-rate light control by supplying a current sufficient for discharge by impressing sufficient voltage to a primary winding 12 of a transformer 1 at the first cycle of start of lighting when switching from a turn-off period to a turn-on period. SOLUTION: The discharge lamp driving device comprises a discharge lamp 11 with an external electrode lighted by a high frequency rectangular wave current supplied to a secondary winding 13 side of the transformer 1, first and second capacitors 3, 4 for forming a middle point bias connected to the first winding 12 of the transformer in parallel, first and second switching elements 7, 8 for supplying current to the first winding of the transformer, and a control circuit 2 impressing driving signals to the respective switching elements. The value of the lamp current at the first cycle of start of lighting is made the same with the value after the second cycle by preliminarily charging the capacitor 4 by a preliminary charging circuit before the driving signal from the control circuit is impressed on the first winding of the transformer through the switching element. COPYRIGHT: (C)2004,JPO&NCIPI |
