| 摘要 |
PURPOSE:To prevent an instantaneous flashing of a discharge lamp when a power supply is turned on for a discharge lamp lighting device having a precedingly preheating timer circuit for start lighting the discharge lamp after preheating a filament for a predetermined period in turning on the power supply. CONSTITUTION:An action starting timing for a precedingly preheating timer circuit 4 is set to be earlier than an action starting timing for a drive circuit 3. When an om-signal of a predetermined time width is given to a switching transistor Q3 by the drive circuit 3, the precedingly preheating timer circuit 4 is already operating, and a normal lighting action is started only after a precedingly preheating action for a predetermined time. Instantaneous light emission of a discharge lamp La just after turning on a power supply can thus be eliminated, thereby deterioration of a life of filaments f1, f2 of the discharge lamp La can be prevented. |
