| 摘要 |
PURPOSE:To shorten the light flux stabilizing time, prevent the breakage of a slowly leaked HID lamp, and prevent a device from becoming large-sized and heavyweight. CONSTITUTION:The switching of FETQ1 of a booster chopper circuit 1 is controlled by a control circuit 3. A timer 7 counting the time required for the lamp voltage VLa to reach nearly the rated lamp voltage at least immediately after the start of an HID lamp La is provided on the control circuit 3. A current larger than the rated lamp current is fed to the HID lamp La during the limit time of the timer 7. The excess current larger than the rated value is fed to the HID lamp La to shorten the light flux stabilizing time. After the limit time of the timer 7 is completed, the output state of the booster chopper circuit 1 is limited to the state to feed the lamp current capable of maintaining the rated lighting state of the HID lamp La. No excess current flows in the HID lamp La after the limit time of the timer 7 is completed. |
