| 摘要 |
PROBLEM TO BE SOLVED: To prevent flashing of a discharge lamp in the case where a battery voltage is low for preventing dazzling a car on the opposite lane. SOLUTION: As a battery voltage VB drops by operation of a stator motor of the like, a transistor 105 gets off. As a discharge lamp is lighted off by drop of the battery voltage VB, an output voltage V5 of a comparator circuit element 101 changes into a low level by rise of a lamp voltage VL in the negative direction, and a transistor 106 is switched off. Because of the transistors 105, 106 getting off, a transistor 108 gets on, an output voltage V4 changes into a high level, a transistor 109 is switched on, and action of a pulse width modulation circuit is stopped, thereby relighting of the discharge lamp is prohibited. |
