| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an overvoltage protection circuit for a vehicle lighting fixture capable of protecting a light source from overvoltage while keeping a lighting state of the light source even if overvoltage is supplied, without increasing cost. <P>SOLUTION: The overvoltage protection circuit 10 for the vehicle lighting fixture is provided between the light source 12 used for the vehicle lighting fixture and an electric power supplying source 14 supplying power to the light source 12, and protects the light source 12 by suppressing voltage applied on the light source 12 when the supplied voltage from the electric power supplying source 14 is overvoltage exceeding permissible voltage. The overvoltage protection circuit for the vehicle lighting fixture comprises an overvoltage detecting means 20 detecting that the voltage applied to the light source 12 becomes overvoltage, a bypass means 30 partially branching a flow of the electric current supplied to the light source 12 when the overvoltage is detected by the overvoltage detecting means 20, and a voltage dropping means 40 dropping supplied voltage from the electric power supplying source 14 on the electric power supplying source 14 side more than the bypass means 30. <P>COPYRIGHT: (C)2007,JPO&INPIT |
