| 摘要 |
PROBLEM TO BE SOLVED: To detect a ground fault of a plurality of detection object portions out of the portions connected to each electrode of a plurality of semiconductor light sources. SOLUTION: A resistor R1 is connected to both ends of LEDs 1, 2 which are the detection objects of the LED 1-LED 5 arranged between output terminals 30, 32 of a DC/DC converter 12, and making the both ends of the resistor R1 as detection object portions to be connected to an anode of the LED 1 and a cathode of the LED 2, one end of the resistor R1 is connected to a ground fault circuit 16 through a connection point 38. When the detection object portion which is connected to the both ends of the resistor R1 and connected to the output terminal 30 or the connecting point 38 has the ground fault, the voltage V1 of the connecting point 38 decreases to a ground potential, thereby by detecting this voltage change by the ground fault detection circuit 16, the ground fault of the detection object portion connected to the output terminal 30 or the connecting point 38 can be detected. COPYRIGHT: (C)2009,JPO&INPIT |
