SHORT CIRCUIT DETECTING DEVICE OF HEADLAMP LOAD LINE

摘要

PROBLEM TO BE SOLVED: To perform ON-OFF control of a driving element without erroneously detecting a load short circuit even if battery source voltage reduces. SOLUTION: This short circuit detecting device has a driving element output circuit part 6 for detecting a short circuit of a load line when voltage of a connecting point of the driving element 2 and a headlamp 1 reduces more than preset short circuit detecting voltage by a CPU 4 and stopping supply of a power source from a battery to the headlamp 1 by turning off the driving element 2 by controlling a driving circuit 3, and when the battery source voltage VB is higher than a preset battery voltage value, a driving signal is outputted for performing short circuit detection control of the driving element output circuit part 6, and when the battery source voltage VB is lower than the preset battery voltage value, a control stopping signal is outputted for stopping the short circuit detection control of the driving element output circuit part 6 to control driving of the driving element output circuit part 6.