Abstract: A lamp driving circuit of a vehicle turn/hazard system blinks a turn hazard lamp 10 by passing a current through a relay contact C of a relay RY intermittently. The relay contact of the relay RY is turned on earlier than a semiconductor switch 20 which is provided between a relay and a battery is, and the former is turned off later than the latter is. During the period while both the relay contact and semiconductor switch are ON, the turn/hazard lamp is illuminated. A first and a second pulse signal are generated to turn on/off the relay contact C and semiconductor device, respectively. The relationship therebetween is changed at regular or random intervals. In this configuration, the lamp driving circuit for a turn hazard system can minimize exhaustion of the relay contact and improve the endurance thereof.

Abstract: A flicker synchronizing signal generating section (23) generates a flicker synchronizing signal having a drive start-on time for front and rear hazard lamps (6a, 6b, 7a, 7b) set shorter than a drive start-off time in each period in accordance with a hazard signal and using the drive start-on time as a trigger period, a respective hazard output signal generating section (34, 44) generates a hazard output signal for having a drive of the hazard lamps start within the trigger period in accordance with the flicker synchronizing signal, with a drive-on time and a drive-off time set equal in each period thereof and with an interval from a start of the drive within each current trigger period to a start of the drive within the next trigger period set equal to the period of the flicker synchronizing signal, and a respective lamp driving section (33, 43) drives to flicker an associated hazard lamp in accordance with the hazard output signal.