| 摘要 |
PROBLEM TO BE SOLVED: To provide a driving circuit for vehicle lamp capable of preventing temperature rise of a light-emitting element of a vehicle lamp at the time of decrease of a vehicle speed with a simple structure. SOLUTION: The driving circuit for vehicle lamp 10 is constituted by including a constant current circuit 11. A reference voltage which is generated on a cathode side of a Zenor diode 32 connected through a battery voltage input terminal 14 and a resistor 34 is inputted to a non-reverse input terminal of a differential amplifier 26 constituting the constant current circuit 11. However, since a resistor 30 is connected in parallel with the Zenor diode 32, when the battery voltage drops due to the ambient temperature rise or the like accompanying the decrease of vehicle speed, the reference voltage also drops accompanied with that. As the reference voltage drops, the current outputted from the constant current circuit 11 to an LED 20 also drops. COPYRIGHT: (C)2008,JPO&INPIT |
