| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting control device for vehicles capable of performing on/off switching with high accuracy. SOLUTION: The lighting control device has: an NMOS transistor 2 performing the on/off control of a drive current supplied to a semiconductor light source; and a control means controlling the NMOS transistor 2 according to a light adjustment control signal S2. The control means has: a triangular wave generating circuit 4 converting a voltage signal corresponding to the on/off state of the NMOS transistor 2 into a triangular wave voltage signal; and an operational amplifier unit including an operational amplifier 14 that compares the voltage value of the triangular wave voltage signal with a predetermined threshold on receiving the triangular wave voltage signal to move the triangular waveform voltage in the amplitude direction according to the comparison results maintaining the waveform of the triangular wave, and so controls the input value of the triangular wave generating circuit 4 as to constantly maintain the on-duty of the triangular wave for turning on the NMOS transistor 2. COPYRIGHT: (C)2009,JPO&INPIT |
