Search International and National Patent Collections

1. (WO2017150322) VEHICLE LAMP FIXTURE AND LIGHTING CIRCUIT FOR SAME

Pub. No.:    WO/2017/150322    International Application No.:    PCT/JP2017/006743
Publication Date: Sat Sep 09 01:59:59 CEST 2017 International Filing Date: Fri Feb 24 00:59:59 CET 2017
IPC: H05B 37/02
B60Q 1/00
B60Q 1/14
H01L 33/00
H02M 3/155
Applicants: KOITO MANUFACTURING CO.,LTD.
株式会社小糸製作所
Inventors: ICHIKAWA, Tomoyuki
市川 知幸
KIKUCHI, Satoshi
菊池 賢
Title: VEHICLE LAMP FIXTURE AND LIGHTING CIRCUIT FOR SAME
Abstract:
In the present invention, a current detection circuit (34) generates a current detection signal VCS which is commensurate to a lamp current ILAMP supplied from a switching converter (30) to a semiconductor light source (10). A hysteresis comparator (36) compares the current detection signal VCS to an upper threshold value signal VTHH and a lower threshold value signal VTHL which are determined in accordance with an analog light-modulation signal VADIM, and generates a control pulse SCNT in accordance with the result of the comparison. A driver (38) drives a switching transistor M1 in accordance with the control pulse SCNT. A PWM light-modulation circuit (90) smoothes out a pulse width modulation (PWM) light-modulation signal SPWM and generates a gradually-varying signal, then varies the analog light modulation signal VADIM on the basis of the gradually-varying signal.