The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 14, 2020
Filed:
Aug. 30, 2018
Koito Manufacturing Co., Ltd., Tokyo, JP;
Tomoyuki Ichikawa, Shizuoka, JP;
Satoshi Kikuchi, Shizuoka, JP;
KOITO MANUFACTURING CO., LTD., Minato-Ku, Tokyo, JP;
Abstract
A current detection circuit generates a current detection signal Vthat corresponds to a lamp current Isupplied from a switching converter to a semiconductor light source. A hysteresis comparator compares a current detection signal Vwith an upper-side threshold signal Vand a lower-side threshold signal Vdetermined according to an analog dimming signal, and generates a control pulse Sthat corresponds to the comparison result. A driver drives a switching transistor according to the control pulse. A PWM dimming circuit generates a gradual change signal by dulling a PWM (pulse width modulation) dimming signal, and changes the analog dimming signal based on the gradual change signal.