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.

Date of Patent:
Sep. 24, 2019

Filed:

Aug. 16, 2017
Applicant:

Koito Manufacturing Co., Ltd., Tokyo, JP;

Inventors:

Shohei Yanagizu, Shizuoka, JP;

Masayasu Ito, Shizuoka, JP;

Takao Muramatsu, Shizuoka, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H05B 33/08 (2006.01); B60Q 1/04 (2006.01); B60Q 11/00 (2006.01);
U.S. Cl.
CPC ...
H05B 33/0884 (2013.01); B60Q 1/04 (2013.01); H05B 33/0809 (2013.01); H05B 33/0821 (2013.01); H05B 33/0887 (2013.01); B60Q 11/00 (2013.01); H05B 33/083 (2013.01);
Abstract

There is provided a lighting circuit configured to drive a light emitting unit including a first light source and a second light source connected in series. The lighting circuit includes a first pin connected to one end of the first light source, a second pin connected to a connection node of the first light source and the second light source, a third pin connected to one end of the second light source, a drive circuit configured to supply a drive current to the light emitting unit, a bypass switch provided between the second pin and the third pin, a first resistor provided in parallel with the bypass switch between the second pin and the third pin, and an abnormality detection circuit configured to detect abnormality based on a detection voltage generated between the second pin and the third pin when an ON signal is applied to the bypass switch.


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