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:

Nov. 28, 2017
Applicant:

Rohm Co., Ltd., Kyoto, JP;

Inventors:

Yoshiyuki Nakatani, Kyoto, JP;

Shinsuke Takagimoto, Kyoto, JP;

Assignee:

Rohm Co., Ltd., Kyoto, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H05B 33/08 (2006.01);
U.S. Cl.
CPC ...
H05B 33/089 (2013.01); H05B 33/083 (2013.01);
Abstract

A ground fault detection circuit includes an input portion, and a ground fault determination unit. The input portion inputs an anode voltage of a series connection unit constituted of a plurality of light emission elements. When an anode voltage of the series connection unit input by the input portion is lower than or equal to a predetermined value less than a product of an on-resistance of the short-circuit switch disposed in parallel to each of the light emission elements and current supplied to the series connection unit, the ground fault determination unit determines that a ground fault has occurred without the short-circuit switch in a ground fault path.


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