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:
Feb. 14, 2017

Filed:

Sep. 11, 2013
Applicant:

Fujitsu Limited, Kawasaki-shi, Kanagawa, JP;

Inventors:

Mariko Kase, Isehara, JP;

Satoshi Ide, Yokohama, JP;

Assignee:

FUJITSU LIMITED, Kawasaki, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01S 5/026 (2006.01); H02J 4/00 (2006.01); H05B 33/08 (2006.01);
U.S. Cl.
CPC ...
H02J 4/00 (2013.01); H05B 33/0812 (2013.01); Y02B 20/345 (2013.01); Y10T 307/406 (2015.04);
Abstract

A drive circuit that drives a light emitting element coupled to a first output terminal of a differential circuit, the drive circuit includes: a dummy load provided at a second output terminal of the differential circuit, a resistor coupled between the first output terminal and the second output terminal, two transistors coupled to a voltage source and applying a current to the light emitting element and the dummy load, and a comparative amplifying circuit having a non-inverting input terminal coupled to a reference voltage, an inverting input terminal coupled to at least the first output terminal of the differential circuit via a resistor, and an output terminal coupled to gates of the two transistors.


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