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:
Jan. 05, 2016

Filed:

May. 09, 2012
Applicants:

Shu-min Lin, Taichung, TW;

Jyi-si Lo, Taoyuan County, TW;

Ying-hsi Lin, Hsin-Chu, TW;

Inventors:

Shu-Min Lin, Taichung, TW;

Jyi-Si Lo, Taoyuan County, TW;

Ying-Hsi Lin, Hsin-Chu, TW;

Assignee:

Realtek Semiconductor Corp., Science Park, HsinChu, TW;

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H05B 37/02 (2006.01); H05B 33/08 (2006.01);
U.S. Cl.
CPC ...
H05B 33/0851 (2013.01);
Abstract

An operating circuit applied to a backlight includes at least one current control circuit, where the current control circuit includes a transistor, an operational amplifier and a switch module. The transistor has a gate, a first electrode and a second electrode, where the first electrode is coupled to a lighting element, and the second electrode is coupled to a resistor. The operational amplifier has positive and negative input terminals, and positive and negative output terminals. The switch module switches a connection relationship between the positive input terminal, the negative input terminal, the reference voltage and the second electrode of the transistor, and switches a connection relationship between the positive output terminal, the negative output terminal and the gate of the transistor to make the close loop form a negative feedback, and the current of the lighting element not influenced by an offset voltage of the operational amplifier.


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