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:
Aug. 07, 2012

Filed:

Mar. 11, 2009
Applicant:

Tsung-hau Chang, Hsinchu, TW;

Inventor:

Tsung-Hau Chang, Hsinchu, TW;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H05B 39/02 (2006.01);
U.S. Cl.
CPC ...
Abstract

A light source apparatus and a light source driving circuit are provided. The light source driving circuit includes an operation amplifier (OP-AMP), a transistor, and a switch unit. A first input terminal and an output terminal of the OP-AMP couple to a predetermined voltage and a control terminal of the transistor, respectively. A first terminal of the transistor couples to a light source. The switch unit includes a first signal terminal receiving a first voltage greater than a predetermined voltage, a second signal terminal coupled to a second input terminal of the OP-AMP, a third signal terminal coupled to a second terminal of the transistor, and an enabling terminal receiving a driving voltage. A voltage of the third signal terminal or a voltage of the first signal terminal is determined to transmit to the second signal terminal in accordance with the driving voltage.


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