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.
Patent No.:
Date of Patent:
Nov. 01, 2011
Filed:
Apr. 18, 2008
Applicants:
Chin-lung Wu, Tainan County, TW;
Chun-kai Wang, Tainan County, TW;
Kai-ji Chen, Tainan County, TW;
Inventors:
Assignee:
Himax Analogic, Inc., Hsinchu, TW;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G09G 3/32 (2006.01);
U.S. Cl.
CPC ...
Abstract
A circuit and a method for driving light emitting diodes (LEDs) are provided. First, an input voltage is converted into an output voltage and the output voltage is transmitted to the anode terminals of LED strings. The output voltage is reduced when the output voltage is greater than a first threshold voltage and the output voltage is reduced when the lowest level among the cathode terminal voltages of all the LED strings is greater than a second threshold voltage. Thus, the output voltage can be maintained at a lower level for driving all the LED strings to reduce unnecessary power wastage.