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:
May. 25, 2010
Filed:
May. 14, 2007
Applicants:
Alexander Mednik, Campbell, CA (US);
Rohit Tirumala, Sunnyvale, CA (US);
Inventors:
Alexander Mednik, Campbell, CA (US);
Rohit Tirumala, Sunnyvale, CA (US);
Assignee:
Supertex, Inc., Sunnyvale, CA (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H05B 37/02 (2006.01);
U.S. Cl.
CPC ...
Abstract
A dimming circuit for driving a string of LEDs at constant current has a power converter. A control circuit is coupled to the power converter. A plurality of shunt switches is provided. An individual shut switch is coupled to each LED. Each LED can be shunted individually by the individual shunt switch. The control circuit corrects an internal DC state based on a feedback signal Vso that the output current of the power converter remains unchanged when at least one LED is shunted.