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. 03, 2015

Filed:

Oct. 14, 2010
Applicants:

Steven M. Barrow, Longmont, CO (US);

James H. Masson, Boulder, CO (US);

Irwin R. Nederbragt, Brighton, CO (US);

Inventors:

Steven M. Barrow, Longmont, CO (US);

James H. Masson, Boulder, CO (US);

Irwin R. Nederbragt, Brighton, CO (US);

Assignee:

Nationl Semiconductor Corporation, Santa Clara, CA (US);

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H05B 41/24 (2006.01); H05B 33/08 (2006.01);
U.S. Cl.
CPC ...
H05B 33/0815 (2013.01); H05B 33/0845 (2013.01); Y02B 20/346 (2013.01);
Abstract

A method includes receiving a sense signal having multiple pulses, where the sense signal is based on an output of a dimmer. The method also includes, for each of multiple sampling periods, (i) identifying a pulse duty cycle by sampling at least one pulse in the sense signal and calculating a duty cycle of the at least one pulse and (ii) generating an output value identifying a duty cycle for driving one or more LEDs. The output value is based on the pulse duty cycle. The method further includes generating a holding current for the dimmer (i) during the sampling of the at least one pulse in at least one of the sampling periods and (ii) when the pulse duty cycle is less than a specified threshold. The holding current can be applied continuously when the pulse duty cycle is less than the specified threshold (such as 15%).


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