logo

For the Inventor, By the Inventor

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.:

US 7528555 B1

PDFFull Text
Date of Patent:
May. 05, 2009

Filed:

Aug. 01, 2007

Led controller ic using only one pin to dim and set a maximum led current

Applicant:

Christian Gater, Dunblane, GB;

Inventor:

Christian Gater, Dunblane, GB;

Assignee:

Micrel, Inc., San Jose, CA (US);

Attorneys:

Patent Law Group LLP

Brian D. Ogonowsky

Primary Examiner:

Douglas W Owens

Assistant Examiner:

Jianzi Chen

Int. Cl.
CPC ...
G05F 1/00 (2006.01);
U.S. Cl.
CPC ...
Abstract

An LED driver IC is described that uses a single pin to both set the maximum current through one or more driven LEDs and variably control the brightness of the LEDs. A single resistor is connected to the control pin of the IC, where the value of the resistor sets the maximum current through the LEDs. A PWM source, outputting a pulse train at a particular duty cycle, is connected to the other end of the resistor, where the duty cycle controls the LED brightness level. When the PWM signal is low (e.g. ground), a sample and hold circuit connects the output of a feedback control voltage to an Imax current source to set a maximum current based on the external resistor value. An inverse of the duty cycle of the PWM controller controls a current Idim that is subtracted from the maximum current Imax set by the resistor. This difference current is used to control drivers for the LEDs.

Find Patent Forward Citations

Gater, Christian. (2009). Led controller ic using only one pin to dim and set a maximum led current (U.S. Patent No. 7528555). U.S. Patent and Trademark Office. https://idiyas.com/patent/badge/7528555

Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile

Loading…