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:
Aug. 02, 2011
Filed:
Mar. 20, 2007
Manoj Chandran, Chandler, AZ (US);
Alma Anderson, Chandler, AZ (US);
Manoj Chandran, Chandler, AZ (US);
Alma Anderson, Chandler, AZ (US);
NXP B.V., Eindhoven, NL;
Abstract
Methods and apparatus for implementing and operating pulse width modulation based LED dimmer controllers are described. A synchronization protocol is used to allow control information for the dimmer operations to be transferred to the PWM dimmer control clock domain from an external clock domain, such that visual artifacts are prevented when the control information is updated. Control information may be transferred to the LED dimmer controller via an I2C serial bus, and the synchronization protocol waits for an I2C STOP condition before updating control information across clock domain boundaries. The leading and trailing edges of an asserted group dimmer control signal are generated such that the active portion of the group dimmer control signal overlaps the active portion of individual LED pulse width modulated control signals. In this way, the pulse width modulation of the individual LED control signals is not cut off, or reduced in width by the group dimmer signal.