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:
Feb. 14, 2012
Filed:
Jan. 30, 2009
Bin Zhao, Irvine, CA (US);
Jack W. Cornish, Foothill Ranch, CA (US);
Brian B. Horng, Irvine, CA (US);
Victor K. Lee, Irvine, CA (US);
Andrew M. Kameya, Irvine, CA (US);
Bin Zhao, Irvine, CA (US);
Jack W. Cornish, Foothill Ranch, CA (US);
Brian B. Horng, Irvine, CA (US);
Victor K. Lee, Irvine, CA (US);
Andrew M. Kameya, Irvine, CA (US);
Freescale Semiconductor, Inc., Austin, TX (US);
Abstract
Techniques for dynamic headroom control in a light emitting diode (LED) system are disclosed. An output voltage is provided to drive a plurality of LED strings. A feedback controller monitors the tail voltages of the LED strings to identify the minimum tail voltage and adjusts the output voltage based on the lowest tail voltage. The LED strings grouped into subsets and the feedback controller is segmented such that, for a certain duration, a minimum tail voltage is determined for each subset. The minimum tail voltages of the subsets are used to determine the overall minimum tail voltage of the plurality of LED strings for the certain duration so as to control the output voltage in the following duration. The segments of the feedback controller can be implemented in separate integrated circuit (IC) packages, thereby facilitating adaptation to different numbers of LED strings by integrating the corresponding number of IC packages.