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:
Nov. 18, 2014
Filed:
Feb. 06, 2013
Analog Devices, Inc., Norwood, MA (US);
Jonathan Kraft, Frederick, CO (US);
Analog Devices, Inc., Norwood, MA (US);
Abstract
A line voltage control circuit for use with a multi-string LED drive system which provides a common line voltage for multiple LED strings that are connected to respective current sink circuits at respective junctions. An error amplifier receives the minimum junction voltage and a reference 'desired junction voltage' at respective inputs, and a voltage regulator outputs the line voltage in response to a voltage applied to a feedback input. A comparator toggles an output when the maximum junction voltage (V) exceeds a reference limit (V). A multiplexer receives the error amplifier output and a fixed voltage at respective inputs and provides one of the signals to the regulator's feedback input in response to the comparator output. When V>V, the fixed voltage is provided to the feedback input and the line voltage is reduced, thereby protecting low voltage current sinks from potentially damaging high voltages.