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:
Dec. 01, 2015
Filed:
Nov. 06, 2013
Nxp B.v., Eindhoven, NL;
Hendrik Boezen, Nijmegen, NL;
NXP B.V., Eindhoven, NL;
Abstract
An LED control circuit for controlling a current supplied to an LED unit is disclosed. A sense resistor is included for sensing an output current provided from an output node. A comparator circuit is provided for detecting upper and lower thresholds in the output current based on the voltages at ends of the sense resistor, and for controlling a current supply to maintain the current between the thresholds. The comparator circuit comprises a reference current source and reference resistors, for generating upper and lower threshold references. The comparator circuit further comprises a comparator for detecting a mid-range voltage dependent on the output current and deriving a control signal which indicates if the detected voltage is above or below the mid-range voltage. The control signal is used to adjust the reference current source, thereby to vary the upper and lower threshold references to maintain a constant median or average output current.