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Systems and methods for controlling solid state lighting devices and lighting apparatus incorporating such systems and/or methods

  • US 10,178,723 B2
  • Filed: 06/03/2011
  • Issued: 01/08/2019
  • Est. Priority Date: 06/03/2011
  • Status: Active Grant
First Claim
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1. A lighting apparatus comprising:

  • a string of serially-connected light-emitting diodes (LEDs) coupled between first and second terminals and comprising a first set of LEDs providing first light output having a first chromaticity and a second set of LEDs providing second light output having a second chromaticity different from the first chromaticity; and

    a control circuit comprising a bypass circuit, coupled to the string, that bypasses at least one LED of at least one of the first and second sets of LEDs and varies a color temperature produced by the string by differentially varying respective currents passing through the first and second sets of LEDs of the string responsive to a variation in a total current passing between the first and second terminals,wherein the bypass circuit comprises a variable resistance circuit configured to continuously and differentially vary the respective currents passing through the first and second sets of LEDs, andwherein the control circuit is configured to provide the color temperature as a fixed color temperature over a first range of brightness levels and to conform the color temperature to the Planckian locus over a second range of brightness levels that is lower than the first range of brightness levels.

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