×

ADJUSTING COLOR TEMPERATURE IN A DIMMABLE LED LIGHTING SYSTEM

  • US 20180103523A1
  • Filed: 12/11/2017
  • Published: 04/12/2018
  • Est. Priority Date: 01/25/2013
  • Status: Active Grant
First Claim
Patent Images

1. A light emitting diode (LED) controller for a switching power converter, comprising:

  • a dimming detection module configured to receive a rectified input voltage, to detect a desired brightness level from the magnitude and/or shape of the rectified input voltage, and to thereby generate a target current level signal that varies responsive to a variation of the desired brightness level;

    a regulator configured to regulate a cycling of a power switch to generate a regulated current at an output of the switching power converter responsive to the target current level signal; and

    circuitry configured to allocate the regulated current between a first portion of the regulated current flowing through a first LED string and the second portion of the regulated current flowing through a second LED string responsive to changes in the desired brightness level such that a light output from the first LED string and the second LED string increases in redness responsive to a decrease in the desired brightness level, the circuitry comprising;

    a first switch coupled in series with the first LED string, wherein a duty cycle of ON and OFF times of the first switch is responsive to a first switch control signal; and

    a color control module configured to generate the first switch control signal responsive to the target current level.

View all claims
  • 3 Assignments
Timeline View
Assignment View
    ×
    ×