Adjusting Color Temperature in a Dimmable LED Lighting System
AssigneeiWatt Inc.
InventorsLiang Yan, Junjie Zheng
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Abstract
A LED lighting system, such as a dimmable LED lamp, that may simulate the performance of an incandescent bulb. LED strings of different colors may be connected to the output of a single LED driver that regulates an overall intensity of light produced by the LED lighting system. The color of the LED lighting system may be controlled by circuitry, such as one or more switches, that allocates current between the LED strings to change the color temperature of light emitted by the LED lighting system as the light intensity changes.
Claims27
A light emitting diode (LED) lighting system, comprising:
- a LED driver configured to generate a regulated current at an output of the LED driver;
- a first LED string coupled to the output of the LED driver and configured to emit light of a first color temperature based on a first portion of the regulated current flowing through the first LED string;
- a second LED string coupled to the output of the LED driver and configured to emit light of a second color temperature based on a second portion of the regulated current flowing through the second LED string, the second color temperature being different than the first color temperature;
- and
- circuitry configured to control allocation of the regulated current between the first portion of the regulated current flowing through the first LED string and the second portion of the regulated current flowing through the second LED string responsive to a signal indicative of a desired brightness level.
A method of operation in a light emitting diode (LED) lighting system, the method comprising:
- receiving a signal indicative of a desired brightness level;
- generating a regulated current at an output of a LED driver, wherein a first LED string is configured to emit light of a first color temperature based on a first portion of the regulated current flowing through the first LED string and the second LED string is configured to emit a light of a second color temperature based on a second portion of the regulated current flowing through the second LED string, the second color temperature being different than the first color temperature;
- and
- controlling an allocation of the regulated current between the first portion of the regulated current flowing through the first LED string and the second portion of the regulated current flowing through the second LED string responsive to the signal indicative of the desired brightness level.
Dependencies are inferred from the claim text.