Patent ID: 8928249
Filing Date: 2015-01-06
Classification: H05B

Abstract:
1. A tunable lighting system comprising: a white light emitting semiconductor device and a first non-white color light emitting semiconductor device; a first driver for applying a first controllable drive current to the white light emitting semiconductor device and a separately controllable portion of the first drive current to the first non-white color light emitting semiconductor device; a second non-white color light emitting semiconductor device, the second non-white color different from the first non-white color; a second driver for applying a second controllable drive current to the second non-white color light emitting semiconductor device; an input for receiving user selections of values related to a spectral characteristic of white combined light output of the tunable lighting system; and a controller connected to control the first driver and the second driver; wherein the controller is configured to: control the first driver to maintain application of full drive current to the white light emitting semiconductor device responsive to all of the received input values related to the spectral characteristic; and in response to the user selecting a range of values related to the spectral characteristic of the white light output, selectively operate the drivers to: adjust the controllable drive current provided to the first non-white color light emitting semiconductor device and adjust the controllable drive current provided to the second non-white color light emitting semiconductor device, in a manner causing combined light output from the white and non-white light emitting semiconductor devices to exhibit the selected values for the spectral characteristic, while maintaining substantially constant overall output intensity for the combined light output over the selected values.