Patent ID: 9730291
Date: 2017-08-08
CPC Classifications: H05B

Claim:
1. A lighting device, comprising: a light source that emits an illumination light, the light source comprising a first group of light emitting diodes (LEDs) that emits a first light and a second group of LEDs that emits a second light, wherein the first light has a first Correlated Color Temperature (CCT) and wherein the second light causes the illumination light to have a warmer CCT; a differential amplifier to adjust a current flow through the second group of LEDs, wherein a reference signal having an adjustable voltage is provided to a first input of the differential amplifier and wherein the second light is switched on when a current provided to the light source is below a threshold corresponding to the adjustable reference voltage; and a current sensor to provide a sensor output signal to a second input of the differential amplifier, the sensor output signal having a second voltage corresponding to the current provided to the light source.