A lighting device includes a light source that emits an illumination light. The light source includes a first group of light emitting diodes (LEDs) to emit a first light, a second group of LEDs to emit a second light, and a third group of LEDs to emit a third light. The second light is warmer light than the first light, and the third light is cooler light than the first light. The lighting device further includes a first difference amplifier that controls a first current flow through the second group of LEDs at least based on a magnitude of a current flowing through the light source. The lighting device also includes a second difference amplifier that controls a second current flow through the third group of LEDs at least based on the magnitude of the current flowing through the light source.