Current-voltage model of LED light sources

Amplitude modulation is rarely used for dimming light-emitting diodes in polychromatic luminaires due to big color shifts caused by varying magnitude of LED driving current and nonlinear relationship between intensity of a diode and driving current. Current-voltage empirical model of light-emitting diode devices, presented in this paper, creates a way to estimate diode´s colorimetric properties based on driving current and diode´s voltage. The accuracy of the model was tested under direct and pulsed driving current. For DC current, the color difference between the modeled color point of the diode and the actual measured one, is much lower than the just noticeable color difference (mean ΔE_ab* 0.15). The model can be used e.g. as a color feedback mechanism in high power trichromatic luminaires such as profile lamps.