Electrothermal methodology applied to flicker analysis in off-line LED systems

In this paper a study about LED (light-emitting diode) luminous flux performance using an electrothermal methodology is presented. The objective is to evaluate and quantify the flicker given out by LEDs supplied by constant current with superposed sinusoidal ripples, which is commonly found in off-line LED drivers. Mathematical analysis and theoretical predictions are made taking into account the photometrical, electrical and thermal characteristics of the LED module. Three laboratory prototypes with different heatsinks were tested to verify the validity of the proposed analysis. Experimental results are presented to evaluate the LED photometrical behavior under current ripple.