We present an electrical model for InGaN based high power light-emitting diodes (LEDs) with self-heating effect. The
model consists of an ideal diode connected with a series resistor. Because of the self-heating effect, the temperature of
the p-n junction (T<sub>j</sub>) is much higher than case temperature (T<sub>C</sub>), the maximum T<sub>j</sub> in our experiment is 148K high above case temperature. For the T<sub>j</sub> rises caused by self-heating effect, some temperature-dependent parameters, such as the band gap (E<sub>g</sub>) of InGaN which influence the reverse saturation current, the hole mobility (μ<sub>p</sub>) which influence the series resistance of p-type GaN, can be written as the function of forward current (I) and voltage (U). The voltage drops on p-n junction and equivalent series resistance are extracted from the measured I-V curve, and then the values of equivalent
series resistance at different forward power are obtained. By the self-heating effect, the values of equivalent series
resistance show a very strong forward power-dependent characteristics, the maximum equivalent series resistance in
this paper is about 1.6Ωat high forward power, nearly twice of the minimum one. It is worthwhile to point out that the
equivalent series resistance changed by self-heating effect and its influence on electronically property of GaN based
LEDs can not be neglected even at the low resistance level about 1Ωin our experiment.