Modelling mutual thermal interactions between power LEDs in SPICE

• The new dc electrothermal model of power LEDs is proposed.
• This model takes into account mutual thermal coupling between LEDs situated on the common base.
• The form of the model and the method of its parameters estimation is described.
• The correctness of the model is proved by comparing the results of calculations and measurements.

The paper concerns modelling an influence of self-heating and mutual thermal coupling on power LEDs characteristics. The electrothermal model of a power LED for SPICE software taking into account electric, thermal and optical properties of the considered devices, and particularly mutual thermal coupling between the devices situated on the common heat-sink, is presented. The method of estimating model parameters values is proposed and the method of measuring their own and mutual thermal resistance between power LEDs is described. Using the elaborated model the characteristics of selected diodes are calculated at different cooling conditions of the investigated LED. The obtained results of calculations are compared with the measurements results for a single diode, two diodes situated on the common heat-sink and a LED module.