A SPICE based thermal model for the estimation of peak current capability of thyristor based devices

A thermal model of a thyristor, using an electrical analogue to heat flow in a layer, developed for use in the prediction of peak current capability of p-n-p-n devices, is presented. For any given current, a power waveform, representing the total power dissipated in the device for that current, is generated. This is then distributed over three heat sources representing the main locations of heat generation in an actual device. Comparisons with published data and experimental results yield close agreement with model predictions, indicating the validity of the approach. The model has also been used successfully in the development of thyristor based surge protectors