Electrothermal SPICE macromodeling of the power bipolar transistor including the avalanche and secondary breakdowns

Abstract

The analog behavioral SPICE macromodeling method has been used to develop a new BJT electrothermal macromodel, that includes the avalanche and secondary breakdowns. The electrical laws are modeled by means of "in-line equation" controlled sources, and the thermal laws are described with a dummy RC network. The great overcome of this behavioral macromodel is the portability to a large number of general purpose electronic circuits simulators. The starting point for the electrical model are the Gummel-Poon equations, that were adapted for power bipolar structures. Thus the electrothermal macromodel keeps the compatibility with existing purely electric models. Several methods to enhance the analysis convergence have been proposed and the simulation results show a good agreement with data sheets characteristics.