Simulation of thermal effects in electrical systems

Simulators based on the SPI CE program have one major limitation in that every device in a system must operate at the same temperature. A discussion is presented of modifications implemented in SPICE such that each device´s operating temperature can be set independently by operating-point power dissipation and/or user input, and can vary during a transient analysis controlled by a user-defined parallel thermal network. The method used to describe the thermal system is an electrical analog. The temperature is characterized as voltage and the power as current. The thermal resistances and capacitances are represented with resistors and capacitors. The thermal network is then solved simultaneously with the electrical network using the same algorithms