The Foster type electro-thermal RC network inside power semiconductor device is normally provided by manufacturers for junction temperature estimation. However it will result in inaccuracy or error when further attaching the Foster network with thermal impedances of heat sink or thermal grease, which are essential components outside power semiconductor devices and will determine the device case temperature level. In order to overcome this unsolved problem, a new thermal model is proposed and verified by simulation in this paper. It is concluded that by the proposed thermal model, it is possible to extend the Foster thermal network inside power semiconductor device, achieving relative more accurate estimation of both junction and case temperature.
Proceedings of Pcim Europe 2013, 2013, p. 1042-1046