Software-Based Thermal Protection of a Vehicular Electronic Fuse's Semiconductor Device

A fail-operational vehicular power system is a prerequisite for autonomous driving functions. Thus, novel vehicular power systems include electronic fuses (eFuses) instead of melting fuses to implement advanced protection mechanisms. In order to perform their functions over the whole lifetime reliably, the semiconductor devices of eFuses must be protected from damage due to a thermal overload. In this paper, a software-based approach is proposed to determine the junction temperature of a transistor using an electrothermal model of the device. Different modeling approaches (Foster, Cauer) are explained and compared regarding technical feasibility. Measurements exhibit that the discretized algorithm for monitoring the temperature of the eFuse is viable when realistic values for the ambient temperature within the power distribution unit are processed.