Design of Fuse-MOSFET Pair for Fault-Tolerant DC/DC Converters

This letter presents a method for selecting an appropriate rating of fuse and MOSFET in a fault-tolerant dc/dc converter to protect the circuit in a short-circuit operating condition. The proposed method is based on the Joule-integral principle to calculate the amount of energy associated with the fuse. Different fuse melting characteristics are used to select the appropriate melting time by comparing them with the thermal characteristics of the circuit. The tests performed demonstrate consistent behavior with simulation results and they show that the fuse current rating must be lower than the current rating of the switch in order to provide a safe and reliable operation of the converter.