Influence of Electronic and Melting Fuses on the Transient Behavior of Automotive Power Supply Systems

In future automotive power supply systems, electronic fuses (eFuses) will be increasingly used for wire protection and controlling the power flow. However, the impact of eFuses on the overall power supply system is not well analyzed until now. Automated driving requires a stable power supply that should be robust against transient voltage and current pulses caused by, e.g., short-circuit faults and subsequent fuse tripping. To remain fail-operational, such pulses must not affect other redundant components. In this article, new behavioral simulation models for typical automotive melting and eFuses are presented that are optimized for the transient analysis of the fuse tripping event. The models are validated and parameterized by measurements. By simulating different supply topologies, the propagation of voltage and current pulses caused by a tripping event and their impact on the system stability are analyzed. Key findings are validated by measurements. On the one hand, it is shown that eFuses generate less critical overvoltages compared to melting fuses. On the other hand, the high current pulses caused by eFuse switching can trigger other eFuses in other remote branches to trip. With melting fuses, this behavior is not seen. Possible remedies for such a chain reaction are discussed.