Robust Vertical Interface Design for Battery Management Systems: EMI Failure Analysis and Countermeasures

The rapid electrification of the automotive industry has made the electromagnetic compatibility (EMC) of battery management systems (BMS) a crucial factor in ensuring vehicle safety and reliability. In this paper, the susceptibility of a vertical interface (VIF) to electromagnetic interference (EMI) for digital data transfer between galvanically isolated IC modules is addressed at the IC level. The study begins with a system-level preliminary experimental susceptibility assessment using direct power injection (DPI) tests in compliance with ISO 11452-7. Leveraging transistor-level simulations and fundamental circuit analysis, the primary failure mechanisms and their root causes are identified and mitigated through targeted IC-level countermeasures. The efficacy of these countermeasures is verified via accurate transistor-level simulations and experimental measurements on a test chip fabricated in 110 nm BCD technology. A dual-transceiver peer-to-peer communication setup is employed to rigorously assess the robustness of the bidirectional link under EMI excitation. Experimental results demonstrate a robustness enhancement exceeding 15 dB within the critical 1–10 MHz frequency range, significantly improving the interface’s most vulnerable band. This enhancement ensures full compliance with the stringent requirements of automotive BMS applications.