Modeling and Simulation Research on Conducted Immunity of Function Module of the Digital Control Circuit Based on RFI

The research status of the digital control circuit chip level and system level electromagnetic immunity is analyzed in this article firstly. Secondly, a set of device for the digital control circuit based on advanced reduced instruciton set computer (RISC) machine is developed. The impedance of the components on the coupling path of the modules is extracted and the equivalent circuit is established. Based on the integrated circuits immunity model-conducted immunity (ICIM-CI), the behavior level modeling and simulation of the power module and input/output (IO) module are carried out using the IC-EMC software. The direct power injection method based on radio frequency interference (RFI) is used to test the interference immunity of the modules, and the failure mode and sensitivity threshold of the digital control circuit is obtained. The RFI based immunity modeling and simulation models for the power module and IO module are validated through simulation and testing comparison using the “board level-chip level” modeling and simulation method. The immunity of the power module is not only related to the low-dropout regulator power chip, but also to the peripheral circuit of the power module. The simulation research of IO module immunity considers the actual working mode of IO chip pins and calculates the IO pin response under actual working conditions. The method has a certain value to study the coupling mechanism of the conducted interference.