Automotive EMC Analysis of Touch Sensing IC 2024-26-0353

The technology in the automotive industry is evolving rapidly in recent times. Thus, with the development of new technologies, the challenges are also ever-increasing from an Electromagnetic Interference and Susceptibility (EMI/EMC) perspective. A lot of the latest technologies in Adaptive Driver Assistance Systems (ADAS), which include Rear Drive Assist, Blind Spot Detection (BSD), Lane Change Assist (LCA) to name a few, and other features like Anti-Braking System (ABS), Emergency Brake Assist (EBD) etc. rely heavily on different types of sensors and their detection circuitry. In addition, a lot of other internal functions in the Engine Control Unit (ECU) also depend on such sensors’ functionalities. Thus, it becomes imperative to study the potential impact of higher field emissions on the immunity behaviour of the sensors. In this paper, we will study the immunity behaviour of such an automotive capacitive touch-sensing integrated circuit (IC) and its impact on the application of the same. A Direct Power Injection (DPI) test is conducted on the IC and the immunity behaviour is extracted by simulation methodology. In order to enhance the overall immunity performance in a practical application, a reference design board is developed, and the immunity performance is measured by the Bulk Current Injection (BCI) technique. In addition, the measured BCI test results are simulated and validated based on the extracted immunity behaviour of the IC. This study shows that the immunity performance of the sensors’ circuitry can be effectively predicted by a simulation-based approach, thereby allowing system engineers to utilize this approach in early design stages to predict possible immunity EMI/EMC test failures and make necessary changes in design to avoid multiple PCB design and EMI/EMC testing iterations.