Mitigating Camera Interference Arising From RF High Transmit Power: The Role of Common Mode Filters and Receiver Compensation Techniques

Abstract

This paper investigates the challenges and solutions related to Radio Frequency Interference (RFI) in mobile devices equipped with high-resolution cameras, focusing on the Mobile Industry Processor Interface (MIPI) C-PHY interface. The compact design of modern mobile devices makes them susceptible to RFI, which can degrade signal quality and cause visual anomalies. Through simulation-based analysis, we explore the effectiveness of Common Mode Filters (CMFs) in mitigating RFI, highlighting the significance of CMF placement near the Board-to-Board (BTB) connector for enhanced RF immunity and signal integrity. Additionally, we examine receiver compensation techniques to further protect C-PHY signals against RFI. These techniques address the issue of signal imbalances, which can lead to differential-mode interference. The study proposes fine-tuning signal path delays at the CPU receiver end as a strategy to minimize noise, demonstrating improvements in eye diagram metrics. Our findings offer valuable insights into optimizing the placement of CMFs and implementing receiver compensation techniques, contributing to the enhancement of signal integrity and noise reduction in high-speed digital interfaces, thereby ensuring the reliability and performance of camera systems in mobile devices within the RF/EMC/SIPI domain.