EMC design of FPC for automotive instrument display

Abstract

The digitization of our world has been a forward march for years now, compliance to electromagnetic compatibility (EMC) standard has become an essential part for automotive electronic products. For automotive instrument display system, flexible printed circuit (FPC) which serves as an interconnect between the printed circuit board and display module can behave like an antenna, radiating undesired emissions and degrading the performance of other electronic components if its EMC design is not properly considered. This paper describes the radiated emission studies on the bending of the FPC as the position of the FPC connectors were not directly aligned at most of the time and bending of the FPC is required. In this project, isolated clock drivers with various EMC design such as ground guard trace and spread spectrum technique is also designed and fabricated to drive the clock signal into the thin film transistor (TFT) display through the FPC. Besides that, the development and testing of the automotive subsystem development usually require costly facilities. Validation of the radiated emission simulation which can perform various what-ifs scenario and derive as a cost-effective solution is investigated in this report as well. Through this study, recommendations of the suitable EMC design of the FPC and clock driver will be provided and a correlation between simulation and actual measurement will be established.