Emi analysis of the LCD panel considering the display driver IC operations

Abstract

Electromagnetic interference (EMI) has become more and more important in the electronics systems especially for household appliance. This paper describes a fast and accurate system-level simulation method for the EMI analysis of liquid crystal display (LCD) panel taking into account the operation of full chip level display driver IC (DDI) as an EMI aggressor. Because a LCD panel consists of several PCBs, chips and passive elements, the effort to model the network smaller and the simulation vector shorter is so critical for the analysis to be successful. The modeling aims not only to reduce the network size by considering the operating frequency and switching capability of each component but also to compact the simulation vector in a short period by analyzing the test mode image which has the busiest activity and makes a peak EMI noise level. This method is applied to estimate and suppress EMI noise due to the 8-bit DDI in 40 LCD panel system. As a result, the circuit size of DDI is reduced about 95% and the loss of model accuracy is within 10%. The EMI noise level is decreased by more than 5 dB by finding the optimal point of decoupling capacitor. This method is useful for modeling a large system and analyzing major EMI problem in system-level as well as chip-level.