Circuit design for broad band EMI reduction in LCD driver IC

Abstract

In this paper, the circuit for electromagnetic interface (EMI) reduction in liquid crystal display (LCD) is proposed. The segmented driver circuit and cascode level shifter are employed in the column driver IC for the EMI reduction. The proposed column driver IC reduces the switching peak current in LCD panel by adopting the segmented operation in data latch. It provides an oscillating transient current with significantly reduced peak currents. The column driver IC and clock controller are integrated in 0.35 μm CMOS technology with 1-poly and 4-metal process. The simulation test shows that the proposed column driver circuit for LCD driver IC significantly reduces EMI noise level by more than 15 dB with 20 segmented operation in data latch at 40 MHz frequency.