A highly noise-immune touch controller using Filtered-Delta-Integration and a charge-interpolation technique for 10.1-inch capacitive touch-screen panels

Abstract

Capacitive touch-screen panels (TSPs) are widely used in recent high-end mobile products on the basis of their high quality of touch features, as well as superior visibility and durability [1-5]. Capacitive TSPs can be classified into self-capacitance [1,2] or mutual-capacitance [3-5] types, according to the sensing mechanism. Compared with the self-capacitance types, which offer low cost and high scan frequency from the simple line-sensing scheme, the mutual-capacitance types, which read out all sensor pixels, are presently widely preferred due to their multi-touch capabilities. However, the reduced sensing time for each sensor makes it difficult to achieve a high signal-to-noise ratio (SNR). Therefore, good noise performance in the analog front-end of the touch controller is essential for mutual-capacitance type TSPs.