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Journal of Sensors
Volume 2015, Article ID 768293, 10 pages
Research Article

Concurrent Driving Method with Fast Scan Rate for Large Mutual Capacitance Touch Screens

Electronic Engineering Department, School of Electrical Engineering and Computer Science, Chungbuk National University, 1, Chungdae-ro, Seowon-gu, Cheongju-si, Chungcheongbuk-do 362-763, Republic of Korea

Received 10 April 2015; Accepted 21 June 2015

Academic Editor: Chi Chiu Chan

Copyright © 2015 Mohamed Gamal Ahmed Mohamed and HyungWon Kim. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A novel touch screen control technique is introduced, which scans each frame in two steps of concurrent multichannel driving and differential sensing. The proposed technique substantially increases the scan rate and reduces the ambient noise effectively. It is also extended to a multichip architecture to support excessively large touch screens with great scan rate improvement. The proposed method has been implemented using 0.18 μm CMOS TowerJazz process and tested with FPGA and AFE board connecting a 23-inch touch screen. Experimental results show a scan rate improvement of up to 23.8 times and an SNR improvement of 24.6 dB over the conventional method.