JOURNAL BROWSE
Search
Advanced SearchSearch Tips
Touch Screen Sensing Circuit with Rotating Auto-Zeroing Offset Cancellation
facebook(new window)  Pirnt(new window) E-mail(new window) Excel Download
 Title & Authors
Touch Screen Sensing Circuit with Rotating Auto-Zeroing Offset Cancellation
Won, Dong-Min; Kim, HyungWon;
  PDF(new window)
 Abstract
In this paper, we present a rotating auto-zeroing offset cancellation technique, which can improve the performance of touch screen sensing circuits. Our target touch screen detection method employs multiple continuous sine waves to achieve a high speed for large touch screens. While conventional auto-zeroing schemes cannot handle such continuous signals properly, the proposed scheme does not suffer from switching noise and provides effective offset cancellation for continuous signals. Experimental results show that the proposed technique improves the signal-to-noise ratio by 14 dB compared to a conventional offset cancellation scheme. For the realistic simulation results, we used Cadence SPECTRE with an accurate TSP model and noise source. We also applied an asymmetric device size (10% MOS size mismatch) to the OP Amp design in order to measure the effectiveness of offset cancellation. We implemented the proposed circuit as part of a touch screen controller system-on-chip by using a Magnachip/SK Hynix 0.18-µm complementary metal-oxide semiconductor (CMOS) process.
 Keywords
Amplifier;Auto-zeroing offset cancellation;Frequency division concurrent sensing (FDCS);Touch screen sensing;
 Language
English
 Cited by
 References
1.
M. G. A. Mohamed. T. W. Cho, and H. Kim, “Efficient multitouch detection algorithm for large touch screen panels,” IEIE Transactions on Smart Processing and Computing, vol. 3, no. 4, pp. 246-250, 2014. crossref(new window)

2.
J. S. Lee, D. H. Yeo, J. Y. Um, E. W. Song, J. Y. Sim, H. J. Park, S. M. Seo, M. H. Shin, D. H. Cha, and H. Lee, "A 10-touch capacitive-touch sensor circuit with the time-domain input-node isolation," SID Symposium Digest of Technical Papers, vol. 43, no. 1, pp, 493-496, 2012. crossref(new window)

3.
I. Seo, T. W. Cho, H. W. Kim, H. G. Jang, and S. W. Lee, "Frequency domain concurrent sensing technique for large touch screen panels," in Proceedings of IEEK Fall Conference, Seoul, Korea, pp. 55-58, 2013.

4.
M. G. A. Mohamed, U. Jang, I. Seo, H. Kim, T. W. Cho, H. K.Chang, and S. Lee, "Efficient algorithm for accurate touch detection of large touch screen panels," in Proceedings of the 18th IEEE International Symposium on Consumer Electronics (ISCE2014), Jeju Island, Korea, pp. 243-244, 2014.

5.
U. Y. Jang and H. Kim, “Frequency division concurrent sensing method for high-speed detection of large touch screens,” Journal of the Korea Institute of Information and Communication Engineering (JKIICE), vol. 19, no. 4, pp. 895-902, 2015. crossref(new window)

6.
I. Seo and H. Kim, “Dual sensing with voltage shifting scherne for high sensitivity touch screen detection,” Journal of the Institute of Electronics and Information Engineers, vol. 52, no. 4, pp. 71-79, 2015. crossref(new window)

7.
C. C. Enz and G. C. Temes, “Circuit techniques for reducing the effects of op-amp imperfections: autozeroing, correlated double sampling, and chopper stabilization,” Proceedings of the IEEE, vol. 84, no. 11, pp. 1584-1614, 1996. crossref(new window)

8.
T. Kugelstadt, “Auto-zero amplifiers ease the design of high-precision circuits,” Analog Applications Journal, vol. 2005, no. 3Q, pp. 19-27, 2005.

9.
Y. C. Kwon and O. K. Kwon, “A precision mismatch measurement technique for integrated capactor array using a switched capacitor amplifier,” IEEE Transactions on Semiconductor Manufacturing, vol. 26, no. 2, pp. 226-232, 2013. crossref(new window)

10.
Analog Devices Inc., Auto-zero amplifiers [Internet], Available: http://www.analog.com/media/en/technicaldocumentation/technical-articles/197774722autozero.whitepaper.doc.

11.
K. H. White, D. R. Lampe, F. C. Blaha, and I. A. Mack, “Characterization of surface channel CCD image arrays at low light levels,” IEEE Journal of Solid-States Circuits, vol. 9, no. 1, pp. 1-12, 1974. crossref(new window)

12.
ATMEL Corporation, “Touch sensors design guide,” ATMEL Corporation, San Jose, CA, Report 10620D-AT42, 2009.

13.
R. W. Brodersen and S. P. Emmons, “Noise in buried channel charge-coupled devices,” IEEE Journal of Solid-States Circuits, vol. 23, no. 2, pp. 215-223, 1976.