Journal of Electrical Engineering and Technology

The Korean Institute of Electrical Engineers (대한전기학회)
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An Efficient Pulse Width Measurement Method using Multiphase Clock Signals for Capacitive Touch Switches

  • Seong, Kwang-Su (Department of Electronic Engineering, Yeungnam University)
  • Received : 2012.10.09
  • Accepted : 2013.02.22
  • Published : 2013.07.01
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Abstract

We propose an efficient method to measure a pulse width using multiphase clock signals generated from a ring oscillator. These clocks, which have the same frequency and are evenly spaced, give multiple rising edges within a clock cycle. Thus, it is possible to measure a pulse width more accurately than with existing single clock-based methods. The proposed method is applied to a capacitive touch switch. Experimental results show that the capacitive touch switch with the proposed method gives a 118 fF resolution, which is 6.4 times higher than that of the touch switch with a single clock-based pulse width measurement method.

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References

  1. Sungsik Lee, Ahra Lee, Chang-Han Je, Myung-Lae Lee, Gunn Hwang, and Chang-Auck Choi, "1.5V SubmW CMOS interface circuit for capacitive sensor applications in ubiquitous sensor networks," ETRI Journal, Vol. 30, Num. 5, pp. 644-652, Oct. 2008. https://doi.org/10.4218/etrij.08.1308.0034
  2. Chul Nam, Young-Gun Pu, and Kang-Yoon Lee, "12x12 capacitive matrix touch sensing unit for SoC SoC application in 0.18um CMOS process," 2012 International SoC design conference (ISOCC), pp. 305-308, Nov. 2009.
  3. Kwang-Su Seong, "A design of full digital capacitive sensing touch key reducing the effects due to the variations of resistance and clock frequency," Journal of the Korean Institute of Illuminating and Electrical Installation Engineers, Vol. 23, No. 4, pp. 39-46, Apr. 2009. https://doi.org/10.5207/JIEIE.2009.23.4.039
  4. Jun Furuta, Chikara Hamanaka, Kazutoshi Kobayashi and Hidetoshi Onodera, "Measurement of neutroninduced SET pulse width using propagation-induced pulse shiringking," IEEE International Reliability Physics Symposium, pp. 5B.2.1-5B.2.5, Apr. 2011.
  5. Ji-Wei Ke, Shi-Yu Huang, and Ding-Ming Kwai, "A high resolution all-digital duty-cycle corrector with a new pulse-width detector," IEEE International Conference of Electron Devices and Solid-State Circuits, pp. 1-4, Dec. 2010.
  6. Adrian S. Nastase, and Ronald L. Nelson, "Fast 5ns pulse width measurement in a high-speed signal integrity test system," International Semiconductor Conference, Vol. 2, pp. 527-530, Oct. 2001.
  7. John O'Dowd, Andreas Callanan, Gabriel Banarie, and Enrique Company-Bosch, "Capacitive sensor interfacing using sigma-delta techniques," The 4th IEEE Conference on Sensors, pp. 951-954, Oct. 2005.
  8. Xuan Zhang, and Alyssa B. Apsel, "A low-power, process and temperature compensated ring oscillator with addition based current source," IEEE Trans. on Circuits and Systems-I, Vol. 58, No. 5, pp. 868-878, May. 2011. https://doi.org/10.1109/TCSI.2010.2092110
  9. Nils Karlsson, "A study of a high-resolution linear circuit for capacitive sensors", IEEE Trans. on Instrumentation and Measurement, Vol. 48, No. 6, pp. 1122-1124. Dec 1999. https://doi.org/10.1109/19.816125