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An Efficient Pulse Width Measurement Method using Multiphase Clock Signals for Capacitive Touch Switches

  • Seong, Kwang-Su
  • Received : 2012.10.09
  • Accepted : 2013.02.22
  • Published : 2013.07.01

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.

Keywords

Capacitive touch switch;Multiphase clock signal;Pulse width measurement;Ring oscillator

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Acknowledgement

Supported by : Yeungnam University