A 15-nW per Sensor Interference-Immune Readout IC for Capacitive Touch Sensors

Said Hussaini, Hui Jiang, Paul Walsh, Dermot MacSweeney, Kofi Makinwa

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

This paper presents a readout IC that uses an asynchronous capacitance-to-digital-converter (CDC) to digitize the capacitance of a touch sensor. A power-efficient tracking algorithm ensures that the CDC consumes negligible power consumption in the absence of touch events. To facilitate its use in wake-on-touch applications, the CDC can be periodically triggered by a co-integrated ultra-low-power relaxation oscillator. At a 38-Hz scan rate, the readout IC consumes 15 nW per touch sensor, which is the lowest reported to date.

Original languageEnglish
Article number8691537
Pages (from-to)1874-1882
Number of pages9
JournalIEEE Journal of Solid-State Circuits
Volume54
Issue number7
DOIs
Publication statusPublished - 2019

Keywords

  • Asynchronous tracking logic
  • capacitance-to-digital-converter (CDC)
  • self-capacitance sensor
  • stand-alone touch sensor
  • ultra-low-power oscillator

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