A Compact Fully Dynamic Capacitance-to-Digital Converter with Energy-Efficient Charge Reuse

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

An ultra-low power fully dynamic capacitance-to-digital converter (CDC) that exploits a novel charge reuse technique is proposed. The CDC includes a capacitive bridge as the sensing frontend and an asynchronous SAR ADC for signal digitization. Passive charge sharing between the frontend and ADC is used to enable a fully dynamic operation. Instead of resetting the capacitive bridge (with large sensing and reference capacitors) for each measurement, the charge is maintained and reused over many measurements to save energy. A power gating technique is employed to reduce the stand-by power. As a result, a FoM as low as 4.3fJ/conv-step is achieved for the CDC, which is >3x better than the state-of-the-art. Furthermore, it supports an inherent scaling of power vs. speed with a minimum power of only 44pW and a compact chip area of 6440μm2.

Original languageEnglish
Article number9249050
Pages (from-to)514-517
Number of pages4
JournalIEEE Solid-State Circuits Letters
Volume3
DOIs
Publication statusPublished - 5 Nov 2020

Keywords

  • Capacitance-to-digital converter (CDC)
  • charge reuse
  • dynamic
  • internet-of-things (IoT)
  • power-gating.

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