A Microwatt Dual Mode Electrochemical Sensing Current Readout with Current Reducer Ramp Waveform Generation

Yi Chia Chen, Shao Yung Lu, Yu-Te Liao*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

An electrochemical sensing chip with an integrated current-reducer pattern generator and a current-mirror based low-noise chopper-stabilization potentiostat circuit is presented. The pattern generator, utilizing the current reducer technique and pseudo resistors, creates a sub-Hz ramp signal for the cyclic voltammetric (CV) measurement without large-size passive components. The proposed design adopts the chopper-stabilization and low-noise biasing technique for the potentiostat and a counter-based time-to-digital converter to reduce the amplitude noise effects and to convert the sensing current signal to digital codes for further data processing. The design is fabricated using a 0.18-&#x03BC;m CMOS process and achieves a 41pA current resolution in the current range of <formula><tex>$\pm$</tex></formula> 5&#x03BC;A while maintaining the R<formula><tex>$^{2}$</tex></formula> linearity of 0.998. The system consumes 16&#x03BC;W from a 1.2V supply when a 5&#x03BC;A sensing current is detected. The power efficiency of the readout interface is 0.31, and the sensing current dynamic range is 108dB. The design is fully integrated into a single chip and is successfully tested in the dual-mode (CA/CV) measurements with commercial gold electrodes in a potassium ferricyanide solution in sub-millimolar concentrations.

Keywords

  • current-reduced ramp generator
  • Cyclic voltammetry
  • electrochemical sensing
  • low power
  • power-efficient

Fingerprint

Dive into the research topics of 'A Microwatt Dual Mode Electrochemical Sensing Current Readout with Current Reducer Ramp Waveform Generation'. Together they form a unique fingerprint.

Cite this