A Potentiostat-Based Wide-DR Multi-Sensor Integrated Interface for Heterogeneous Chemical Sensor Applications

Abstract

A potentiostat-based wide dynamic range (DR) multi-sensor integrated interface is presented for heterogeneous chemical sensor applications. For versatility across various sensor kinds, a reconfigurable frontend structure based on the potentiostat is proposed to provide wide DR performance for multiple sensor types of electrochemical, chemo-resistive, and FET-based. Each operation mode for different sensor types is designed to support adaptive calibration capabilities on baseline, offset, and sensitivity. It is also designed to support selectable digital conversion methods for optimal conversion speed and resolution, depending on application requirements. In the electrochemical mode, bi-directional operation is implemented to support various detection methods including cyclic voltammetry and chronoamperometry. In the chemo-resistive mode, the DR performance is much extended especially in low-resistance range. Its read-out integrated circuit was fabricated in a 0.18- $\mu $ m CMOS process. For system-level feasibility, a wireless sensor prototype with inhouse sensor devices was manufactured and experimentally verified, achieving measured DRs of 164.5 dB for current-type and 188 dB for resistive-type sensors.