Novel 10-Bit Impedance-to-Digital Converter for Electrochemical Impedance Spectroscopy Measurements

Abstract

Electrochemical impedance spectroscopy (EIS) is a widely used technique in biomedical and chemical analysis. A novel 10-bit impedance-to-digital converter (IDC), which can measure and directly convert the magnitude and phase of impedance to digital codes, is proposed for the EIS measurement system. The proposed IDC is composed of a magnitude-to-digital converter (MDC) and a phase-to-digital converter (PDC). The proposed IDC was designed and fabricated using a 0.35 [Formula: see text] 2P4M mixed-signal polycide process, and the core area is only 0.07 mm. Moreover, it can work over a very wide frequency range (0.1 mHz-100 kHz), and has excellent accuracy. According to the measured results, the DNL of the MDC is within -0.3/+0.3 LSB, and the INL is around -3/+1 LSB. Moreover, an EIS measurement system, which is composed of the proposed IDC chip and some other commercial chips, is built to measure ZoBell's and melatonin solutions for validating the function of the proposed IDC.

CMOS Interfaces for Internet-of-Wearables Electrochemical Sensors: Trends and Challenges

“…Such a solution [186] represents an FFT/FRA hybrid approach and allows for relaxed DSP requirements with respect to pure FFT based approaches, but sinusoidal excitation and the execution of a frequency scan are necessary as in FRA. As an alternative to extracting the I and Q components, separate magnitude and phase estimation has been demonstrated to be feasible [187].…”

A Multichannel FRA-Based Impedance Spectrometry Analyzer Based on a Low-Cost Multicore Microcontroller

“…In order to reduce electronics complexity, alternative EIS approaches are based on the direct transform of impedance to digital values using impedance-to-digital or dual-slope multiplying ADC (DS-MADC) techniques, achieving accuracies below 10 bits [22,23]. With the goal of further reduce electronics complexity, in order to attain a self-contained low-cost measurement system that renders a true portability while preserving high recovery performance, this paper proposes the complete digitalization of the EIS system through a microcontroller-based FRA implementation, applied to impedance spectroscopy for frequencies in the range of cellular characterization, from 1.1 mHz to 10 kHz.…”

A Multitone Analysis for Bioimpedance Spectroscopy using Minimal Digital Ressource

“…Some are based on "single-tone" signals while the others use "multi-tone" signals. First methods use a pure frequency sine wave to make the measurement [5], [6], [7]. They benefit from a very simple analysis that can consist in synchronous demodulation.…”