Valente Virgilio, Demosthenous Andreas
Annu Int Conf IEEE Eng Med Biol Soc. 2015 Aug;2015:885-8. doi: 10.1109/EMBC.2015.7318504.
This paper presents the preliminary design and simulation of a flexible and programmable analog front-end (AFE) circuit with current and voltage readout capabilities for electric impedance spectroscopy (EIS). The AFE is part of a fully integrated multifrequency EIS platform. The current readout comprises of a transimpedance stage and an automatic gain control (AGC) unit designed to accommodate impedance changes larger than 3 order of magnitude. The AGC is based on a dynamic peak detector that tracks changes in the input current over time and regulates the gain of a programmable gain amplifier in order to optimise the signal-to-noise ratio. The system works up to 1 MHz. The voltage readout consists of a 2 stages of fully differential current-feedback instrumentation amplifier which provide 100 dB of CMRR and a programmable gain up to 20 V/V per stage with a bandwidth in excess of 10MHz.
本文介绍了一种用于电阻抗谱（EIS）的具有电流和电压读出功能的灵活可编程模拟前端（AFE）电路的初步设计与仿真。该AFE是一个完全集成的多频EIS平台的一部分。电流读出部分由一个跨阻级和一个自动增益控制（AGC）单元组成，该AGC单元设计用于适应大于3个数量级的阻抗变化。AGC基于一个动态峰值检测器，它跟踪输入电流随时间的变化，并调节可编程增益放大器的增益，以优化信噪比。该系统工作频率高达1MHz。电压读出部分由两级全差分电流反馈仪表放大器组成，每级提供100dB的共模抑制比（CMRR）和高达20V/V的可编程增益，带宽超过10MHz。
