Stevenazzi Lorenzo, Baschirotto Andrea, Zanotto Giorgio, Vallicelli Elia Arturo, De Matteis Marcello
Department of Physics, University of Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy.
Section of Milano Bicocca, National Institute of Nuclear Physics, Piazza della Scienza 3, 20126 Milano, Italy.
Bioengineering (Basel). 2022 Jan 18;9(2):42. doi: 10.3390/bioengineering9020042.
This paper presents specific noise minimization strategies to be adopted in silicon-cell interfaces. For this objective, a complete and general model for the analog processing of the signal coming from cell-silicon junctions is presented. This model will then be described at the level of the single stages and of the fundamental parameters that characterize them (bandwidth, gain and noise). Thanks to a few design equations, it will therefore be possible to simulate the behavior of a time-division multiplexed acquisition channel, including the most relevant parameters for signal processing, such as amplification (or power of the analog signal) and noise. This model has the undoubted advantage of being particularly simple to simulate and implement, while maintaining high accuracy in estimating the signal quality (i.e., the signal-to-noise ratio, SNR). Thanks to the simulation results of the model, it will be possible to set an optimal operating point for the front-end to minimize the artifacts introduced by the time-division multiplexing (TDM) scheme and to maximize the SNR at the a-to-d converter input. The proposed results provide an SNR of 12 dB at 10 µV of noise power and 50 µV of signal power (both evaluated at input of the analog front-end, AFE). This is particularly relevant for cell-silicon junctions because it demonstrates that it is possible to detect weak extracellular events (of the order of few µV) without necessarily increasing the total amplification of the front-end (and, therefore, as a first approximation, the dissipated electrical power), while adopting a specific gain distribution through the acquisition chain.
本文介绍了在硅电池接口中采用的特定噪声最小化策略。为此，提出了一个用于对来自电池 - 硅结的信号进行模拟处理的完整通用模型。然后将在单级以及表征它们的基本参数（带宽、增益和噪声）层面描述该模型。借助一些设计方程，因此可以模拟时分复用采集通道的行为，包括信号处理的最相关参数，如放大（或模拟信号的功率）和噪声。该模型具有无疑的优势，即特别易于模拟和实现，同时在估计信号质量（即信噪比，SNR）方面保持高精度。借助该模型的模拟结果，将有可能为前端设置一个最佳工作点，以最小化时分复用（TDM）方案引入的伪像，并在模数转换器输入处最大化SNR。所提出的结果在噪声功率为10 µV和信号功率为50 µV（均在模拟前端，AFE的输入处评估）时提供了12 dB的SNR。这对于电池 - 硅结尤为重要，因为它表明在采用通过采集链的特定增益分布时，无需必然增加前端的总放大倍数（因此，作为一阶近似，即耗散的电功率）就有可能检测到微弱的细胞外事件（几µV量级）。
