應用於高密度神經感測之低雜訊截波穩定型之開迴路神經訊號放大器

Abstract

本論文主要目的在設計與實現一個低雜訊、低功耗六十四通道電生理訊號類比前端放大電路研究，可應用於各類微弱的生理訊號處理以及醫療儀器方面使用。所提出的全整合類比前端電路在處理來自輸入的生理訊號所產生的直流電壓偏移以及低頻雜訊並非採用在輸入端放置大電容或是增加輸入元件面積的方法，而是使用數位補償的電路去消除直流偏移和截波穩定的技術去消除低頻雜訊以達到低雜訊且能量最佳化的目標；為了更進一步的去縮小電路的面積而採用四個通道共用一組數位補償電路的方法使得一個通道的面積只有0.03mm2，則可在面積方面相較於其他相同應用下的電路有極大的優勢。本論文設計的六十四通道配有數位補償的類比前端電路透過國家晶片系統設計中心使用tsmc 90nm CMOS 製成來製作晶片。模擬的結果顯示此類比前端電路可在四個通道總和面積為358.02μm × 358.86μm的情況下每個通道增益值達到57.9dB且功率消耗為9.848μW的結果；而其工作的頻寬從7.74Hz到4.18kHz。此外，CMRR與PSRR在沒有來自輸入端的直流偏壓的情況下分別可達到99.1dB以及65.13dB。

This thesis, aims to design and implement a low noise, low power-consumption 64-channel electrophysiological signal analog front-end amplifier (AFE), which can be applied to various types of weak physiological signal acquisition and medical instrumentation systems applications. Instead of using big capacitors at the input node to block the dc offset voltage and enlarging the input device area to reduce the low frequency noise from input neural signal, this fully integrated analog front-end circuit adopts digital compensation circuit to cancel the offset and chopper stabilization technique to reduce the noise for achieving low-noise and energy efficiency. To further reduce area of the circuit, adopt four channel share one digital compensation circuit result in only 0.03mm2 for one channel makes it have great advantages than other design. This thesis describes the design of 64-channel AFE with digital compensation through the National Chip Implementation Center tsmc 90nm CMOS process. The simulation results show that the area of four channels AFE is 358.02μm × 358.86μm and realize 57.9dB gain with 9.848μW for each channel. The bandwidth of the AFE is from 7.74Hz to 4.18kHz. Furthermore, the CMRR and PSRR can reach 99.1dB and 65.13dB when there is no dc offset from the input.