一個新型應用於生醫系統之類比前端電路

A New Analog Front-End Circuit for Biomedical Applications

陳鈺融(Yu-Junk Chen)

指導教授 ： 黃育賢 ； 陳建中

國立臺北科技大學/電資學院/電腦與通訊研究所/碩士(2008年)

https://doi.org/10.6841/NTUT.2008.00521

摘要

本論文主要的研究重點在於生醫前端電路上低功率消耗和提高電路效能。低功率消耗和低雜訊的發展變成在生醫應用的目標。而用於生醫系統之計錄器，如ECG/EEG等記錄器，其效能相當依賴系統中的儀表放大器。儀表放大器功用在於將微小的信號放大到較大的信號。然而，這些系統相當容易受到雜訊和共模電壓受到干擾，這是因為雜訊通常都大於輸入信號。在傳統的電路上，電流式儀表放大器有較好的共模拒斥比來抵抗雜訊，但是卻有較高的閃爍雜訊。另一方面在電路中電流鏡不匹配也會造成共模拒斥比下降。
在此論文中，以差動差分傳輸器來實現電流式儀表放大器，同時加入截波技術來消除來自閃爍雜訊的干擾。並且在電流式電路之電流鏡映射上使用疊接方式來降低共模電壓干擾。除此之外，電流式儀表放大器的高輸入阻抗可以降低負載效應。之後，由交換式電容電路組成的二階低通濾器來濾除頻寬外的雜訊，再用二階三角積分調變器做信號處理。以上三個電路中採用台積電0.35微米2P4M的製程技術在供應電壓±0.9V來完成。

關鍵字

差動差分電流傳輸器 ； 儀表放大器 ； 濾波器 ； 三角積分調變器

並列摘要

This thesis is focused on investigating the low power consumption in biomedical front-end circuit; besides, performance of the circuit has been raise. The development of low power and low noise design has become the focus of biomedical applications. The performance of biomedical recording system depends on the instrumentation amplifier, such as Electrocardiogram or Electroencephalogram recording. It is to amplify very small voltage signal to large voltage amplitudes; nonetheless, the system is sensitively associated with noise and common-mode voltage because of these signals are usually greater than input signal. In traditional circuits, the current-mode instrumentation amplifier (CMIA) has the advantage for high CMRR performance, but it exhibits high significantly 1/f noise. On the other hand, the current mirror of the CMIA is mismatch and will be lower the CMRR.
In this thesis, CMIA using differential difference current conveyor, the interference of noise from 1/f noise can be removed by chopper-stabilized technology. The interference of common-mode voltage is reduced by the current-mode circuit that uses the cascode current mirror. Besides, the load effect is reduced by the high input impedance of the CMIA. The signal outside the bandwidth is removed by second order low-pass filter using switched-capacitor circuit, and the inner bandwidth counterpart is processed by second order sigma-delta modulator. For three circuits above, whose power supplies are ±0.9V, is implemented using TSMC 0.35um process.

並列關鍵字

Differential difference current conveyor ； Instrumentation Amplifier ； Filter ； Sigma-Delta Modulator.

參考文獻

[10] 黃照宏，以電流式主動元件為基礎之濾波器與振盪器的設計與實現，碩士論文，國立台北科技大學電腦與通訊研究所，台北，2007.

[32] 楊盛惟，應用於數位音頻系統之微功率開關電容三階三角積分調變器設計，碩士論文，國立台北科技大學電腦與通訊研究所，台北，2007.

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