新型電流式儀表放大器之設計及 應用於生醫系統之類比前端電路

Design of New Current-Mode Instrumentation Amplifier and Analog Front-End Circuit for Biomedical Applications

劉文雄(Wen-Hsiung Liu)

指導教授 ： 黃育賢

國立臺北科技大學/電資學院/電腦與通訊研究所/碩士(2009年)

摘要

本論文主要研究電流式儀表放大器的設計與改進，透過不同的電流式元件所設計出來的儀表放大器，來提高電路效能，所用到的元件有電流傳輸器、運算轉阻放大器、差動差分電流傳輸器、全差動差分電流傳輸器、差動差分運算浮接電流傳輸器。儀表放大器的功用在於將微小的訊號放大，而微弱的輸入訊號受到雜訊的影響非常的大，所以高共模拒斥比會是設計的重點。
本論文也提出了一個新型電流式交換式電容可調濾波器，使用差動差分電流傳輸器去完成，並加入開關透過責任週期去達到可調的效果，合成濾波器的方法有很多種，本濾波器是採用Follow the Leader Feedback 及Cascade 方法構成四階的低通濾波器，最大的頻寬可以達到2 MHz。
最後將儀表放大器及濾波器整合，完成生醫應用的類比前端段路，儀表放大器是由差動差分電流傳輸器完成，由於生醫訊號受雜訊的干擾很大，在電路中加入截波技術來降低低頻的閃爍雜訊，濾波器的部份是用轉導放大器去完成低通交換式電容的可調濾波器，所以低功耗及低雜訊會是設計的重點。
　　本論文的電路是採用台積電0.35微米2P4M的製程技術及台積電0.18微米1P6M製程技術來完成。

關鍵字

電流傳輸器 ； 運算轉阻放大器 ； 差動差分電流傳輸器 ； 全差動差分電流傳輸器 ； 差動差分運算浮接電流傳輸器 ； 儀表放大器 ； 交換式可調濾波器

並列摘要

The design and improvement of instrumentation amplifier is the focus in this thesis, the author used different current conveyors to complete instrumentation amplifiers , and improve the performance of circuits. The elements used are current conveyor、operational transresistence amplifier、differential difference current conveyor、fully differential difference current conveyor and differential difference operational floating current conveyor. The function of instrumentation amplifier is to amplify signal that is small and weak，but weak signal will be affected strongly by noise, therefore the design of high common-mode rejection ratio will be the key point.
A new current-mode switched capacitor tunable filter is designed by differential difference current conveyor in this thesis, it is tunable that by switches with different duty cycle. The way to synthesize filters is so many, follow the leader feedback and cascade is the way to complete four-order filter in this thesis. The max bandwidth is 2 MHz.
Finally, the author synthesizes instrumentation amplifier and filter to complete analog front-end circuit for biomedical applications. The instrumentation amplifier is synthesize by differential difference current conveyor. Due to biomedical signal is weak that would be affected strongly by noise , so chopper technology is used in the circuit to reduce flicker noise at low frequency. The low- pass switched capacitor filter is synthesized by operational transconductance amplifier , the key design of the biomedical system is low power and low noise.
Those designed chips are implemented by TSMC 0.35 um process and TSMC 0.18 um process.

並列關鍵字

Current Conveyor ； Operational Transresistance Amplifier ； Differential Difference Current Conveyor ； Fully Differential Difference Current Conveyor ； Differential Voltage Operational Floating Current Conveyor ； Instrumentation Amplifier ； Switched-Capacitor Tunable Filter

參考文獻

[5] 施俊吉，新型濾波器與量測電路之設計與實現，碩士論文，國立台北科技大學電腦與通訊研究所，台北，2006.

[27] 陳裕融，一個新型應用於生醫系統之類比前端電路，碩士論文，國立台北科技大學電腦與通訊研究所，台北，2008.

[30] 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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