前端放大器電路設計及感測系統整合

Preamplifier Circuits Design and Sensing Systems Integration

陳春豪(Chun-Hao Chen)

指導教授 ： 呂學士

國立臺灣大學/電機資訊學院/電子工程學研究所/博士(2008年)

https://doi.org/10.6342/NTU.2008.02794

摘要

本論文研究前端放大器電路設計及感測器系統整合，目的在降低感測器之成本及縮小其體積，來增加其應用的範圍。縮小體積及降低功率後的感測器將會開啟可攜式或穿戴式健康感測應用。另一方面藉由更先進的半導體製程可降低感測器介面電路的操作電壓及消耗功率。

本研究提出整合數位、類比及射頻電路之系統單晶片(SOC)，使用UMC 0.18 μm製程。此一系統單晶片包含前端放大器、類比數位轉換器、微控制器、無線收發機。前端放大器操作於1.8 V，消耗261 μW。類比數位轉換器(由楊育哲設計)操作於1.8 V，消耗135 μW，取樣率為25 KSample/s。微控制器操作頻率為500 KHz。無線收發機採用振幅移鍵調變(ASK)架構，ASK接收機(由林宥佐設計)操作於0.45 V，消耗1.36 mW，傳輸速率並可達到2 Mbps。而ASK發射機(由陳筱青設計)，操作於1.73 V，消耗19 mW，傳輸速率可達到500 Kbps。ASK收發機皆傳輸於433 MHz。

利用此無線生醫感測系統單晶片與台大應力所黃榮山教授合作，整合C反應蛋白(CRP)蛋白質感測器，達成可無線傳輸之CRP無線生醫感測器。此CRP無線生醫感測器已發表於ISSCC 2006。

在感測器應用中，儀測放大器是相當常用的感測器放大器。為了更進一步降低儀測放大器的消耗功率、縮小面積及降低成本，本研究採用差動減法放大器(Differential Difference Amplifier)來完成低耗功及縮小面積之儀測放大器。首先用0.13 μm CMOS製程，設計一差動減法放大器操作於1.2 V，且消耗功率為2.4 μW。此差動減法放大器的開迴路增益為74.6 dB、單一增益頻率為50 KHz且輸入參考直流偏移電壓為480 μV。

為了更進一步應用，本研究也使用TSMC 0.35 μm製程，實作出數位可調增益之儀測放大器，其可調增益為24-38 dB，消耗18 μW。可與業界之無線胎壓感測器整合，因其可調增益之功能，可針對不同壓力感測器製程變異控制其增益，降低壓力感測器製程變異之損耗。

最後，為降低前端放大器操作電壓，以達到低耗功之目的。本論文亦提出在TSMC 0.35 μm製程下，使用1V操作的低電壓儀測放大器。其單一增益頻率為 2.5 KHz，消耗功率為680 nW。

關鍵字

無線生醫感測器 ； 系統單晶片 ； 儀測放大器 ； 前端放大器 ； 差動減法放大器 ； 虛擬差動放大器 ； 低電壓 ； 低耗功 ； 可程式化增益

並列摘要

The dissertation is a research about preamplifier circuits design and sensing systems integration to reduce the sensor cost and form factor. The lower cost and smaller form factor sensing systems will open new portable/wearable health monitoring applications. On the other hand, the low voltage and low power sensing interface circuits can be realized by the advance of CMOS semiconductor process.

In the first application, a system-on-a-chip (SOC) IC with digital, analog and RF circuits is proposed by using UMC 0.18 μm CMOS process. The SOC IC includes a preamplifier, an analog-to-digital converter (ADC), a micro-controller unit and a RF transceiver. The preamplifier operates at 1.8 V and consumes 261 μW. The ADC (designed by Yu-Che Yang) operates at 1.8 V, consumes 135 μW and has the 25 KSample/s sampling rate. The micro-controller unit operates at 500 KHz. The transceiver uses the ASK architecture and operates at 433 MHz. The ASK receiver (designed by Yu-Tso Lin) operates at 0.45 V, consumes 1.36 mW and has 2 Mbps bit rate. The ASK transmitter (designed by Hsiao-Chin Chen) operates at 1.73 V, consumes 19 mW and has 500 Kbps bit rate.

The bio-medical wireless (BMW) SOC can be integrated with C-reactive proteins (CRP) sensor fabricated by professor Long-Sun Huang’s research group in the Institute of Applied Mechanics, National Taiwan University. This CRP BMW sensor had been published in ISSCC 2006 by invited paper.

In sensor applications, the instrumentation amplifiers (IAs) are usually adopted. To reduce the power consumption, area and cost, we use the differential difference amplifier (DDA) to realize the low power and small area IA. First we use TSMC 0.13 μm CMOS technology to design a DDA operated at 1.2 V and consumed 2.4 μW. The DDA has the 74.6 dB open-loop gain, 50 KHz unity gain frequency and 480 μV input-referred dc offset voltage.

Furthermore, we also use TSMC 0.35 μm CMOS technology to design a programmable gain IA (PGIA). The gain is controlled by three digital bits and is from 24 to 38 dB. The power consumption of the PGIA is 18 μW operated at 3 V. It can be integrated with the wireless tire pressure sensors.

Finally, we proposed a new DDA architecture to reduce the power supply voltage for lower power consumption. The DDA operates at 1 V, consumes 680 nW, has unity gain frequency at 2.5 KHz and fabricated in TSMC 0.35 μm CMOS technology.

並列關鍵字

bio-medical wireless sensor ； system-on-a-chip ； instrumentation amplifier ； preamplifier ； differential difference amplifier ； pseudo-differential amplifier ； low-voltage ； low-power ； programmable gain

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