應用於生醫系統之新型低功率高共模拒斥比儀表放大器

New Low-Power High-CMRR Instrumentation Amplifier for Biomedical System Application

潘聖文(Sheng-Wen Pan) ； 莊炯承(Chiung-Cheng Chuang) ； 洪君維(Jiun-Wei Horng) ； 徐瑋澤(Woei-Tzer Shyu)

《先進工程學刊》 3卷4期 (2008/10) Pp. 339-344

https://doi.org/10.29948/JAE.200810.0011

摘要

本篇論文針對生理訊號前端處理電路提出一個新型的低功率、高共模拒斥比(Common mode reject ratio, CMRR)的CMOS電流式儀表放大器。其運算放大器(Operation amplifier, OPA)輸入級使用互補式差動對以達寬共模輸入範圍。OPA的輸出串接寬擺幅電流鏡(High swing current mirror)，可操作在低電壓並得到寬的輸出擺幅。此外訊號由電壓轉換為電流，電流式訊號處理可使CMRR 免受匹配電阻的影響。此電路在單電源1.8 V的電壓操作下，功率消耗僅88 uW，且CMRR 可達157.84 dB。電路是在台灣積體電路製造公司(TSMC) 0.35 μm 2P4M CMOS 製程下模擬產生。

關鍵字

低功率 ； 高共模拒斥比 ； 軌對軌輸入／輸出 ； 儀表放大器

並列摘要

This work presents a low power CMOS current-mode instrumentation amplifier (CMIA) with a very high Common Mode Rejection Ratio (CMRR), used as an analog front-end circuitry for processing of biological signals. In order to reach a wide input common mode range (ICMR), the input stage operational amplifier (OPA) uses a complementary differential pair configuration. The OPA cascade high swing current mirror realizes wide output swing at low voltages. The input voltage signal is converted to current. Signal processing using the current mode increases the CMRR due to the fact that it has more flexibility in resistor matching. The whole circuit operates with a single 1.8 V power supply. It is implemented in TSMC 0.35 um 2P4M CMOS technology that consumes only 88 uW and a high CMRR of about 157.84 dB.

並列關鍵字

low power ； high CMRR ； rail-to-rail input and output ； instrumentation Amplifier