具自動校正之轉導電容濾波器

本論文利用五階Elliptic轉導電容低通濾波器，再用合成濾波器之技巧來達到帶通濾波器，主要應用於生醫電路。為了將濾波器之被動元件整合至晶片內部，產生的問題即是被動元件的誤差，導致電路效能不理想。本論文在濾波器電路加上自動校正電容電路，即可降低因電容製程誤差、製程飄移、電源電壓變異及溫度改變造成電路效能不理想的問題。濾波器的運算轉導放大器，本論文的架構選擇是綜合先前技術的優缺點，經由評估後，最後運用全差動放大器(Fully Differential)之轉導放大器，為了避免輸出兩端因不匹配導致其電壓不同，因此，加入共模迴授(Come-mode-feedback)技巧，可由負迴授迴路來產生控制電壓進而控制主電路之輸出共模電壓準位，輸入部分運用源極退化技巧，提高轉導放大器之線性度，同時輸入部分亦增加交叉耦合(Cross-coupling)技巧，避免輸入抵補電壓(Offset voltage)影響轉導值。本篇論文中心頻率為450kHz，動態範圍為35dB，此晶片是由TSMC 0.18um 製程製作，核心面積為0.76x0.97 mm2

關鍵字

Elliptic濾波器:轉導電容濾波器:合成濾波器:帶通濾波器:自動校正電容電路

並列摘要

This paper proposes a fifth-order Elliptic operational transconductance amplifier-capacitor (OTA-C) low-pass filter using the complex filter techniques to implement a band-pass filter. Integrating the passive components on-chip will result in frequency error due to the effect of process variations. For this reason, a filter circuit with automatic calibration scheme will be independent on process, voltage and temperature variations. In this work, the passive components are integrated on-chip. The center frequency is 450 kHz and the dynamic range is 35dB. The chip is implemented using TSMC 0.18um 1P6M CMOS process with chip area of 0.76x0.97 mm2 and the total power consumption is 0.14mW.

並列關鍵字

Fifth-order elliptic filter:OTA-C low-pass filter:Complex filter:Band-pass filter:Automatic calibration scheme circuit

參考文獻

[1]P. E Allen and D. R Hoolberg, CMOS Analog Circuit Design, New York: Oxford. 2002.

[4]E. Vittoz and J. Fellrath. “CMOS Analog Integrated Circuits Based on Weak Inversion Operation,” IEEE J. Solid-State Circuits, vol. 12, no. 3, pp. 224-231, Jun. 1977.

[5]D. R. Welland, “A digital read/write channel with EEPR4 detection,” In proc. IEEE Int. Solid-State Circuits Conf. Aug. 1994, pp. 276-277.

[6]A. Lewinski, and Jose Silva-Martinez, “OTA linearity enhancement technique for high frequency applications with IM3 below –65 dB,” IEEE Trans. Circuits Sys. II, Exp. Briefs, vol. 51, no. 10, pp. 542-548, Oct. 2004.

[7]J. Silva-Martinez, M. S. J. Stayert, and W. M. C. Sansen, “A large-signal very low-distortion transconductor for high-frequency continuous-time filter,” IEEE J.Solid-State Circuits, vol. 26, no. 7, pp. 946-955, July 1991.

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具自動校正之轉導電容濾波器

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