以運算轉導放大器OTA-C設計電流式三階橢圓濾波電路於高頻操作時非理想效應與改進

Non-ideal Effect and Improvement of the Current-Mode Third-Order High-Frequency OTA-C Elliptic Filter

李香緯(Hsiang-Wei Li)

指導教授 ： ARRAY(0xbd20e10)

中原大學/工學院/電機工程研究所/碩士(2009年)

https://doi.org/10.6840/cycu200900778

摘要

摘 要
以最少主動與被動元件的三階運算轉導放大器及電容器 (Third-Order OTA-C)架構設計，為一個複雜的轉移函數經創新代數分解後而合成，稱為分析合成法 (Analytical Synthesis Method) 。以OTA-C為主要架構電流式的奇數階與偶數階橢圓濾波器，具備了以下三項優點： (1) 使用單端輸入的OTAs; (2) 所有的電容是接地; (3) 使用最少的主動元件，且所有外加電容位置恰好與所有寄生電容的位置相同，吸收了寄生電容，減少寄生效應對整體電路的影響。在積體電路中相同電容大小架構設計需考慮到精準製作的困難度，但這三項優點可得到最低的總寄生值(Parasitics) 及最佳精準的輸出響應。
此三階橢圓濾波電路為使用最少OTA-C元件，並利用OTA-C特性來組合矩陣電路設計方式，研究非理想效應下的頻率響應模擬分析與量測誤差，並在靈敏度變化找到可控制方式來改善高頻時的誤差。從1MHz至10MHz模擬測試，並針對觀察四個轉導值±5%與電容值±5%的靈敏度變化，並依據其特性結果來修正fP的誤差率，將模擬頻率提高至50MHz時確認頻率響應結果。本論文以H-spice軟體進行電路模擬，所使用製程參數為TSMC0.35μm，並於實際模擬結果中分析非理想效應影響。

關鍵字

使用最少主動及被動元件 ； 電流式三階橢圓濾波器 ； 靈敏度調整 ； OTA-C

並列摘要

Abstract
The third-order operational transconductance amplifier and capacitor (OTA-C) elliptic filter structures use the minimum number of active and passive components. It was a complicated transfer function by an innovative algebraic decomposition, i.e., a new analytical synthesis method. A current mode odd-order and even-order OTA-C elliptic filter structure having three following advantages: 1)all the OTAs have single-ended inputs; 2)all the capacitors are grounded; 3) the minimum active and passive components are used. all the parasitic capacitances have the same position so those of given capacitors in the realized circuits that absorbed the shunt parasitic capacitance effect. An OTA-C structure is designed taking into account the difficulty of precisely fabricating capacitances in integrated circuits. Although that limit, the three advantages lead to the lowest total parasitic and to the most precise output response.
The three-order elliptic filter use the minimum components, to utilize the OTA-C characteristic combine the circuit design by matrix method. Research the analyzed simulation and error measurement under non-ideal response. To improve high frequency error and find out controllable method in sensitivity test. To observe four transconductance ±5% and three capacitors ±5% error deviations from 1MHz to 10 MHz simulate testing, and based on the deviations trend to improve the fp error ratio. After that ,confirm the frequency response when raise up the frequency to 50 MHz . Finally, the H-spice simulation with TSMC0.35μm process verifies the theoretical and simulate the result under the non-ideal effect .

並列關鍵字

OTA-C ； The current-mode elliptic filter ； sensitivity tuni

參考文獻

[23] 王俊傑，“具有最少元件的電流式OTA-C三階橢圓濾波電路於高頻操作時非理想效應之研究與改進“，中原大學電機工程研究所，2006。

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[3] C. M. Chang; Al-Hashimi, B.M. “New high-order filter structures using only single-ended-input OTAs and grounded capacitors”, IEEE transactions on circuit and systems-II, vol. 51, pp. 458-463, Sept. 2004.

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