以電流迴授放大器為主動元件設計電壓式萬用濾波器之研究與分析

Design and Analysis of Universal Voltage-Mode Filters Employing CFA

林益全(Yi-Chuan Lin)

指導教授 ： 張俊明

中原大學/工學院/電機工程研究所/碩士(2008年)

https://doi.org/10.6840/cycu200800212

摘要

在類比濾波電路設計領域上，其電路首要重視的就是輸出訊號的精準度，使輸出訊號準確的操作在我們所預定的頻率，為設計電路第一目標。但經常發現以往設計的電路中，為了輸出更精準或彌補電路缺失不斷加補償電路，而將電路複雜了。在科技日新月異的現代，對電路要求亦加卓越，不僅要求電路的精準度，也強調電路需簡單化，以降低成本，提高電路的競爭力，此皆為設計電路須考慮要素。
近年來學者常以電流式主動元件設計類比電路，由於電流式主動元件所設計之電路，已被證明具有較高之頻寬、較大之動態範圍、較大之線性範圍、較小之功率損耗及較簡單之電路結構，故早已為學術界與工業界所肯定，因此利用電流傳輸器(Current Conveyor，簡稱CC)及電流回授放大器(Current Feedback Amplifier，簡稱CFA)等電流式主動元件來設計濾波電路，已受到相當之重視。本文所提出之電路主要使用電流式主動元件：電流回授放大器來設計二階的萬用濾波電路，即包含低通、高通、帶通、帶拒及全通五種功能的濾波電路。
以單一個電流回授放大器為主動元件設計新的電壓式三輸入、單輸出萬用濾波電路，並與目前已發表之電路相比較，本文所提電路，僅使用一個負型電流回授放大器、兩個電容器及兩個電阻器，為目前二階萬用濾波器最少元件且無需任何阻抗匹配條件，即可完成低通、高通、帶通、帶拒及全通濾波電路的設計。最少元件使得功率消耗低、雜訊較少、電路面積小及低成本，相當有利於電路之積體化製造。主要優點不但輸出精準、電路精簡及低成本，同時具有主動元件及被動元件低敏感度之優點，藉此電路根據各元件之敏感度作調整(tuning)，將電路的操作頻率（f3dB）更加準確、電路響應的最大值（peak）趨近於理想。
最後，對於本論文所提之電路，均以H-spice軟體進行電路模擬，所使用製程參數為TSMC035μm，並於實際模擬結果與理論之間相互得到驗證。

關鍵字

類比濾波電路設計 ； 全通濾波器 ； 低通濾波器 ； 帶拒濾波器 ； 高通濾波器 ； 主動濾波器 ； 帶通濾波器

並列摘要

In analogy filter circuit design, the accuracy of output signal takes the most importance in electrical circuits where the first priority is to operate the output signal in the desired frequency. However, for output accuracy and circuit compensation often complicate the electrical circuits. With the improvement in technologies, electrical circuits not only require output accuracy but also emphasized the simplicity in order achieve cost down and higher competitiveness for these are the essential elements in circuit design.
It has been verified that the circuits constructed by active current mode elements have the advantage of higher signal bandwidths, larger dynamic range, greater linearity, less power dissipation and simpler circuit structure. So, the circuits which are designed by employing the current conveyor and the current feedback amplifier have been received considerable attention recently.
The realization of the second-order universal (low-pass, band-pass, high-pass, band-reject, and all-pass) active-voltage filter using a single minus-type current feedback amplifier (CFA), two capacitors, and two resistors is proposed in this thesis. Compared with the published paper, the circuit offers the following advantageous features: The proposed circuit uses a single CFA, two resistors and capacitors. No requirement of circuit component matches conditions. It can simultaneously realize low-pass, high-pass, band-pass, notch and all-pass filter signals. And less power consumption, simpler circuit structure, reduce the noise and cost, low active and passive sensitivities ideal for integration. We can make the simulation result much closer to the ideal one in accordance with the passive sensitivities.
Finally, the simulation results validate and the theory predictions of the proposed circuit are verified very well by using TSMC035 H-spice simulation.

並列關鍵字

low-pass filters ； continuous-time filters ； band-reject filters ； all-pass filters ； active filters ； analog circuit design ； band-pass filters ； high-pass filters

參考文獻

[1] K. C. Smith and A. Sedra, ‘‘The current conveyor-a new circuit building block,’’ IEEE Proc, vol. 56, pp. 1368-1369, 1968.

[2] B. Wilson, “Constant bandwidth voltage amplification using current conveyor,” Int. J. Electronics, vol. 65, no.5, pp. 983-988, 1988.

[3] Sedra/Smith,: “Microelectronic Circuits”, Third Edition.

[4] K. C. Smith and A. Sedra, “A second-generation current conveyor and it’s applications,” IEEE Trans., CT-17, pp. 132-134, 1970.

[5] A. Fabra, O. Saaid, F. Wiest, and C. Boucheron, “ High frequency applications based on a new current controlled conveyor, ”IEEE Trans. on Circuit and System-I, vol. 43, no. 2, pp. 82-91, 1996.