- 學位論文
OTA-C與CCCII-C電流式高階MISOC濾波電路之設計
Design of Current-Mode High-Order OTA-C and CCCII-C MISOC Filter Structures
摘要
電流式電路的設計在近十五年來蓬勃的發展；在這些年當中，也逐一證實電流式電路比電壓式電路有較好的精準度。由於運算轉導放大器（Operational Transconductance Amplifier, OTA）與第二代電流控制傳輸器（Second-generation Current Controlled Conveyor, CCCII）可藉由一偏壓電流改變其內部轉導值或本質電阻（intrinsic resistance），所以在設計電路時，無需外加電阻器與考慮電阻器接地的問題；本論文就是利用這兩種主動元件的這個優良特性，成功的提出兩個N階萬用濾波電路的架構。這兩個電路架構使用最少的主、被動元件（N個），所使用的主、被動元件均接地的優點有利於電路的積體化。 本論文以先前學者所提出設計N階濾波電路的方法：信號流程圖法（signal-flow-graph）與建構式方塊法（building block），成功的提出多輸入與單輸出（MISOC）架構的高階濾波電路。在同一電路的架構下，同時可實現五種不同的濾波（即高通、低通、帶通、帶拒與全通）信號。所提出的電路架構，可分別以OTA-C或CCCII-C完成電路設計。在驗證方面，我們以相同頻率、相同階數的條件，去比較OTA-C與CCCII-C電路所呈現的濾波效果、靈敏度分析與雜訊響應。模擬所使用的工具是HSPICE，並以TSMC025 Level49的製程參數為模擬依據，作為電路晶片化前的考量。經過模擬比較後，雖然CCCII-C電路在高頻、高階所表現的結果略比OTA-C電路遜色；不過兩者的模擬值與Matlab所估算的理論值都還相當的吻合。
並列摘要
In recent one and a half decades, the current-mode circuit is proved to be much more precise than its voltage-mode counter part. Since the transconductance of an operational transconductance amplifier (OTA) and the inner intrinsic resistance at terminal x of a second-generation current controlled conveyor (CCCII) are electronically adjusted by the internal bias current, no resistors in the OTA-C or CCCII-C circuit become an important advantage in the active filter design. In the thesis, the current-mode high order OTA-C and CCCII-C MISOC (multi-input single-output circuit) structures are presented. The least number of active and passive elements, N, for n-th order filters is used in the design. Because all of the active and passive elements are grounded, it is attractive for integration and reduces the effect of parasitic capacitors. In the beginning, two powerful active elements, CCCIIs and OTAs, are introduced. Two circuit design approaches, signal-flow-graph and the use of building block, are used in the thesis. Then a multi-input and single-output circuit structure is successfully developed to realize the current-mode high-order universal (i.e., high-pass, low-pass, band-pass, band-reject and all-pass) filters. The proposed filter structure is implemented by the OTA-C or CCCII-C circuits. H-Spice simulation with TSMC025 parameter process validates the theory predictions for both OTA-C and CCCII-C circuit implementations, although the former is more precise in high frequency performance than the latter.