差動電壓電流傳輸器組成的振盪器

摘要由於積體電路(IC)的快速發展，及數位電路的設計較簡單，因此類比電路的改善及縮小化，是近年來學者著手的重點。而類比電路中較常使用電壓式主動元件來設計，常見的主動元件是運算放大器(Operational Amplifier ; OPA) ，但是OPA本身會受到增益頻寬積為定值與迴轉率不夠高的限制，所以在高頻應用時其外接回授電路需提高閉迴路增益。所以學者提出用電流式元件來克服此類之問題。此外，由於目前的產業界對於成本的考量日趨嚴苛，如果能夠以較少的元件數而達成相同的結果，即意味產品可以更便宜，那麼將可提高產品的競爭力。較廣泛使用的電流式元件有: 電流傳輸器(Current Conveyor ; CC) 、第二代電流傳輸器(Second-Generation Current Conveyor ; CCII) 、運算轉導放大器(Operational Transconductance Amplifier ; OTA) 、電流回授放大器(Current Feedback Amplifier ; CFA) 、差動電壓電流傳輸器(Differential Voltage Current Conveyor ; DVCC) 。　因第二代電流傳輸器只有端為高阻抗輸入，所以無法直接處理差動訊號。為解決此問題，K. Pal 先生於西元1989年發表了一個新式的應用電路，在CCII的端加上一個增益為一的差動放大器，而成為一個有三個輸入端和兩個輸出端的元件，稱之為DVCCII 。接著Soliman與Elwan兩位學者於西元1997年設計出上述元件的改良電路，改稱為差動電壓電流傳輸器（Differential Voltage Current Conveyor；DVCC）。本文是使用正型差動電壓電流傳輸器(DVCC+)來設計弦波振盪器。相較於先前已經發表之DVCC振盪器，本篇報告提出了使用更少元件的設計方式，一個單一輸出正型DVCC和兩個電容器和兩個電阻器。因為所使用的電容器均接地，所以易實現於積體電路。本文使用聯電0.5um製程參數設計DVCC+，再使用HSpice電路模擬軟體去模擬驗證新型振盪器。被動元件選擇如下：RX=5.1K Ω；R1＝10KΩ；CX=8nF；C1=2nF，振盪頻率為7.879KHz。同時透過Hspice的模擬，此新型振盪器有良好的溫度與電壓操作範圍。

關鍵字

差動電壓電流傳輸器；振盪器

並列摘要

Abstract Due to the huge progress of the integrated circuit technology and the simplification of the digital circuit design, how to improve and reduce analogy circuit becomes the most important topic for scholar recently. So far, the active voltage-mode elements are used in analogy circuit very often. The Operational Amplifier (OPA) is the most popular part of the active voltage-mode elements, but the OPA is limited by its gain-bandwidth-product and slow slew rate in high frequency operations. Hence, scholar provides the active current-mode elements to improve this problem. In addition, cost is the most critical concern in industry. If we can use less components to achieve the same performances, it means that the product is cheaper and more competitive. The common active current-mode elements are Current Conveyor (CC) , Second-Generation Current Conveyor (CCII) , Operational Transconductance Amplifier (OTA) , Current Feedback Amplifier (CFA) , and Differential Voltage Current Conveyor (DVCC) 。 Only terminal Y is the high impedance input of the Second-Generation Current Conveyor (CCII), therefore, it can’t handle the differential signal directly. To solve this problem, Mr. K. Pal issued the new application circuit in 1989. This new application circuit is added a differential amplifier to terminal Y of CCII with voltage gain being unity . Mr. K Pal called it “ DVCCII”, which had three input terminals and two output terminals. In 1997, Mr. Soliman and Mr. Elwan proposed the improving circuit of DVCCII. They called it “ Differential Voltage Current Conveyor, DVCC”. This paper proposed a new sinusoidal oscillator employing a plus-type differential voltage current conveyor (DVCC+). Comparing with previous issued paper in regards to this topic, this paper provided a new design with less components, one single output DVCC+ plus two resistors and two capacitors. It’s easier to achieve in the integrated circuit because all the capacitors are grounded. This paper uses UMC’s 0.5um process parameters to design DVCC+ and uses HSpice to simulate. Passive elements are chosen as below, RX=5.1K Ω；R1＝10KΩ；CX=8nF；C1=2nF. The oscillation frequency is 7.879KHz. According to the simulation by Hspice, this new oscillator has good performance for the temperature and voltage operation deviations.

並列關鍵字

oscillator ； differential voltage current conveyor

參考文獻

[1] B. Wilson, “Recent developments in current conveyors and current

[2] C. L. Hou, Y. T. Chen, and C. C. Huang, “The Oscillator Using a single DVCC. “ Tamkang Journal of Science and Engineering, 6(3), pp.183-187, 2003.

[3] B. Wilson, “Constant bandwidth voltage amplification using current conveyor,” International Journal of Electronics, Vol.65, No.5, pp.938-988, 1998.

[6] Svoboda, J.A.” Comparison of RC OP-Amp. And RC current conveyor filter”, Int. J. ELECTION. , 76 (4), pp.615-626, 1994.

[8] A. S. Sedra and K. C. Smith , “A second-generation current conveyor

國際替代計量

差動電壓電流傳輸器組成的振盪器

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