低成本高效能電流比較器於記憶體、中頻數位轉換與 電流模式邏輯應用

Cost Effective Current Comparator for Memory, Intermediate Frequency to Digital Conversion and Current Mode Logic Applications

張維麟(Wei-Lin Chang)

指導教授 ： 蔡澈雄

共同指導教授 ： 陳朝烈(Chao-Lieh Chen)

崑山科技大學/工程學院/電子工程研究所/碩士(2009年)

摘要

以威爾森電流鏡為基礎所設計之威爾森電流比較器，特性上具有高靈敏的切換運作，以威爾森電流比較器為基礎設計成電流感應放大器、資料轉換器、電流模式邏輯等新型電路架構，簡化傳統電路設計上的複雜度，達到減少功率損耗之目標。威爾森電流比較器是利用電流鏡的鏡射特性構成自我偏壓型態電路，威爾森電流鏡本身具有相當高的阻抗可提高電流穩定效果，基於低壓與穩定的優點可產生具有高靈敏感應、快速電流切換的運作，透過適當的MOS長寬比設計可將運算電流控制在最小，達到最低功率損耗。我們以感應放大器、資料轉換器與電流模式邏輯電路作為驗證威爾森電流比較器的電路性能，在TSMC 0.18um製程的表現，電流模式感應放大器的sensing time為0.2ns，中頻/數位轉換器的功率消耗約為2.2mW，威爾森電流模式邏輯，透過HSPICE所測得的功率損耗並不會隨著頻率提高而有大幅度的改變。驗證了威爾森電流比較器的結構設計具有高度前瞻性的優異性能，以現今VLSI設計所強調的降低功率損耗，威爾森電流比較器架構的提出在系統應用的技術上具有相當程度的突破。

關鍵字

威爾森電流鏡 ； 電流模式邏輯 ； 感應放大器 ； 中頻/數位轉換器

並列摘要

We propose a current comparator based on differential Wilson current mirrors. The Wilson Current Comparator (WCC) possesses high sensibility and performs high speed switching operations. We utilize the WCC to implement novel circuits such as current-mode sense amplifier, data converter, and current-mode logic gates. Therefore, utilizing WCC simplifies traditional circuit designs and reduces power consumptions. The WCC comprises differential current mirrors where tail current is realized by the self-biased structure of the Wilson current mirror. Since Wilson current mirror advantages very high output-resistance that stabilize output currents, the differential WCC highly sense input and perform high-speed switching operation. The current required to perform the comparing function can be easily adjusted by adequate MOS aspect ratios and in this way the power consumption is easily optimized. We illustrate sense amplifier, data converter, and current-mode logic circuits to verify WCC performance. Fabricated in 0.18?慆, the sense amplifier has sensing time 0.2 ns, the direct intermediate-frequency (IF) to digital converter only consumes 2.2mW, and the current-mode logic circuits are also proved having nearly constant power consumption with respect to frequency increase of clock signals such that this type of current mode logic circuits have the least power-delay product (PDP) performance especially for complex logic functions. According to the above examples, we’ve verified that circuits exploiting WCC structure are superior to state-of-the-art VLSI circuits utilizing conventional comparators.

並列關鍵字

Wilson current mirror ； current mode logic ； sense amplifier ； intermediate frequency to digital converter

參考文獻

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