• 沒有找到結果。

經過量測及分析結果後,有下列幾點建議提供作為未來可改進之方向:

 因 為 整 體 電 路 架 構 複 雜 又 有 些 演 算 法 是 由 FPGA 實 現 , 且因 為 運 用 到 Correlation-based 的 概 念 , 模 擬 上 需 要 的 資 料 量 過 於 龐 大 , 僅 能 做 Behavior-simulation 而無法進行電路的 post-simulation,故可在各級之間加入測 試電路(Design-for-Testability,DfT)單獨量測各級,在除錯(Debug)時才 能更精確掌握問題發生之原因。

 設法解決當 Backend ADC 或 Sub_ADC 存在 Offset 時,可能會對後續 Estimation 和 Calibration 演算法產生的影響。

 可將導入之隨機校正訊號±N , Nd 1 ± d 2的振幅縮小,則當 Sub_ADC 中的比較器 產生偏移誤差或是增益級產生增益誤差時,增加 MDAC 可容許錯誤範圍,不 過相對來說缺點是這樣會使校正參數的收斂時間拉長。

 雖然此論文所提的校正方法可用在多級校正級,但設計的 12-bit Pipelined ADC 前二級均為校正級,使得架構複雜度大為提升,故初步階段可考慮僅先使用 單一級校正級,確保電路可校正成功後再往下發展。

 為追求低功率消耗的設計本論文 MDAC 採用 Open-Loop 的架構設計,亦可考 慮以低開迴路增益之 Close-Loop 架構實現,再評估二種架構的功率消耗和穩 定度之表現。

 圖 5-3 Bootstrapped Switch 電路中電晶體 M0的基板(Body),可藉由提供的

Deep N-well 製程技術,將基板電壓接至源極(Source)端以消除基板效應(Body

Effect),使開關具有更為線性的導通阻值進而提升整體 S/H 電路效能,圖 7-1

為消除 Body Effect 後 S/H 電路 pre-simulation 的頻譜分析結果,ENOB 可由原 來的 11.8 bits 提升至 12.5 bits。

Power Spectral Density (dBFS/bin)

Power Spectrum 4096 points FFT

Fi = 10MHz , Fs = 100MHz

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