使用數位誤差平均技術之導管式類比數位轉換器

Digital Error-Averaging Technique for Pipelined Analog-to-Digital Converter

黃威仁(Wei-Jen Huang)

指導教授 ： 劉深淵

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.01014

摘要

比較型類比數位轉換器是目前速度最快的一種，然而在提高解析度的需求時，則需要增加大量的比較器，同時轉換器的消耗必v、晶片面積也因而增加。因此，導管型類比數位轉換器是目前比比較型類比數位轉換器更適合發展快速及高解析度的架構。但是，導管型架構的類比數位轉換器其準確度很容易受到內部電路特性的影響，精確度受限的因素有運算放大器與比較器的非理想補償電壓、運算放大器的直流開迴路電壓增益、運算放大器的非線性程度、製程中電容不匹配的發生等等，其中造成轉換器非線性誤差的原因以電容不匹配的影響較為主要。到目前為止，已有些人提出改善積分型非線性誤差的技術，這些方法有的使用額外的類比電路，也有使用校正電容技術來完成導管型類比數位轉換器。本論文提出一個數位誤差平均的技術來降低因電容不匹配所產生的誤差。
在此次研究當中，一個十二位元每秒五十百萬次並使用數位誤差平均技術的導管型類比數位轉換器，在0.35微米互補式金氧半導體製程已經被設計與實現，它每級利用兩次交換電容方式來取得因應電容不匹配的兩筆數據，在最終的移位及閂鎖電路之後，再做最後平均，此平均結果可改善積分型非線性誤差，增加效能。

關鍵字

類比數位轉換器

並列摘要

The pipeline architecture is more suitable for some applications with the requirement of high resolution than the flash analog-to-digital converter (ADC) architectures, due to its small size and low power consumption. However, the accuracy of a pipelined ADC architecture is susceptible to circuits imperfections, such as offset voltages, gain errors, non-linearity of operational trans-conductance amplifier (OTA) and capacitors mismatch and so on. The effect of circuit impairment is associated with each stage of a pipelined ADC architecture. The disadvantage of non-linearity still remains limited on component mismatch. To date, some techniques have been proposed for improving the INL. These techniques used some extra analog circuits or calibration circuits for the implementation of a pipelined ADC. In this thesis, we present a new digital error-averaging technique to reduce the mismatch effect due to the employed components.
In this research, a 12-bit 50MS/s pipelined ADC with a digital error-averaging technique has been designed and implemented with standard 0.35-µm double-poly four-metal CMOS process. This technique used two pass commutating feedback-capacitors at one sample input signal, and used digital circuits to average the twice data for improving the integral non-linearity of pipelined ADC.

並列關鍵字

analog-to-digital converter

參考文獻

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