用於遞迴式類比數位轉換器之數位背景校正技術

Digital Background Calibration Techniques for Cyclic Analog-to-Digital Converters

周士欽(Shih-Chin Chou)

指導教授 ： 劉深淵

國立臺灣大學/電機資訊學院/電機工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.10261

摘要

隨著數位訊號處理技術的快速發展，支援的軟體也日益便利，越來越多的類比系統漸漸被數位取代，數位訊號有著比類比訊號容易處理優點，將複雜的類比電路用數位取代，所需的成本也更低，因此日常生活電子商品之數位化正形成一種新的趨勢。本論文即採用數位訊號處理演算法，改善遞迴式類比數位轉換器效能，此類轉換器其準確度很容易受到內部電路特性的影響，包含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、製程中電容不匹配等等因素，其中造成轉換器非線性誤差的原因以電容不匹配和比較器偏移誤差的影響較為主要。

本論文以運用數位背景式校正技術為主軸，改善交換電容CMOS遞迴式類比數位轉換器地解析度到達十位元，在台積電0.35um雙氧化層以及四層金屬的製程已經被設計與實現，晶片面積為1800um × 1800um，使用3V單電壓，功率消耗約240mW，並使用FPGA做數位背景校正來估計類比數位轉換器真實的增益值，用來降低因為電容不匹配和比較器偏移所造成的誤差，演算法校正展現降低製程影響之極佳能力。

關鍵字

遞迴式類比數位轉換器 ； 數位校正 ； 數位演算法

並列摘要

The rapid growth of DSP techniques makes it easier to design the digital system. More and more analog circuits have been replaced by digital systems. Hence, this thesis is targeted at incorporating DSP technique into cyclic ADC to improve circuit performance. The accuracy of a cyclic ADC architecture is susceptible to circuits imperfections, such as offset voltages, gain errors, non-linearity of operational trans-conductance amplifier (OTA), capacitors mismatch and comparator offset and so on.

This thesis presents a 10-bit switched-capacitor cyclic ADC with a digital background calibration technique. The chip has been implemented with standard 0.35-µm double-poly four-metal CMOS process and occupies an area of 1800 um × 1800 um , and the power consumption is 240mW with a single 3.3V supply. The digital algorithm which can estimate the gain of ADC to reduce the capacitors mismatch and comparator offset has been demonstrated with better performance and implemented by FPGA.

並列關鍵字

cyclic adc ； digital calibration

參考文獻

[1.1] B. Razavi, “Design of Analog CMOS Integrated Circuits,” McGraw-Hill Publishers, 2001.

[1.2] R. L. Geiger, P. E. Allen, N. R. Strader, “VLSI design techniques for analog and digital circuits,” McGraw-Hill Publishers, 1990.

[1.3] P. E. Allen, and D. R. Holberg, “CMOS Analog Circuit Design,” Oxford University Press, 2002.

[2.2] B. Razavi, “Principles of Data Conversion system Design,” A John Wiley & Sons, Inc., 1995.

[2.4] A. Moscovici, “High Speed A/D Converters,” Kluwer Academic Publishers, 2001.