零點三五毫微米互補式金氧半八位元分段式類比至數位轉換器之設計與分析

Abstract

近年來，液晶顯示器廣泛應用在個人電腦或手機上頭，其中重要關鍵元件為類比至數位轉換器。本文即探討各類型轉換器的應用範圍進而導入使用分段式類比至數位轉換器的目標，並分析此類型轉換器的主要問題以及如何加入數位電路以做錯誤修正。實際設計一個八位元的兩段式類比對數位轉換器，以所規劃的時序關係使其在三點三伏特工作電壓下能有每秒五千萬個取樣數。在此電路架構中不需用到高增益的運算放大器以及高準度的取樣保持電路，其主要電路元件為概略比較器以及細微比較器。以開關電容式反相器當成細微比較器的主體，並使用金氧半電晶體閘極電容當成偶合電容以節省元件面積。此類比至數位轉換器是以台灣積體電路公司零點三五微米製程技術設計，經過模擬驗證合乎八位元解析度與每秒五千萬個取樣數。並規劃測試環境以實施測試一般類比至數位轉換器的參數值，以佐證是否合乎原先設計目標進而探討改善空間。

Recently, the liquid crystal display (LCD) has been popularly used in notebook and mobile phone. The A/D converter is a component in the LCD monitor. This thesis introduces several types of A/D converter from the application point of view. Thus, the subranging A/D converter is analyzed for this research goal. The design goal of an 8-bits subranging A/D converter is 50MS/s at 3.3V using the proposed scheme of timing sequence. The architecture of the A/D converter is without OP amplifier and S/H circuit. The primary components of the A/D converter are the coarse comparators and the fine comparators. The switch-capacitor inverter is the main idea for the fine comparator, and thus the MOSFET capacitor is used for coupling capacitor to reduce the area. The A/D converter is designed with the TSMC 1P4M 0.35um process. In the simulation result, it can achieve a resolution of 8-bit and the speed of 50MS/s. The plan of test is for measuring the parameter of the A/D converter to prove the specifications and improve in future.