PRECISION ANALOG TO DIGITAL AND DIGITAL TO ANALOG CONVERSION USING REFERENCE RECIRCULATING ALGORITHMIC ARCHITECTURES (CODEC, CYCLIC, SUCCESSIVE APPROXIMATION)

摘要

In recent years, complicated and powerful digital signal processors have been implemented as a single integrated circuit. Because of the advantage of noise immunity and process insensitivity in digital processing, there is a trend toward having more signal processing done in digital form instead of in analog form. However, a major obstacle in the transition to digital processing is the expensive high resolution analog to digital converter and the digital to analog converter required before and after the digital processing.;In this thesis, a new method of cyclic analog to digital (A/D) and digital to analog (D/A) conversion using switched capacitor techniques is described. By periodically modifying the reference voltage to compensate for the non-ideal signal transfer loop gain in alogorithmic converters, it is possible to realize analog-digital and digital-analog converters whose linearity is independent of component ratios and which occupy only small die area. These converters require only two moderate-gain MOS operational amplifiers, on comparator, and a few capacitors. Two test chips for A/D and D/A conversion were built. The test data shows that the experimental A/D performs as a monotonic 13 bit converter with maximum 1 LSB differential and 2 LSB integral non-linearity.