Analog to digital converter and method for evaluating capacitor weighting of digital-to-analog converter thereof

摘要

A method for evaluating capacitor weighting of an analog-to-digital (ADC) is provided. An equivalent weighting value of each composed capacitor in each sub-capacitor-array may be obtained by adding the switch device to the ADC which enables each sub-capacitor-array in a digital-to-analog (DAC) to be measured by each other. The ADC can calculate and then obtain a correct digital output by using the calibrated equivalent weighting and successive approximation result of each input signal.

主权项

1. A method for evaluating capacitor weighting of a digital-to-analog converter comprising:
selecting at least one of capacitor groups as a target group, and selecting at least one of the capacitor groups other than the target group as a reference group; using the reference group to measure a weighting code of each of the composed capacitors in the target group, and calculating a group weighting value of each of the composed capacitors in the target group according to the weighting code; selecting at least one of the capacitor groups not serving as the target group as a new target group, and selecting at least one of the capacitor groups other than the new target group as a new reference group; using the new reference group to measure the weighting code of each of the composed capacitors in the new target group, and calculating the group weighting value of each of the composed capacitors in the new target group according to the weighting code; repeating the aforementioned two steps until the group weighting values of all the composed capacitors in the digital-to-analog converter are obtained; and obtaining an equivalent weighting value of each of the composed capacitors according to the weighting code and the group weighting value of each of the composed capacitors in each of the capacitor groups.