Calibration conversion method of digital-to-analog converter

Abstract

A calibration conversion method of a digital-to-analog converter relates to an integrated circuit technology, and comprises the following steps of: A, dividing a conversion circuit into a high-order section and a low-order section according to a digital signal bit, and assigning the bit number of the high-order section to m; assigning the digits of the high-order section to n; b, conducting low-level section conversion; c, conducting high-level section conversion; d, conducting high-position section conversion and low-position section conversion superposition; wherein the step C comprises the steps of repeatedly folding each high-level current source in half to obtain a final equivalent current source and a final calibration current source, recording a corresponding relation between each level of calibration current source and the contained high-level current source as a high-level DAC decoding scheme, and controlling an access switch from each high-level current source to an output line according to the scheme. The precision of the DAC is improved by fundamentally improving the matching precision of the matching device, a calibration DAC is not used, and the limitation of the matching precision of the device in the process is avoided.

Description

technical field [0001] The present invention relates to integrated circuit technology. Background technique [0002] DAC is widely used in various signal processing systems and analog-to-digital converters, and the system has higher and higher requirements for the accuracy of digital-to-analog converters. The realization of high-precision DAC also has higher requirements for device matching of digital-to-analog converters. At present, there is a limit to device matching in the CMOS process, and it is difficult for us to realize a higher-precision digital-to-analog converter simply by relying on the existing process. Therefore, in order to achieve higher conversion accuracy, some other methods must be adopted. Calibration is one of the more commonly used methods. The basic idea is to add a calibration DAC, such as figure 1 . The calibration DAC is realized by analog resistance, and there is also a problem of accuracy. If the required accuracy is high, the accuracy requirem...

AI Technical Summary

Problems solved by technology

Due to the limitation of device matching, the output voltage of the main DAC deviates from the output voltage of the ideal DAC

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