Disorder and calibration method suitable for SAR ADC with non-loop structure

Abstract

The invention discloses a disorder and calibration method suitable for an SAR ADC with a non-loop structure. The method comprises the following steps of carrying out foreground calibration on a reference comparator in an ADC, namely comparing a positive input end and a negative input end of the reference comparator, and increasing a voltage value according to a comparison result in order to compensate an offset; carrying out disorder operation on the comparator in each conversion cycle, and selecting one for comparing an MSB bit of the second conversion by adopting a pseudo random number sequence; and calibrating the comparator after the disorder operation, namely judging whether the current comparison cycle is an LSB bit comparison, if yes, comparing the output result of the reference comparator and the output result of the LSB bit comparator, and increasing calibration voltage input by the LSB bit comparator according to the comparison result. According to the method, the calibrationis carried out by comparing the output result of the LSB bit comparator after disorder with the output result of the fixed reference comparator, the additional time is not increased, and the convergence speed of a calibration algorithm is accelerated.

Description

technical field [0001] The invention relates to a random sequence and calibration method suitable for non-loop structure SAR ADC, belonging to the technical field of SAR ADC. Background technique [0002] High-speed and low-power analog-to-digital converters are widely used in the communication field. Traditional SAR ADCs are limited by their working principles, making it difficult to achieve high-speed performance. In recent years, with the continuous development of advanced technology, SAR ADC has benefited from its high degree of digitality, and its speed can be relatively high. Many studies have devoted themselves to greatly increasing the speed of SAR ADC through structural improvements. Among them, the non-loop structure uses a separate comparator to work in each comparison cycle, which greatly reduces the logic delay of the traditional loop structure and improves the conversion speed. However, the introduction of multiple comparators will cause the offset of the comp...

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, provide a disorder and calibration method suitable for non-loop structure SAR ADC, and solve the problem that the introduction of multiple comparators will cause comparator imbalance and Mismatch between, making the calibration of multiple comparators affected

Images