An Out-of-Sequence and Calibration Method for Non-Loop-Structured Sar ADC

Abstract

The invention discloses a disorder and calibration method applicable to a SAR ADC with a non-loop structure. According to the comparison result, the voltage value is increased to compensate for the offset; in each conversion cycle, the comparator is operated out of order, and a pseudo-random number sequence is used to select one to compare the MSB bit of the second conversion; for the comparator after the out-of-order operation Carry out calibration, including: judging whether the current comparison cycle is LSB bit comparison, and when judging as LSB bit comparison, comparing the output results of the reference comparator and LSB bit comparator, and increasing the calibration of the LSB bit comparator input according to the comparison result Voltage. The present invention calibrates by comparing the output results of the disordered LSB bit comparator and the fixed reference comparator, without adding extra time and speeding up the convergence speed of the calibration algorithm.

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

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