Variable weight subDAC correction method for high-precision successive approximation structure ADC

Abstract

The invention provides a variable weight subDAC correction method for a high-precision successive approximation structure ADC, and the method comprises the steps: starting an analog-digital converter for sampling, collecting and obtaining a conversion curve; segmenting the conversion curve according to the resolution of the analog-digital converter; presetting correction codes for offset error correction; respectively employing different correction codes for each segment to carry out the correction of offset errors. According to the invention, a segmented correction method is employed for achieving the linearization of the whole conversion curve, and different weight correction values are employed at different segments of the conversion curve, thereby achieving the linear correction of the whole conversion curve, achieving the comprehensive correction of various types of conversion errors, greatly reducing the matching errors, caused by the changes of an analog input voltage, of a device, and meeting the requirements of a wide-input high-precision analog-digital conversion circuit.

Description

technical field [0001] The invention relates to the field of electronics, in particular to a variable weight quantum DAC correction method of a high-precision successive approximation structure ADC. Background technique [0002] Successive approximation (SAR: Successive-Approximation-Register, successive approximation register) ADC is one of the commonly used ADC structure types, and has been widely used due to its advantages of simple structure, easy integration, and low power consumption. At present, with the improvement of the conversion accuracy of the successive approximation ADC, due to the deviation of the process, the corresponding conversion accuracy requirements can no longer be met, and it must be adjusted according to the actual situation of a single circuit. Since the design of high-precision ADC must rely on calibration technology, at present, there are two types of general calibration technology: one is analog calibration technology, which adjusts the relevant...

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Problems solved by technology

[0003] However, in the traditional fixed weight correction method, the correction value of each weight is fixed, the logic and timing operations are simple, and it can only correct the fixed matching error of the process, and the matching error caused by the device itself changing with the analog input voltage It is powerless, and it has been unable to meet the design requirements of the current wide-input high-precision analog-to-digital conversion circuit

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