A Correction Method of Differential AD Converter Circuit with Single-End Input

Abstract

The invention relates to a correction method for a single-end input differential AD converter circuit, which is used for eliminating the conversion error caused by the single-end-to-differential circuit parameter deviation at the input end of the circuit. In the single-end input data acquisition system using a differential A / D converter, the front-end single-end input differential output conversion circuit has a deviation in the resistance value of the resistance, which affects the conversion accuracy. On the basis of the calculation algorithm of the conventional sampling voltage value, the present invention introduces the resistance value with resistance value deviation as a parameter for calculating the sampling voltage value, obtains a correction algorithm for correcting the conventional calculation sampling voltage value algorithm, and eliminates the resistance value of the resistance value The impact of the deviation on the accuracy of the calculation of the sampling voltage value, and the accuracy consistency of the data acquisition system is guaranteed.

Description

technical field [0001] The invention belongs to the fields of electronic technology and computer technology, and in particular relates to a single-end input differential AD converter circuit correction method. Background technique [0002] In data acquisition, in order to suppress common mode interference, a differential A / D converter is often used for data sampling. The differential A / D converter requires the input signal to be a pair of differential signals. When the input signal is a single-ended signal, it is necessary to use a single-ended to differential circuit to convert the single-ended signal into a differential signal, and then input it into the differential A / D converter. Perform data conversion. After the differential A / D converter obtains the conversion result, it sends the result to the microprocessor for data processing, and the microprocessor restores the A / D conversion result to the input sampling voltage value through operation for subsequent processing. ...

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Problems solved by technology

[0021] For example, in a single-ended input data acquisition system using a differential AD single converter with an input range of 0-2Vref (Vref is the reference voltage), Vref is 5V, Vin input range is 0-10V, and Vin-Vref has a maximum value of 5V, when the error caused by the inconsistent resistance of R1 and Rf is required to be within 0.6mV, the relative error between R1 and Rf must be within 0.00012, which requires too high precision and consistency between R1 and Rf, and it is difficult to achieve in engineering. Not conducive to mass production

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