Method for correcting single-ended input differential AD converter circuit

Abstract

The invention relates to a method for correcting a single-ended input differential AD converter circuit. The method is used for eliminating conversion errors caused by the single-ended to differential circuit parameter deviation of the input end of the circuit. In a single-ended input data acquisition system of the differential AD converter circuit, the conversion accuracy of a single-ended input and differential output converting circuit is affected by the resistance derivation of a resistor. According to the method for correcting the single-ended input differential AD converter circuit, the resistor resistance having the resistance deviation is introduced as a parameter for calculating the sampled voltage value on the basis of a conventional sampled voltage value computing algorithm and a correction algorithm for correcting the conventional sampled voltage value computing algorithm is obtained, and therefore, the influence of the resistor resistance deviation on the accuracy of sampled voltage value computation is eliminated, 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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