Circuit and method for eliminating leakage current of charge test circuit

Abstract

The invention relates to a circuit and method for eliminating leakage current of a charge test circuit. The circuit comprises an input protection circuit, an operational amplifier circuit, a feedback circuit, a proportional operation circuit and a digital-to-analog conversion circuit, the magnitude of the leakage current is calculated by sampling two times of charge quantity of a tested piece, so that a voltage value which should be compensated by the digital-to-analog conversion circuit is calculated; and the digital-to-analog conversion circuit is superposed with a compensation value to be output, and the offset voltage is offset, so that the leakage current is eliminated. According to the circuit and method for eliminating the leakage current of the charge test circuit, the voltage of the input end of the test circuit is changed by sampling the test value in real time, calculating the magnitude of the leakage current and adjusting the magnitude of the DAC, so that the leakage current generated by the input offset voltage and the input bias current of the operational amplifier is eliminated, test reaches a stable and accurate state; and the test precision and the test efficiency are ensured.

Description

Technical field: [0001] The invention relates to the technical field of electronic measurement, in particular to a circuit and a method for eliminating the leakage current of a charge test circuit, which can measure a stable, accurate and stable charge. Background technique: [0002] Now when testing the charge of components, the analysis finds that there are individual differences in the components in the circuit, and it is impossible to have a theoretical state like integrated operational amplifiers, so factors such as temperature drift of components and offset voltage of integrated operational amplifiers, etc., lead to There is a leakage current in the test circuit, and the test charge becomes smaller, and the test charge amount will decrease with the increase of the test time, which makes the test value deviate. [0003] Therefore, it is necessary to add a leakage current compensation circuit to the charge test circuit, and cooperate with the software algorithm to make t...

AI Technical Summary

Problems solved by technology

[0002] Now when testing the charge of components, the analysis finds that there are individual differences in the components in the circuit, and it is impossible to have a theoretical state like integrated operational amplifiers, so factors such as temperature drift of components and offset voltage of integrated operational amplifiers, etc., lead to There is a leakage current in the test circuit, the test charge becomes smaller, and the test charge will decrease with the increase of the test time, which makes the test value deviate

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