Double passage differential anti-jamming current amplification circuit

Abstract

The invention relates to a differential anti-jamming current amplifying circuit with two channels, wherein a first and a second input ends of an electric current-voltage convertor are used as a first and a second input ends of the invention, and reference voltage ends of the first and the second input ends are used as a first and a second reference input ends, the output ends of the first and the second electric current-voltage convertors are respectively connected with positive input ends of a first and a second differential amplifiers, the first and the second reference input ends are respectively connected with negative input ends of the first and the second differential amplifiers, the output ends of the first and the second differential amplifiers are respectively connected with a positive-negative input end or a negative-positive input end of a secondary differential amplifier, and the output end of the secondary differential amplifier is the output end of the invention. The invention successfully measures weak signal of pien grade under the condition without a screen, measuring signal-to-noise ratio can be further improved under the condition with the screen, and non-electric common mode interference signal of vibration, thermal drift and the like can be inhibited.

Description

technical field [0001] The invention relates to a current amplifying circuit, in particular to a dual-channel differential anti-interference current amplifying circuit suitable for weak current measurement. Background technique [0002] Many important electrical (such as tunneling current of scanning tunneling microscope, electrocardiogram, brain wave, etc.) or non-electrical (light, sound, pressure and PH value, etc.) signal measurements are finally obtained by converting them into current measurements by circuits or sensors High measurement accuracy. Therefore, the measurement of current, especially the accurate measurement of weak current is becoming more and more critical. Existing weak current measurement technologies mainly include: transimpedance amplifier circuit, integration circuit, switched integration circuit, double channel cross-correlation amplification technology, etc. These technologies have a common disadvantage: better shielding devices must be used to p...

AI Technical Summary

Problems solved by technology

These technologies have a common disadvantage: better shielding devices must be used to prevent various external interference signals (such as 50HZ power supply line interference, mobile phone, radio signals, etc.) The current measurement signal is amplified by the measurement circuit together with it, resulting in a decrease in the measurement signal-to-noise ratio

This makes it difficult to obtain high measurement accuracy for many field measurements that are inconvenient to use shielding devices

Even for measurements where shielding is used, it is often not possible to completely shield interfering signals, which also does not improve the signal-to-noise ratio of the measurement circuit to its highest possible value

In addition, other non-electrical disturbances such as thermal drift and vibration noise will also have a significant impact on weak current measurements

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