Low leakage current resetting device applied to capacitive integrating weak current measuring circuit

Abstract

The invention belongs to the technical field of weak current measurement, and particularly relates to a low leakage current resetting device applied to a capacitive integrating weak current measuringcircuit. The resetting device is connected with a capacitance integrating weak current measuring circuit (2) used for measuring weak current to be measured (1). The resetting device comprises a resetcurrent circuit (3), a multiplexer (4), a D / A converter (5), a voltage follower (6) and a logic control unit (7). The voltage follower (6) can copy the voltage of the weak current to be measured (1) as the turn-off voltage of the reset current circuit (3). The D / A converter (5) can provide turn-on voltage with adjustable polarity and magnitude for the reset current circuit (3). The resetting device further comprises a logic control unit (7) which controls the multiplexer (4) to select to output turn-off voltage or turn-on voltage, and controls the polarity and magnitude of the turn-on voltageoutput by the D / A converter (5). According to the invention, the measurement lower limit and the minimum resolution of the capacitive integrating weak current measuring circuit system can be greatly improved.

Description

technical field [0001] The invention belongs to the technical field of weak current measurement, and in particular relates to a low-leakage current reset device used in a capacitance integral type weak current measurement circuit. Background technique [0002] Generally nA(10 -9 The current below the magnitude of A) is called weak current. In scientific research work in the fields of radiation detection, electrochemistry, and new materials, it is often necessary to measure weak currents. The difficulty of weak current measurement is not only that the amplitude of the signal to be measured is very small, but also because it is extremely susceptible to various types of interference, and sometimes it is even overwhelmed by interference noise. The type of interference source is not only electronic noise, but also electric field, magnetic field and electromagnetic field, and even the triboelectric effect caused by mechanical vibration, the piezoelectric effect caused by externa...

AI Technical Summary

Problems solved by technology

[0006] Aiming at the large leakage current of the current integral weak current reset device, which seriously affects the lower limit of circuit measurement and the minimum resolution capability, the present invention develops a low leakage current reset device whose leakage current is less than 1fA (10 - 15 A), and can achieve adjustable output bipolar reset current, thereby greatly reducing the impact of the low leakage current resetter on the measurement lower limit and minimum resolution of the weak current measurement system, and greatly improving the performance indicators of the weak current measurement system

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