DC small current constant-current source and calibration method thereof

Abstract

The invention provides a DC small current constant-current source and a method for adjusting the constant-current source and aims at solving the problem of the noise of the output current caused by the noise of an amplifier in a feedback circuit of the existing DC small current source. The DC small current constant-current source comprises a voltage source, a differential amplification circuit, aV / I conversion circuit, a current output terminal and a feedback circuit; the voltage source is connected in series with the differential amplification circuit and outputs voltage to the differentialamplification circuit; the differential amplification circuit is connected in series with the V / I conversion circuit; the V / I conversion circuit generates the current and outputs the current by the current output terminal; the feedback circuit comprises a sampling circuit and a filter circuit which are connected in series; after sampling at the output current terminal of the V / I conversion circuit, the sampling circuit outputs the voltage signal which is fed back and filtrated by the filter circuit to the input terminal of the differential amplification circuit. Meanwhile, the output voltage of a feedback branch is taken as the following output voltage of the current output terminal. The invention can provide the DC small current with high precision.

Description

technical field [0001] The invention relates to a current source, in particular to a current source capable of outputting a small DC current. Background technique [0002] After years of development of DC small current sources, various types of products have been widely used. The most widely used types are resistive, capacitive and ionization. The resistive DC small current source is composed of a voltage source and a high-value resistor in series, and a definite DC small current can be obtained when the resistance of the voltage source and the high-value resistor are known. This kind of resistive DC small current source has a simple structure, but there are the following problems: that is, the load in the circuit where the DC small current source is applied cannot be determined, and the uncertainty of the load has a relatively large impact on the output current value of the small current source, especially Especially in the working environment with high precision requirem...

AI Technical Summary

Problems solved by technology

[0007] In order to solve the problem of output current noise caused by amplifier noise in the feedback circuit existing in the existing DC small current source, the present invention provides a DC small current constant current source with a new circuit structure, which can not only output current accurately and stably, but also Significantly reduces current noise, making it suitable for high-precision circuits

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