A high-precision weak current source using operational amplifiers

作者:Lei Shengjie*; Wei Zhiyong
来源:International Journal of Electronics, 2012, 99(6): 761-775.
DOI:10.1080/00207217.2011.643499

摘要

A high-accuracy current source has been developed for the generation of very small currents (below 10 pA) based on operational amplifiers. Precision current sources have been built using op amps, resistors, constant voltage and standard resistance values to gain weak current output with V-I converter. A complete analysis of this current source with respect to its dynamic properties, its equivalent relative error and circuit design is given. The effects of stray impedances on the behaviour of the current source are taken into account and the techniques necessary to achieve an optimum stable performance, with respect to noise, the sensitivity, leakage currents, are applied. Experiments show that the micro-current source is stable and reliable; the output current range of circuit is 10 pA-1 mu A.

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