The Design Of Programmable High-accuracy Two-way Constant-current Source

Current source is a kind of integral equipment in electronic engineering orscience.Especially in electronic engineering, current source is necessary in measure,debugging, calibration and controllability.With the increasing of intricacy, it means alot to develop a programmable two-way current source with high accuracy.The full text is divided into the overall design description, the hardware circuitdesign, programming and testing of four parts.The overall design description shows the closed-loop control. In the end of thispart, I described the considerations of the sampling resistor to avoid possible errors.The hardware design part contains the MCU circuit design, AD/DA circuitdesign, current detection system and PCB design.The software design part contains driver program, the control logic and the mainprogram.In this paper, based on the current output range of programmable current sourceare widespread small or current output precision is not high and can’t achievebidirectional output, design and implements a wide range of high precision based onkelvin test bidirectional current source module. Used in the design of high precisiondevices and closed loop control mode to ensure the output precision, high precisionoperation amplifier is used V-I conversion, guarantee the precision of the output atthe same time increase the range of output.Test results show that the current sourceoutput range for8to8A, output current error is not more than plus or minus10ua,improves the output range and precision very well.