一种高精度压控电流源电路的设计与实现OA

This paper introduces the working principle of a voltage-controlled current source circuit,which is an improved version of the traditional Howland current source circuit.It employs a differential operational amplifier(op-amp)circuit structure to construct a volt-age-to-current conversion circuit.By using an FPGA to control the DAC output to generate different voltages,the circuit achieves cur-rent output ranging from 4 mA to 24 mA.The paper analyzes the impact of factors such as the op-amp,DAC,and resistor network on current output accuracy,providing guidance for component selection and circuit design.A compensation method using linear fitting is proposed,effectively improving current output accuracy.The constant current source circuit built using the SGM8249 operational ampli-fier was tested under temperature conditions ranging from-30℃to 70℃.Within the current output range of 4 mA to 24 mA,the maximum error did not exceed 0.03 mA,and the relative full-scale error was less than 0.15%,meeting the requirement of current out-put accuracy less than 0.3%in actual engineering applications.