基于Wilson电流镜的精密压控电流源

将正负Wilson电流镜组合在一起,读取由运算放大器构成的电压跟随器的电源引线电流,得到高精度的压控电流源。通过仿真手段研究互补Wilson电流镜组合的电流跟随特性;用通用集成运算放大器和分立BJT(bipolar junction transistors)构成实验测试电路,给出精度、输出阻抗以及频率响应特性的实验测试结果。电路的带宽大大优于运算放大器的单位增益带宽积,体现了电流模电路的优势。当采用CB(complementary bipolar)工艺实现单片集成时,电路的性能更好。还给出了电路的几种改进方案,实验证明,方案是可行的。

Precision Voltage Controlled Current Source Based on Wilson Current Mirrors

Via the combination of positive and negative Wilson current mirrors,the current flowing into power terminal of voltage follower composed of operational amplifier can be gotten.Then the high-precision voltage controlled current source can be obtained.The characteristic of current following caused by the combination of complementary Wilson current mirrors was studied through simulation.With the experimental test circuit consists of a general integrated operational amplifier and discrete BJT(bipolar junction transistors),the experimental results of the precision of voltage controlled current source and the characteristic of frequency response were given.Circuit bandwidth is much better than the unit gain bandwidth of operational amplifier,which shows the dominances of current-mode circuit.when using CB(complementary bipolar)process to implement monolithic integration,the circuit’s properties will be better.Several improvement programs about circuit have been given.The experiments proved that the programs are practical.