简易数字控制恒流源系统的设计和开发

Design and Development of a Simple Digital Control Constant-current Source System

设计了一种以单片机C8051F020为控制核心的简易数控恒流源系统,实现了电流从-2A到2A数字控制可调的直流恒流系统。系统电源部分采用大功率变压器供电,采用多级电容、π网络滤除纹波干扰;电源输出部分采用三端稳压芯片进行稳压,并且利用大功率达林顿管进行扩流以满足后级功率需求。恒流源部分采用多个精密运算放大器OP07构成闭环反馈控制形式,从而提高控制精度。受控部分采用达林顿管进行扩流和精确设定输出电流。电流测量部分采用康锰铜电阻丝作为精密取样电阻,而不受外界温度变化的影响;系统的显示部分采用128×64点阵式液晶显示屏实时显示设定电流值和实测电流值。数控恒流源具有控制界面直观、简洁的特点,具有良好的人机交互性能。

The paper designs a simple constant-current source based on SCM C8051F020 as a control core, and realizes a digital control adjustable DC constant-current system within the current range from--2A to 2A. The power part uses high power transformer for power supply, uses multilevel capacitance and a network to eliminate ripple interference. The power output part uses three-voltage chip for stabilizing voltage, and make use of high power Dalindon tube to enlarge current to meet the demand level after expanding power flow. The constant-current source part uses multiple precision operational amplifiers OP07 to constitute a closed-loop feedback control form, so as to improve the control precision, and the controlled part adopts Dalindon tube to enlarge current and precisely set output current. The current measurement part uses kang-manganese bronze resistance wire as the precise sampling resistance, free from the effect of ambient temperature. The display part uses 128 x 64 dot-matrix LCD for real-time display the setting current value and measured value. The digital control constant-current source features ocular and simple control interface, and good human-computer interaction.