基于单片机的数控直流电流源的研制

Development of digitally-controlled DC current source based on single-chip microcomputer

目前所使用的直流可调电流源中,大多为旋钮开关调节电流,调节精度不高,而且经常跳变,使用麻烦。系统采用STC89C52为主控芯片,通过键盘改变或设定数字量,经D/A转换后产生相应的模拟电压Vo,此电压加到由运算放大器OP07组成的恒流源电路,输出相应的电流Io。利用本数控电源,可以实现步进为1 mA,输出电流范围20～2 000 mA,输出直流电压≤10 V,纹波电流≤1 mA。经测试,该系统稳定性好、精度较高、操作简单、人机界面友好,具有较高的实用性。

In the currently-used adjustable DC current source, the rotary switch is adopted to execute the current adjust- ment, but its regulation accuracy is not high, hopping occurs quite often, and its application is not convenient. STC89C52 is taken as a master chip in the system. The digital quantity is changed or set trough the keyboard. The corresponding analog voltage Vo is generated after D / A convertion, and imposed on the constant current source circuit composed of operational amplifier OP07 to output the corresponding current Io. With the digitally-controlled DC current source the system can achieve stepping 1 mA, output current range of 20-2 000 mA, output DC voltage≤10 V, ripple current≤ 1 mA. The testing that the system has high stability, high precision, simple operation, friendly interface and high practicality.