数控直流恒流源的设计与制作摘 要：本系统以直流电流源为核心，AT89S52 单片机为主控制器，通过键盘来设置直流电源的输出电流，设置步进等级可达 1mA，并可由数码管显示电流设定 值和实际输出电流值。本系统由单片机程控设定数字信号，经过 D/A 转换器（AD7543）输出模拟量，再经过运算放大器隔离放大，控制输出功率管的基极， 随着功率管基极电压的变化而输出不同的电流。单片机系统还兼顾对恒流源进行实时监控，输出电流经过电流/电压转换后，通过 A/D 转换芯片，实时把模拟量转 化为数据量，再经单片机分析处理，通过数字量形式的反馈环节，使电流更加稳定，这样构成稳定的压控电流源。实际测试结果表明，本系统能有效应用于需要高稳 定度的小功率恒流源的领域。关键词：压控恒流源 智能化电源 闭环控制The Digital Controlled Direct Current SourceAbstract: In this system the DC source is center and 89S52 version single chip microcomputer (SCM) is main controller, output current of DC power can be set by a keyboard which step level reaches 1mA, while the set value and the real output current can be displayed by LED. In the system, the digitally programmable signal from SCM is converted to analog value by DAC (AD7543), then the analog value which is isolated and amplified by operational amplifiers, is sent to the base electrode of power transistor, so an adjustable output current can be available with the base electrode voltage of power transistor. On the other hand, The constant current source can be monitored by the SCM system real-timely, its work process is that output current is converted voltage, then its analog value is converted to digital value by ADC, finally the digital value as a feedback loop is processed by SCM so that output current is more stable, so a stable voltage-controlled constant current power is designed. The test results have showed that it can be applied in need areas of constant current source w...
