1、 I 摘 要 本设计以 AT89S52 单片机为核心控制芯片，实现数控直流电源功能的方案。设计 采用 8 位精度的 DA 转换器 DAC0832、三端可调稳压器 LM350 和一个 UA741 运算放大器 构成稳压源，实现了输出电压范围为1.4V+9.9V，电压步进 0.1V 的数控稳压电源， 最大纹波只有 10mV，具有较高的精度与稳定性。另外该方案只采用了 5 个按键实现输 出电压的方便设定，具有设定值调整，微调（步进量 0.1） ，粗调（步进量 1）三种调 整功能，显示部分我们采用了三位一体的数码管来显示输出电压值。我们自行设计了 12V 和 5V 电源为系统供电。该电路的原理是通过 M
2、CU 控制 DA 的输出电压大小，通 过放大器放大，放大后的电压作为 LM350 的参考电压，真正的电压还是由电压模块 LM350 输出。利用 5 个按钮调整电压、并且通过共阴极三位一体 LED 显示输出的电压 值。 设计使用 3 三位一体数码管， 可以显示三位数， 一个小数位， 比如可以显示 5.90V， 采用动态扫描驱动方式。与传统的稳压电源相比具有操作方便，电源稳定性高以及其 输出电压大小采用数码显示的特点。 关键词：数控，步进，三端可调稳压器 II ABSTRACTABSTRACT The design is with the MCUAT89S52 for the core contr
3、ol chip,which carry out the project that the function of the number controls the direct current power supply.Designed with the precision of eight DA converter DAC0832, three-adjustable regulators LM350 and a UA741 Operational Amplifiers constitute Regulators source, the output voltage range of +1.4
4、V +9.9 V, 0.1V voltage step NC Regulators Power, it has with high precision and stability and only have the biggest ripple of 10 mV. Meanwhile, the program used only five keys to achieve the convenience of the output voltage setting ,with setting value adjustments. It has three kinds of adjust funct
5、ion,which can carry out micro-adjustment (Stepping volume 0.1)and the coarse adjustment (Stepping volume 1). The show part we have adopted a three-dimensional digital pipe to show the output voltage value. And we designed the 12V and 5V power supply system for electricity. The principle of that elec
6、tric circuit was that the output voltage size which passes the MCU to control DA, passing the amplifier amplification, and the voltage is the reference voltage of the LM350. And the real voltage is still the LM350 outputs are from the voltage mold piece. Making use of five buttons to adjustment voltages, and pass the total cathode Christian Trinity LED to display the outputs voltage .In this design I used 3 piece code tubes, which can show three position numbers, one of them is a fract
