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
2、电。该 电路的原理是通过 MCU 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 ABSTRACT The design is with the MCUAT89S52 for the
3、 core control 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 ran
4、ge of +1.4 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 a
5、djust function,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 o
6、f that electric 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 adju
7、stment 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 fraction position. for example ,it can show a 5.90 Vs. In this design I adopt the scan to drive way is dynamic state sweep. With traditional steady press power supply to compare to have an operation convenience, the power supply stability high characteristics, its exportation electric voltage size adoption figures show. Keywords: Numerical Control, Stepping,Three-adjustable regulators
