数控直流恒流源的设计

数控直流恒流源的设计

摘要

直流恒流源是提供稳定直流电流的电源装置，是科学实验和设备调试中的一种必备设备。本文介绍了采用AT89C51单片机为主控制器，通过键盘来设置直流恒流源的输出电流，并由数码管显示电流设定值的数控直流恒流源。本系统由单片机程控设定数字信号经过D/A转换器输出模拟量，再经过V/I转换电路的转换输出不同的电流。输出电流范围为10～100mA，电流设置步进为1mA，输出电流调整率≤2%。

本文主要分析了数控直流恒流源系统的设计需求，阐述了数控直流恒流源的软硬件的设计原则，介绍了数控直流恒流源各模块电路的功能及设计思路，完成了数控直流恒流源系统的全部设计，给出了完整的电路图和程序。本文设计的重点是单片机主控系统和D/A转换电路，设计的难点是高线性、高稳定度的电压/电流转换电路（V/I转换电路）。测试结果表明，本系统能满足需要高稳定度的小功率直流恒流源领域的应用要求。

关键词数控恒流源 V/I转换

ABSTRACT

Numerical control DC constant current source is to provide a stable DC power devices, and equipment for scientific experiments debugging necessary equipment. This paper instructed the numerical control DC constant current source which makes use of the AT89C51 version single chip microcontroller is the main controller in this system, while the set value and the real output current can be displayed by LED. In this system, the digitally programmable signal from Single Chip Micro controller is converted to analog value by D/A converter, and then transited by voltage/current converter circuit, so adjustable output different current. Output current range of 10~100mA, current set of 1mA step, the output current adjustment rate of less than 2%.

This paper analyzes the numerical control DC constant current source system design needs, expounded numerical-controlled DC constant current source of the hardware and software design principles, instructed the numerical-controlled DC constant current source circuit of the module function and design ideas, completed the numerical-controlled DC current source of all design, and the circuit is complete and procedures. This paper focuses on the design of the control system microcontroller and D/A Conversion Circuit, The difficulty in the design of high linearity, high stability of the voltage/current converter circuit (V/I Conversion Circuit). The test results have showed that it can be applied in need areas of constant current source with high stability and low power.

KEY WORDS numerical control constant current source V/I convert

目录

前言 (1)

第1章系统总体设计 (2)

1.1 系统设计任务与要求 (2)

1.1.1 系统设计任务 (2)

1.1.2 系统设计要求 (2)

1.2 重点研究内容与实现方法 (2)

1.2.1 重点研究内容 (2)

1.2.2 实现途径及方法 (3)

1.3 系统总体方案设计 (3)

1.3.1 主控模块 (3)

1.3.2 键盘与显示模块 (4)

1.3.3 恒流源模块 (4)

1.3.4 存储器扩展模块 (4)

1.3.5 电源模块 (5)

1.3.6 系统原理框图 (5)

第2章系统硬件各功能模块的设计 (6)

2.1 主控模块的设计 (6)

2.1.1 AT89C51单片机简介 (6)

2.1.2 D/A转换电路的设计 (7)

2.1.3 恒流源电路的设计 (9)

2.1.4 数据存储器的扩展 (10)

2.1.5 系统资源分配 (11)

2.2 人机接口的设计 (12)

2.2.1 键盘的设计 (12)

2.2.2 显示电路的设计 (14)

2.3 系统抗干扰设计 (15)