文档介绍：基于AT89C51的数控直流电流源设计
摘要
随着单片机技术的快速发展,基于单片机的微处器的应用越来越广泛。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,并可由数码管显示实际输出电流值和电流设定值。本系统由单片机程控输出数字信号,经过D/A转换器(ADS7841)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。控制部分选用单片机与专用的PWM调制芯片相结合的方式来控制MOSFET开关管的导通。其输出电流的大小通过隔离型电流传感器转换成对应的模拟信号。实际测试结果表明,本系统实际应用于需要高稳定度小功率恒流源的领域。
关键词压控直流源,PWM调制芯片,闭环控制
Abstract
With the rapid development of single-chip technology, based on the single-chip micro-Department's application of more and more widely. AT89S52-based single-chip controller, through the keyboard to set the DC power supply output current, set the level of stepping up to 1mA, and the digital display from the actual output current value and current settings. The system consists of single-chip programmable digital signal output through D / A converter (ADS7841) analog output, and then zoom through the isolation amplifier to control the output power of the base tube, with the base of power changes in voltage output different currents. Control of some selected single-chip PWM modulation and the exclusive use of bination of chips to control the MOSFET turn-on switch. The size of its output current through the isolation-type current sensor into a corresponding analog signal. The actual test results indicate that this system applies to the actual needs of low-power high stability constant current source of the field.
Key Words DC voltage source, PWM modulation chips, closed-loop control
目录
摘要 I
Abstract II
目录 III
1 引言 1
1
国内外研究现状 1
AT89C51单片机简介 1
、目标与方法 2
2
3
本文的目的和意义 4
2数控直流电流源设计构思 5
5
开关管的选择 5
PWM芯片的选择 5
电流传感器的选择 6
A/D和D/A芯片的选择 8
控制器芯片的选择 8
人机界面 8
辅助电源选择 9
3数控直流电流源的子模块设计 10
10
PWM调制波与MOSFET的驱动电路设计 11
斩波电路与滤波稳流电路设计 11
14
单片机最小系统设计 15
A/D、D/A 的转换电路设计 15
键盘和显示电路及辅助电源电路设计 17
系统误差分析 17
系统的热设计与电磁兼容设计 18