摘要:社会在不断进步，技术也不断发展，电子产品日益增多，电子产品的电源的稳定性、精度等要求越来越高，而且其中很大一部分为恒流源，而传统的模拟恒流源，由于模拟电路的复杂性，越来越难满足高稳定性的应用场合。如今，单片机技术不断发展，日益成熟，其稳定性也不断提高，价格不断下降，A/D元件不断普及，使得单片机控制的电源成为可能。为此，结合单片机技术和V/I变换电路，采用反馈调整控制方案来设计制作了单片机控制的高精度脉冲恒流源。利用一种基于低压差（LDO）线性稳压器芯片NCP5662、单片机STC89C52、A/D 转换器、运算放大器等器件，通过控制开关二极管导通和关断的原理，达到了脉冲输出的目的，并提出了一种控制脉冲的简单方法。该电流源的电源电压为5V，脉冲上升时间小于3us，下降时间小于1us，脉冲宽度和频率独立可调，电源稳定、可靠。10423
关键词: 脉冲恒流；A/D；NCP5662；单片机
The design and the Implementation of High-precision pulse constant current source controlled by SCM
Abstract：Society and technology continues to evolve. The electronic products become more and more. Electronics power supply stability, accuracy become increasingly demanding. And a large part of the power is a constant current source. The traditional analogue constant-current source, since the analog circuit complexity, increasingly difficult to meet high stability applications. Nowadays SCM technology continues to evolve. The SCM technology become more sophisticated. And its stability is also rising. The price is also falling .A / D component growing popularity. These reasons make the power controlled by MCU possible .Therefore, combined with single chip microcomputer technology and V/I conversion circuit, feedback control scheme is used to design the single-chip microcomputer control of high precision pulse constant current source. Based on the use of low-dropout linear regulator chip NCP5662, SCM STC89C52, A / D converters, operational amplifiers and other devices. By controlling the   switching diode turn-on and turn-off to achieve the purpose of the pulse output. And proposes a simple way to control pulse .The current source power supply voltage is 5v. The Pulse rise time is less than 3us. And fall time is less than 1us.Pulse width and frequency can be adjusted independently. This Power is stable and reliable.
Keywords:  pulse constant current ；A/D ；NCP5662； microcontroller
目  录
1 绪论    1
1.1 恒流源的应用    1
1.1.1 在计量领域中的应用    1
1.1.2 在半导体器件性能测试中的应用    1
1.1.3 在传感器中的应用    2
1.1.4 现代大型仪器中稳定磁场的产生    2
1.1.5 脉冲式恒流源应用    2
1.2恒流源的发展历程    2
1.2.1 电真空器件恒流源的诞生    2
1.2.2 晶体管恒流源的产生    2
1.2.3 集成电路恒流源的出现和种类    3
1.3 本文研究的内容    3
2 方案选择和论证    4
2.1 总体方案选取及性能指标    4
2.1.1整体方案    4
2.1.2性能指标    4
2.2 恒流源的实现方法    4
2.2.1 晶体管恒流源    4
2.2.2 场效应管恒流源    5
2.2.3 集成运放恒流源    5
2.3恒流源的实现原理    5
2.4计算机的仿真    6
2.4.1仿真软件    6
2.4.2 Altium Desgner    6
2.4.3 Multisim    7
3 系统的硬件设计与实现    8 STC89C52单片机控制的高精度脉冲恒流源的设计与实现:http://www.youerw.com/zidonghua/lunwen_9482.html