基于单片机开关稳压电源设计.doc

基于单片机开关稳压电源设计 摘 要 开关电源是利用现代电力电子技术，控制开关管开通和关断的时间比率，维持稳定输出电压的一种电源。具有高效率、体积小的特点,广泛应用于各种通信、电子、电器设备领域中。 本设计由AT89S52单片机系统，PWM信号控制芯片TL494，开关电源升压主回路，A/D以及D/A，键盘输入和输出显示模块等组成。系统以AT89S52单片机为控制核心，DC-DC变换由Boost升压变换器实现，电路结构简单，转换效率高，实现电压可预置，步进电压为1V，输出电压范围为30-36V，输出电流为0-2A，由LCD液晶管显示输出电压和电流。系统由220V的市电作为电源输入，先通过变压器降压成18V的交流电，再经过整流滤波成为直流电，然后通过键盘预置电压值送给单片机，单片机通过D/A转换送给TL494形成闭环反馈回路，最后通过检测输出电压进行A/D转换送给单片机，转而由LCD显示输出电压。本系统具有调整速度快，精度高，电压调整率低，负载调整率低，效率高，输出纹波小等优点。 关键词：开关电源；AT89S52；脉冲宽度调制；直流-直流变换器 The Design of Switching Power Supply Based on SCM ABSTRACT Switching power supply is the use of modern power electronic technology,through control switch opening and closing time ratio to keep the output voltage stability.Bacause of the characteristics of high efficiency and small volume,it has been widely used in various communication,electronics, electrical equipment. The system mainly by the smallest SCM system, TL494 chip PWM control signal, the main boost switching power supply circuit, A / D and D / A component. For this system to AT89S52 core voltage can be preset, stepping voltage of 1V output voltage range of 30 to 36V, output current is 0-2A. That output voltage and current output can be displayed by the LCD tube. The system consists of 220V power input, at first through the alternating current transformer step-down into 18V, after rectifying filter become dc. Then through the keyboard preset voltage values for SCM, preset SCM by D/A transformation TL494 form close-loop feedback loop to last through the test, the output voltage on the A/D conversion to microcontroller, by the LCD display output voltage. The system has adjusted speed, high precision, low voltage adjustment, the adjusted rates low load, high efficiency, the advantages of small output ripple. Keywords: Switching Power Supply；AT89S52；PWM；DC-DC Converter 目 录 引 言 1 第1章 绪论 2 1.1 开关电源的定义 2 1.2 开关电源的发展历史 2 1.3 开关电源的分类 2 1.4 开关电源的发展方向 3 第2章 设计方案比较与论证 5 2.1 DC-DC主回路拓扑的方案选择 5 2.2 控制方法的方案选择 6 2.3 单片机的选择 6 2.4 显示模块的方