单片机控制的dcdc变换器设计.doc

单片机控制的DC-DC变换器设计 摘 要 本设计通过查阅资料，了解DC-DC变换器的发展和应用现状，以及在生产应用方面的不足开关电源有其自身存在的缺点，第一个就是使用高频变压器作为传输能量的器件．开关电源通常工作在几百KHz以上，因而会产生电磁干扰，所以会影响自身或其它系统正常工作；此外，开关电源也存在着输出电压纹波较大的问题。针对其在应用方面的不足设计出一款新型的基于单片机控制的DC-DC变换器。在系统实现上，单片机由于具有电子计算机的基本组成部分和功能，同时又具备体积小，电路简单、故障率低、可靠性高和成本低廉等优点，而被应用于DC-DC开关变换器控制的系统实现。该系统以单片机通过输出PWM信号控制开关三极管的通断，从而达到控制输出电压的目的，而ADC则对输出信号进行转换并反馈给单片机分析处理，形成闭环系统。本设计分模块详细阐述了降压型DC-DC开关电源及其控制、反馈电路的设计，并分为DC—DC变换、单片机控制输出电压、单片机闭环参与控制DC—DC的输出，三个阶段说明此变换器的实现原理。可实现如同20~30V输入5~10V输出，开/闭环控制误差范围控制在很小以内。 本设计采用软硬件相结合组成实际控制系统。设计过程主要分为以下几个部分：结构模型建立，算法确定，电路设计，程序编写，总结。 关键词单片机；开关电源；PWM；ADC；闭环控制 Chip Microcomputer Abstract By searching the information, I understood the development of DC-DC converters and application status, and the lack of application in the production of switching power supply. The switching power has its own shortage. The first is to use high-frequency transformer as the energy transmission device. Switching power usually supplies the mission of a few hundreds KHz or more, and they may be electromagnetic interference and will disrupt the work itself or other systems; In addition, the switching power supply output voltage ripple there are larger issues. For deficiencies in its application ,We have to design a new design of DC-DC converter controlled by single-chip microcomputer. In the system implementation, the microcontroller as a computers basic components and functions, but also have small, simple circuit, low failure rate, high reliability and low cost advantages, which were used in DC-DC switching converter PID control system implementation. The system microcontroller PWM signal through the output transistor on-off control switch, so as to achieve the purpose of controlling the output voltage, while the ADC is to convert the output signal analysis and processing, and feedback to the microcontroller to form a closed loop system. The detailed design of the sub-module DC-DC step-down switching power supply and control, feedback circuit, and is divided into DC-DC conver