文档介绍：创新产品设计
基于电流型脉宽调制器的单端反激式稳压电源设计
姓名
学号
班级
指导老师
基于电流型脉宽调制器的单端反激式稳压电源设计
摘要:
 电源装置是电力电子技术应用的一个重要领域,其中高频开关式直流稳压电源由丁具有效率高、体积小、,以低成本的UC3842 ,应用原边检测技术去除副边反馈环,从而降低了成本.
介绍了一种以UC3842电流型脉宽调制器进行控制,多路固定电压输出的40W开关稳压电源,根据UC3842的特性给出了详细的电路参数及高频变压器的设计方法,并对其性能进行实验,实验结果表明按此方法设计的开关稳压电源可靠性高
关键词:电流型脉宽调制器;反激式开关电源;占空比
Abstract:
  Power supply power electronics technology is an important area in which high-frequency switch-mode DC power supply from D with high efficiency, small size, light weight, and other advantages. The widely used. This paper describes a current-controlled switching power supply to low-cost UC3842 PWM control chip as the core consisting of multi-output switching power supply circuit design. Of the design of high-performance ASIC UC3842, the original application Edge detection technology to remove Vice-side feedback loop, thereby reducing costs.
, Introduced a UC3842 current-mode pulse-width modulator control, multi-channel fixed output voltage 40W switching power supply, according to the characteristics of the UC3842 is given a detailed high-frequency transformers and circuit parameters of design, performance and Experiment results show that this method of switching power supply design, high reliability
Key words: current-mode pulse-width modulator; flyback switching power supply; duty cycle
一方案论证与比较
方案一:采用中小规模集成电路构成的控制电路。外围器件较多,实现较复杂,容易出故障。
方案二:采用可编程逻辑器件或ARM等32位高端机构成的控制器,功能较强。
经过比较,选择方案二。
二工作原理
1单端反激式变换器:单端反激式变换器又称电感储能式变换器,工作原理如图l所示,当开关管S1被PWM脉冲激励而导通时,次级整流二极管D1截止,,此时NP相当于一个纯电感,流过NP的电流线性上升,电源能量以磁能形式存储在电感中:当开关管S1截止时,由于电感电流不能突变,原边绕组两端电压极性反向,副边绕组上的电压极性颠倒使D1导通,原边储存的能量传送到副边,提供负载电流,同时给输出电容充电.
    单端反激式变换器通常采用加气隙来增大可工作的磁场强度H,减少剩余磁感应强度;当反激式变换器处于连续工作模式时,气隙可有效防止磁芯饱和,因而可增大电源的输出功率,减少变压器磁芯损耗,进一步提高开关频率.
2 UC3842结构和功能介绍:   UC3842芯片是一种单端隔离式电流型脉宽调制集成电路,其主要特点是:
    (1)外接元件少,外围电路简单,价格便宜;
    (2)无需输入变压器,启动电流小;
    (3)具有精密的电压基准源(±l%);
    (4)大电流(1