多路输出开关电源毕业设计-3路解析.doc

题目 多路输出开关电源设计 学生姓名 商林杰 学生班级 电气12-6 学 电气工程及其自动化 指导教师 胥良 摘 要 开关电源电路是电力电子电路的一种,它实现了电能的变换和能量的传递。开关电源是一种高效节能型电源，在我们生活中运用的日益广泛，已经成为我们日常生活必不可少的器件。 本次的设计是多路输出开关电源，由于技术指标需求，经过方案的对比和优化，选择出推挽变换电路拓扑作为主电路，输入的电压范围是 DC20-28V，输入电压经过PWM控制、整流、滤波反馈等电路的调节，输出三路电压，分别是15V,-12V和12的直流电源输出。电路主控制芯片采用SG3525实现电压电流双闭环控制，该芯片具有欠压保护功能，使其控制MOS管的导通和截止，大大简化了电路。电路的反馈部分用光耦合器PC817,TL431L采样输出电压，通过芯片SG3525的控制，使设计出的开关电源能够稳定的输出想要得到的电压。 关键词：开关电源多路输出，电路拓扑，SG3525，PC817，TL431 Absract Switch power circuit is a kind of power electronic circuits, it implements the electrical energy transformation and energy transfer. It Is a highly efficient energy-saving power supply, switch power supply is becoming more and more widely used in our life,and it has become our daily life indispensable device. This design is multiplexed output switching power supply, demand for technical indicators, through scheme comparison and optimization, it chooses the push-pull conversion circuit topology as the main circuit, the input voltage range is the DC20-28v, the input voltage is controlled by PWM l rectifier filter the adjustment of the feedback circuit. output voltage, three road respectively is15 and 12v to 15vdc output power. Main control circuit voltage and current double closed-loop control is realized by using SG3525 chip The chip has under-voltage protection function .the control of MOS tube conductions and globe greatly simplifying the circuit. Run coupler PC817 feedback part of the circuit, TL431L sample output voltage. through the control chip SG3525, it makes the design of switch power supply can get stable output voltages.that is we want. Keywords: multi-channel switch power supply output，topology structure，SG3525，PC817，TL431 目 录 摘 要 0 Absract 1 目 录 2 第1章 绪论 4 1.1 设计背景和意义 4 1.2 发展状况 6 1.3 开关电源存在的问题 6 1.4 开关电源的分类 7 1.4.1 按电路的输出稳压控制方式进行分类 7 1.4.2 按开关电源的触发方式进行分类 7 1.4.3 按输入与输出是否隔离分类 8 1.4.4 按功率开关管关断和开通工作条件分类 8 第2章 开关电源的工作原理 10 2.