小功率单端反击开关电源设计.pdf

摘要：本文详细论述了小功率单端反激开关电源的设计。采用交流直线式输入， 电源主电路采用反激式变换器，控制电路采用了电流控制型集成芯片UC3842。该电 源输入和输出电路采用反激式变压器相互隔离，输出和反馈回路采用光电隔离器件 MOC8102 隔离。同时，本文对输入EMI 滤波器和反馈补偿器的设计等，有关开关电 源的设计方法和关键参数设计准则做了详细阐述。 关键词：脉宽调制 反激变换器 光电隔离 EMI 滤波器 反馈补偿 Abstract ：The work introduces the design of the Flyback mode switching power supply . On alternating-current off-line input, The most important circui t of the supply adopts Flyback convertor, and the manipulative pa -rt of the c ircuit is made up of a typical PWM IC-UC3842, which works as the current control mode. The output circuits using high-Frequency trans-form er are isolated from the input circuits . The output circuits using elecrtooptical isolation component IC-MOC8102 are isolated from the out-put circuits .meanwhile, as for the design the input of the EMI-filter and Feeds back the compensator and so on, which is related to the switch -in g power supply. the design of High-frequency transformer which is the key technology in switching supply and the design guide line of its par -amet ers are analyzed in detail. Key words: PWM the Flyback mode transformer Flyback converter Electro-optical isolation EMI-filter feedback 1 1 技术指标 本课题设计的技术要求和指标： 1． 功 率： 20W; 2． 电压稳定度： 0.2%; 3．负载稳定度： 0.2%; 4 ．纹波电压： 100mV; 5．转换效率： 60%; 6．输入电压： AC 220V 7．输出标称电压： 5V; 图1 小功率单端反激开关电源设计全图 2 “黑箱”预先估算 1. 总输出功率：Pout 20W 2