[第一讲ACDC开关电源设计.ppt

交流开关电源(AC/DC)设计;AC/DC开关电源常用的主电路结构： 单端反激式开关电源 单端正激式开关电源 半桥式开关电源 全桥式开关电源 推拉式开关电源 开关电源的控制方式： 电压型PWM控制 电流型PWM控制 MCU、ＡＳＩＣ或DSP控制 ;B、AC/DC开关电源设计;2、单端正激式开关电源;3、半桥开关电源设计; 4、全桥开关电源;5、推换式开关电源;二、PWM控制芯片介绍 目前AC/DC常用的控制芯片有电压式和电流式两种。 1、电压式 典型芯片有：TL494;Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.;Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.;Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.;Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.;2、电流型PWM控制器;Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.;Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.;Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.;Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.;Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.;例一、AC/DC 单路输出15W开关电源设计;Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.;单端反激式输出切勿开路！！！;1.3 高频变压器设计 A、计算最大和最小直流输入电压（加到变压器初级）: ;C、输入电流峰值 取1， DMAX取0.6 D、输入电流有效值;; ;选PC40锰锌功率铁氧体磁芯RM8。 其饱和磁通密度BS在100℃下为390mT，有效截面积Ae=64mm2 ，电感系数;由初级电感量LP估算原边匝数： 考虑实际使用时变压器须加气隙，故单位匝数的电感量将下降, 故可取： NP=2×22=44匝;副边实取3匝，则对应原边调整为15.3×3=46匝;H.变压器磁饱和校验;Ｉ、变压器线径计算 原边???径：;１.４ 输入整流桥计算;1.6、输出滤波电容计算;选择２0A／３０V以上快恢或肖特基二极管 如选IR 公司的肖特基: 20TQ045 45V/20A ，VFM=0.51V, TO-220AC 如果要进一步降低输出整流管上损耗,可选用MOS管作同步整流, 或者选用碳化硅肖特基二极管。;１.８降低开关电源功耗的一些措施;例二、AC/DC 开关电源;Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Prof