电源EMC整改指南

1、深圳市莱福德光电有限公司电源的EM窿改指南（仅供内部使用）批准：审核：拟制：EMC整改小组开关电源辐射整改小结1.开关管DS脚加20-1000pF高压陶瓷电容，对30-120M辐射干扰有一定的拟制做用。FreqfMEIz)LeveJ(dBuVTm)Margin(dBLimit(dBuV/ni)Eteading(dBuV)FactordB)Remark151,34005450145040.0045.98S.52265S90047.0670640.g3819S.S7FreqtMUz)Level(dEuV7n0Margjn(dB)R.eading(dBuV)Factor(dB)Remark133,8

2、3003259-74140.0020.6711.92251,340047.377.3740.0038858.52图2是在图1的基础上电源MO甯DS脚力口470pF1KVfe容的测试图。2,变压器外加铜钳(接电源热地)，对30K-120M辐射干扰能有效屏蔽(5-15dB)。Freq(MEz)Level(dBuVAn)MargjnfdB)Linnt(dBuV/m)ReadingfdBuV)Factor(dB)Remade132,910049.869.3640.0037.3212.54245,520057.8817.8340.00465110.97330,440044161.1640,002&

3、;2415.92458,200041.H1.1140.0024.2116.90FreqfMHz)Level(dBuV/m)blarginfdB)Lumt(dBuV/m)fceaddng(dBuVFactor(dB)Remark132,910048.ISS.1E40.0035.6412.54238,730039.7140.0028.5511.16r342,6100F39.540.4640.0028.3711.17I449,400046.63663400037.379.2679,4700413913940.0025.7315.666103.720033.O1.Q9940.00283510.6672

4、06.540040.100.1040.00234716.63图4图4是在图3基础上变压器外加铜钳屏蔽（接初级地）的测试图。3. 增大DC输出端共模电感电感量，能有效拟制30-50M辐射干扰。Freq(MHz)Leviel(<iBuV/ni)Margin(dB)Reading(dBuVFactor(dB)Remark132910039m-0.9340.0026.5312.54241,460045425424000353010.12FreqfMHz)Level(dBuV/m)Margin(dB)Linut(dBuV/ni)Reading(dBuV)Factor(dB)Remark147,46

5、0043153.1540.0033.031012图6是在图5的基础上增大DC输出端共模电感电感量的测试图。4. 输入端（靠近变压器）加CBB电容。能有效拟制30-100M辐射干扰。FreqfMH2)Levtl(dBuVZm)Margin(dB)Reading(dBuV)Factor(dB)Remark13S730038.30-1.2040,0027.6411162426100效22-0.7S40.002S,0511.17346,490039.43-0.5710002S.S91。国FreqfMHz)Ltvel(dBuV/n)Margin(dB)LinuttdBuV/m)E<eading(dBuV)Factor(dB)Remark141,640033.20-6.3040.0022.041116245,52003513-4.