DCDC模块常见电路拓扑分析

DC/DC模块电源常用的电路形式开关电源功率电路分析要点1.电容的电压不能突变,电感的电流不能突变2.流经电容的电流平均值为零,电感两端电压的平均值为零3.理想变压器电压与匝数成比且同名同极性,电流与匝数成反比且点进点出4.电容恒流充电的公式为,电感恒压储能的公式为5.变压器与电感的伏秒积必须平衡TIUC**TUIL**Buck-Boost电路工作原理：VinVoDLIoS1S1S2ULILVin-VooIIoD1-DT根据L的伏秒平衡原则：Vin*DT=(Vo+2Vd)*(1-D)TVo=Vin*D/(1-D)-2VdL*ΔIo=(Vo-2Vd)(1-D)TVds1根据L在(1-D)T时间的基本方程：ΔIo=(Vo-2Vd)(1-D)T/LDS2Vds2VinVo00.10.20.30.40.50.60.70.80.91012345678910VoD()DVo/Vin=D/(1-D)Buck-Boost电路的输入输出关系：三种基本的非隔离开关电源：VinVoLIoSDVinVoDLIoS1DS2VinVoDLIoSVo=Vin*D/(1-D)Vo=Vin*DVo=Vin/(1-D)VoVin,降压型电路VoVin,升压型电路VoVin,当D0.5VoVin当D0.5升降压型电路三种基本的隔离开关电源：VinVoSLmDVinVoLSD1D2VinVoLS1D1D2S2正激型变换器反激型变换器桥式变换器反激变换器（Flyback）工作原理（电流连续模式）：VgsIDVdsD1-DTIpIoVinVin+nVo根据变压器的伏秒平衡：ImIoVinVoGDSLmDn:1TDnVoDTVin)1(**)1(**DnDVinVoCoVLVin-nVonVoVinVds)1(DVinVdsID-p反激变换器（Flyback）工作原理（电流断续模式）：VgsIDVdsD1-DTIoVinVin+nVo根据变压器的伏秒平衡：ImIoVinVoGDSLmDn:1)1(**DnDVinVoCoVLVin-nVo’ID-p-nVoVoVo'TRVoLmIp2221根据能量守恒：LmVinDTIpVinDLmRTVo2反激变换器（Flyback）工作原理：VgsIDVdsD1-DTIpIoVinVin+nVoImVrVLVin-nVo221221LkIpCdsVrnIIppDID-p21DopDIDIIVr=？IoVinVoGDSLmDn:1LkCoLmTDVoID/)1(IpCdsLkVr*反激变换器（Flyback）工作原理：IoVinVoGDSLmDn:1LkCoVcVcRPloss=(Vc-Vin)2/RGDSLkVcRPloss=(Vc)2/R反激变换器（Flyback）工作原理：VgsIDVdsD1-DTIpIoVinVin+nVoImVrICoID-pΔVo=？IoVinVoGDSLmDn:1LkCo)1/(DIIIopDCo-IoVoDTIVCOOCDTIVOO/根据Co在DT时间的基本方程：反激变换器（Flyback）工作原理：VinVo1GLmNpLkVo2Ns2Ns1多路输出的反激变换器：)1(***11DNpDVinNsVo)1(***22DNpDVinNsVo减小交叉调整率的措施：1.尽量减少两个绕组之间的漏感。2.在辅助输出一路中加入尖峰抑制器（饱和电感）3.主路输出工作于电流连续模式。4.采用双路加权反馈的控制方式反馈控制反激变换器（Flyback）特征总结：VinVo1GLmNpLkVo2Ns2Ns1缺点：1.输出纹波电流大。2.输出控制特性非线性。3.通常需要辅助的吸收回路。4.转换效率较低。反馈控制优点：1.电路简单。2.输入电压范围广。3.容易实现多路输出。谐振复位正激变换器（ResonantResetForward)：Ion:1VinVoLoGDSVgsILVdsD1-DTIpVLIoVin/n-Vo-VoImVinΔILILLmLkCrt0t1t2t3t4Ip[t0,t1]t5LmVinDTIm/LoDTVonVinIL/)/(LmPInII谐振复位正激变换器（ResonantResetForward)：Ion:1VinVoLGDSVgsILVdsD1-DTIpVLIoVin/n-Vo-VoImVinΔILILLmLkCrt0t1t2t3t4Ip[t1,t2]t5LmLkIIVVmpc211VcV谐振复位正激变换器（ResonantResetForward)：Ion:1VinVoLGDSVgsILVdsD1-DTIpVLIoVin/n-Vo-VoImVinΔILILLmLkCrt0t1t2t3t4Ip[t2,t3]t51VcVcVrminCLDTV2谐振复位正激变换器（ResonantResetForward)：Ion:1VinVoLGDSVgsILVdsD1-DTIpVLIoVin/n-Vo-VoImVinΔILILLmLkCrt0t1t2t3t4Ip[t3,t4]t5LmCrtt14Lm,Cr的选取原则：22max2)1(1*TDCrLm谐振复位正激变换器（ResonantResetForward)：Ion:1VinVoLGDSVgsILVdsD1-DTIpVLIoVin/n-Vo-VoImVinΔILILLmLkCrt0t1t2t3t4Ip[t4,t5]t5(Vin/n-Vo)DT=Vo(1-D)T根据电感的伏秒平衡：Vo=VinD/n谐振复位正激变换器（ResonantResetForward)特征：VinVoCr缺点：1.原边开管电压应力较高。2.谐振电容的损耗大。3.宽范围输入效率很难兼顾。优点：1.电路简单。2.线性输出控制特性。3.不需要辅助的吸收回路。VinVoCrVinVoCrS1,S2VpVinDVds10050%DutyCycleZVSforLowsideswitchExcitingResetResonantResetDualSwitchForwardVinLS2S1Sa1CrD1D2有源钳位正激变换器（ActiveClampedForward)：Ion:1VinVoLoGDSSaILVdsDTIpVTIoVin/n-Vc/nImVinΔILILLmLkCrt0t1t2t3t4Ip[t0,t1]t5LmVinDTIm/LoDTVonVinIL/)/(LmPInIIS1S1Sa1-D+VT-有源钳位正激变换器（ActiveClampedForward)：Ion:1VinVoLoGDSSaILVdsDIpVTIoVin/n-Vc/nImVinΔILILLmLk-Vc+t0t1t2t3t4Ip[t1,t2]t5LkIpttVcIm)()12(S1S1Sa1-D+VT-VcLknIott/*)/()12(1td2td*副边电压的死区跟Lk和Io有关，跟原边开管的死区无关有源钳位正激变换器（ActiveClampedForward)：Ion:1VinVoLoGDSSaILVdsDIpVTIoVin/n-Vc/nImVinΔILILLmLk-Vc+t0t1t2t3t4Ip[t2,t3]t5S1S1Sa1-D+VT-)12(1tttd1td2tdSa在零电压条件下开通*原边开管的死区时间需满足：有源钳位正激变换器（ActiveClampedForward)：Ion:1VinVoLoGDSSaILVdsDIpVTIoVin/n-Vc/nImVinΔILILLmLk-Vc+t0t1t2t3t4Ip[t3,t4]t5S1S1Sa1-D+VT-1td2td激磁电流反向，变压器被复位LmTDVcIm/)1(有源钳位正激变换器（ActiveClampedForward)：Ion:1VinVoLoGDSSaILVdsDIpVTIoVin/n-Vc/nImVinΔILILLmLk-Vc+t0t1t2t3t4Ip[t4,t5]t5S1S1Sa1-D+VT-1td2td激磁电流对主开关的输出电容放电。t6=t0有源钳位正激变换器（ActiveClampedForward)：Ion:1VinVoLoGDSSaILVdsDIpVTIoVin/n-Vc/nImVinΔILILLmLk-Vc+t0t1t2t3t4Ip[t5,t6]t5S1S1Sa1-D+VT-1td2tdt5时刻副边二极管钳位主开关的输出电容放电结束。t6时刻新的周期开始t6=t0有源钳位正激变换器（ActiveClampedForward)：Ion:1VinVoLoGDSSaILVdsDIpVTIoVin/n-Vc/nImVinΔILILLmLk-Vc+t0t1t2t3t4Ipt5S1S1Sa1-D+VT-1td2tdt6=t0(Vin/n-Vo)DT=Vo(1-D)T根据电感的伏秒平衡：Vo=VinD/nVinDT=Vc(1-D)T根据变压器的伏秒平衡：Vc=VinD/(1-D)Vds=Vc+VinVds=Vin/(1-D)有源钳位正激变换器（ActiveClampedForward)：00.10.20.30.40.50.60.70.80.91012345678910VcD()VdsD()DVc=VinD/(1-D)Vds=Vin/(1-D)Vin有源钳位正激变换器（ActiveClampedForward)特征：VinVoVinVoVinVoSaSaSa缺点：1.钳位电压建立较慢，启动过程变压器易偏磁。2.对输入电压的动态响应慢。优点：1.变压器最优化复位（电压应力低）。2.输入电压范围宽。3.线性输出控制特性。4.不需要辅助的吸收回路。有源钳位正激变换器（ActiveClampedForward)：AsymmetricalFullBridgeDC/DCConverterVinVoLS1D1D2S2半桥变换器桥式变换器（BridgeTypeConverter)：VinVoLS1D1D2S2全桥变换器VinVoLS1D1D2S2推挽变换器VinVoS1D2S2半桥变换器（倍流整流）VinVoLoS1D1D2S2桥式变换器（BridgeTypeConverter)：n:1+1LmLkIpIoCBVTS1ILVds1DIpVTIoVin/2n-Vin/2nImVinΔILt0t1t2t3t4t5S2Dt6=t0T/2T/2Vc[t0,t1]变换器正半周工作，Ip,Im增加；Vc减少。LmDTVinIm/2)12/()/(CDTnIoVcC1C1VinVoLoS1D1D2S2桥式变换器（BridgeTypeConverter)：n:1+1LmLkIpIoBVTS1ILVds1DIpVTIoVin/2n-Vin/2nImVinΔILt0t1t2t3t4t5S2Dt6=t0T/2T/2VcC1CC1Vin/2[t1,t2]S1关断，变压器副边续流，原边漏感能量被S2体二极管钳位。VinVoLoS1D1D2S2桥式变换器（BridgeTypeConverter)：n:1+1LmLkIpIoBVTS1ILVds1DIpVTIoVin/2n-Vin/2nImVinΔILt0t1t2t3t4t5S2Dt6=t0T/2T/2VcC1CC1Vin/2[t2,t3]S1，S2全部关断，变压器副边续流，Lm保持不变，D1,D2电流之差为Lm。VinVoLoS1D1D2S2桥式变换器（BridgeTypeConverter)：n:1+1LmLkIpIoABS1ILVds1DIpVTIoVin/2n-Vin/2nImVinΔILt0t1t2t3t4t5S2Dt6=t0T/2T/2Vin/2VTVc[t3,t4]变换器负半周工作，Ip,Im减少；Vc增加。LmDTVinIm/2)12/()/(CDTnIoVcVinVoLoS1D1D2S2桥式变换器（Br