Yiming-48V汽车电子传导EMI分析与降噪--以一个 48V-12V DCDC 变换器为例.pdf

1、rev 20180504Conducted EMI Analysis and Mitigation in 48V AutomotiveCase Study Based on a 48V-12V DCDC Converter48V汽车电子传导EMI分析与降噪：以一个48V-12V DC/DC变换器为例Speaker:Yiming LiAgendaEMI challenge for 48V Automotive48V LLC Introduction and ApplicationConducted EMI Noise Analysis for Various CasesSummary and C

2、onclusionEMI Challenge for 48V AutomotivePower Architecture:48V Bus+local 48V-12VAdvantage:48V wire harness has best weight saving 12V Battery not required because:o 48V battery as a buffer for loadso HV battery charges 48V battery Easy to upgrade:in the future when more load move to 48V,only need t

3、o size the local 48V-12V DCDC w/o touching the architecture Good total Efficiency Low cost800V battery48V12V48V loads800V12V loadsACDCDCDCZCUOBCDC/DCDC/DC48V battery+charger+monitorArchitecture of Zonal Control Unit48V battery70V+Protection&Monitor 48V-12V LLC48V_Prot12V_ProtLocal loadsCANPCIeEthern

4、etProcessorSoCMCUCANLINFPD-LinkAudioIOLocal sensors/actuators1Gbps10-100MbpsEthernet switch70V Buck/PMIC70V+E-Fuse&HSSLV E-Fuse&HSS48V70V+E-Fuse&HSSNotes:1.DC/DC input voltage increases from 12V to 48V.2.An additional 48-12V DC-DC is applied for 12V power rail.Conducted EMI:Modeling and General Redu

5、ction TechniqueSpectrum of a Trapezoidal WaveVoltage(V)Time(s)=1 0 :001-20dB/dec-40dB/decMagnitude(dBuV)Frequency(Hz)20Time DomainFrequency Domain0=1=Fourier Expression of a Trapezoidal Waveform=20 sin sinrepresent the magnitude of the nth order harmonic =20 02000 1where is the envelope of the spect

6、rum sin 1 1sin 1 101200=10,=0.5,0=1,=10Magnitude(dBuV)Frequency(Hz)Spectrum of a Trapezoidal WaveVoltage(V)Time(s)=1 0 :001-20dB/dec-40dB/decMagnitude(dBuV)Frequency(Hz)20Time DomainFrequency Domain0=1=0148V to 5V,d=0.112V to 5V,d=0.4EMI Comparison,CE,150k-30MHz12V-5V,CE48V-5V,CE12dB differenceNote: