电流源与电压源驱动网络变压器

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1、电流源与电压源驱动网络变压器CurrentandVoltageSourcedrivetransformerContent1.CurrentandVoltageSourcedrive2.BobSmithTermination3.Thefunctionandclassificationoftransform4.Integratedanddiscretemagnetic5.8-Coreand12-CoreMagnetic6.CMC(common-modechoke)onthecableandPHYside21CurrentandVoltageSourcedr

2、iveThedrivetypeofPHYcontainsvoltageandcurrentsourcedrive.Thecentertapshouldconnecttocapwhenusevoltagesourcedrive.Meanwhilethecentertapshouldconnecttopowerwhenusecurrentsourcedrive.ButwhichkindofdrivetypetobeusedisdeterminedbythePHY-ic.3CurrentSourceDriveCentertaptopower:Providet

3、heneededdrivecurrent4VoltageSourceDriveCentertapCap:Providelowimpedancepathforcommon-modecurrent5ComparisonofPowerConsumption6CurrentSourcepowerconsumptionTodrive1Voutputvoltageand10mAoutputcurrent,PHYhavetosink40mA,10mAgoingdownand30mAgoingdown,currentfromthecentertap.Finallyth

4、etransformerhave20mAgoingdowninN/2turnsofcoil,so20mAiswastedThetotalpowerconsumptionof4pairsdifferentialincurrentmodedriver.40mA/ch*4ch*1.8V=288mW/porttodrive+1Vonall4pairs.78VoltageSourcePowerconsumptionTodrive1Voutputvoltageand10mAoutputcurrent,thevoltagesourcehastoapply2Vbeca

5、useoftheseriestermination.Typicallythevoltagesourceisatlest2.5Vassuming1:1turnratiotransformers.Theneededcurrentisonly10mAtooutput10mA.For2.5Voperation:10mA/ch*4ch*2.5V=100mW/porttodrive+1VFor3.3Voperation:10mA/ch*4ch*3.3V=132mW/porttodrive+1V9ConclusionCurrentSourcedriverneeds4

6、timescurrentasmuchasVoltageSourcedriverandmorepowerthanVoltageSourcedriver,sonewergenerationofMarvellPHY-icuseVoltageSourceDrivertoreducepowerconsumption.(Belowforreference).Forexample,88E1318usescurrentsourcedriver,butnewerPHY-ic88E1543and88E1518usevoltagesourcedriver.Note:Itde

7、scribesthebasicdifferencebetweencurrentsourcedrivervsvoltagesourcedriverandthedifferenceintermofthevoltage,current,andpowerbetweenthetwoapproaches.Itonlydescribesthetheorynotactualsituation.10TransformandBobSmithTermination113BobSmithTerminationRobertW.(Bob)Smith’spatentedideapr

8、oposesthewaytoreducethecommonmodecurrentsonamul