设计的磁基站LF对讲
ThisapplicationnotebuildsonapplicationnoteAN232
LowFrequencyMagneticTransmitterDesign
(DS00232).Itcoversthedesignprocesstoimplement
LFTalkbackfunctionality.AN232coverssomeofthe
magnetismbasicsanddesignprinciplestoimplement
thedrivecircuitry.LFTalkbackgenerallyreferstothe
processinwhichatranspondercancommunicateback
toamagnetictransmitterbasestationbyloadingthe
generatedmagneticfield.Bymeasuringthesmall
changesinthetransmittercoil'svoltage,usedtogener-
atethefield,thecommunications’dataisextracted.LF
TalkbackiscommonlyusedinRFID,automotive
transponders,activetransponders,andmanyother
bidirectionalLFcommunicationstopologies.
Thisdocumentwillcoverthedifferentstagesneededto
implementatypicalLFTalkbacksystemandexplain
theprocessinchoosingthedifferentstagecharacteris-
tics.Itexplainsthevariousperformanceandcosttrade-
offsmadeforthereferencedesignandhowitcanbe
adaptedtobettersuitthereadersneeds.AN912DesigningLFTalkbackforaMagneticBaseStationMAINBUILDINGBLOCKSAuthor:RuanLourensMicrochipTechnologyInc.Figure1showsthemainbuildingblocksthatmakeuptheLFTalkbacksystemdescribedinthisdocument.ThebasestationgeneratesastrongmagneticfieldbyINTRODUCTIONsettingupresonanceinaserialresonanttank.The
