Smart GridSolutions Guide
Edition 1, January 2011
Smart Grid Solutions GuideA message from the CEO
www.maxim-ic.com/smartgrid i
A message from the CEO
DearEngineer,
The“smartgrid”isdevelopinginresponsetochangesinhowpeoplelive,work,travel,andplay.Itisactuallyamodern-dayrevolutionthatchangeseverythingabouthowelectricityisgenerated,stored,used,andbilled.Itencompassesnewrenewablesourcesandtheconnec-tionofnewloadslikeelectricvehicles.It’sglobal,anditaffectsusall.
ThissolutionsguidehighlightskeyareaswithinsmartgridswhereMaximbringsthemostvalue.Ouradvancedmetrologysystem-on-chip(SoC)solutionsofferthebestaccuracy
availableformeteringapplications.Theyalsoensurethedevelopmentofstandards-compliantproductsthatwillmeetfast-changinginfrastructuredemands.Ourpowerlinetechnologyenablescommunicationthroughtransformers,andourhighlevelsofintegrationreducecostsandtimetomarket.
Thisisnotaproductselectorguidelistingall6400ofourproducts.Instead,it’sacriticalselectionofthebestofourportfoliotailoredforspecificsmartgridequipmentareas.Foreachsolution,welistthebenefitsofthefeaturedproducts—whethersmallersize,moreprocessingpower,lowerpowerconsumption,orsomethingelse—inaneasy-to-readformat.Andwebackupourclaimswithhardtechnicalfactssoyoucancompareoursolutionstoyouralternatives.
Maximwasfoundedover27yearsagotocreateanalogandmixed-signalproductsthatnotonlyaddvaluetoourcustomers’systemsbutalsohelpthemtochangetheworld.Asacompanyweareproudtoofferproductsthatenabletoday’ssmartgridrevolution.
YouwillalsoseethatMaximremainsfocusedonbeingtheleadingsolutionsproviderforindustrialequipmentincludingsmartgridproducts,bothwithinnovativeICsandknowledgeablesupport.
Finally,IwelcomeyourquestionsandcommentsaboutMaximandthissolutionsguide.Letmeknowwhatyouthink.Youcanreachmeat:[email protected].
TunçDoluca
PresidentandChiefExecutiveOfficer
Smart Grid Solutions Guide
ii MaximSmart Grid Solutions
Innovation Delivered and Maxim are registered trademarks of Maxim Integrated Products, Inc. © 2011 Maxim Integrated Products, Inc. All rights reserved.
Smart Grid Solutions GuideTable of contents
www.maxim-ic.com/smartgrid iii
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Smart metersOverview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Featuredproducts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Recommendedsolutionstable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Power-grid monitoringOverview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Featuredproducts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Recommendedsolutionstable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
CommunicationsOverview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Featuredproducts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Recommendedsolutionstable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Energy measurementOverview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Featuredproducts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Legal notices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Table of contents
iv MaximSmart Grid Solutions
Smart Grid Solutions Guide
Smart Grid Solutions GuideIntroduction
www.maxim-ic.com/smartgrid 1
Meeting future energy challenges today
Thesmartgridrepresentsanewvisionforhowwecanharnesstechnologytorenewenergyinfrastructure,redefineourrespon-sibilitiesasenergyusers,and,ultimately,conservevitalenergyresources.
Smartgridarchitectsfacemanychallengesinrealizingthisvision,notleastofwhichischoosingsolutionsthatofferacost-effectiveupgradepath.Thesheerscaleofthisinfra-structuralchallengenecessitatesawell-definedstrategicroadmap.Toavoidstrandingassets,theselectedsolutionmustbebothcompatiblewiththeexistinginfrastructureandscalabletomeetfutureneeds.
Systemdesignersmustkeepupwithaconstantlychangingregulatorylandscape.Thistaskcanbegreatlyeasedbychoosingasolutionspartnerwhounderstandstherequirementsofdifferentcountries,andworkscloselywithindustryconsortiatodevelopstandards.
Maxim is a proven leader in smart energyMaximhaslongbeenregardedasaleaderinpower-savingtechnology.Overtheyears,wehavepioneerednewtechniquesforbatterymanage-ment,high-efficiencypowerconversion,andlow-powerdesign.
Todayweareapplyingourexpertisetosmartenergyapplications,includingenergymeteringandmeasurement,power-distributionautomation,smartgridcommunica-tions,hybridautomobiles,andLEDlighting.
In2010,weexpandedoursmartgridofferingthroughtheacquisi-tionofTeridianSemiconductor.ThisacquisitionfirmlypositionsMaximasthetechnologyleaderforenergymeteringandmeasurement.
Withmorethantwodecadesofexpertiseand50millionICsshipped,Teridianhasdefinedtheleadingedgeofthesystem-on-chip(SoC)energy-measurementmarket.SystemdesignersworldwideusetheseSoCstoacceleratesystemdevelopmentandreduceengineeringcostsfornewenergy-meteringandmeasure-mentapplications.
Maxim’spowerlinecommunicationstechnology(G3-PLC)isenablingnewsmartgridapplicationsaroundtheworld.G3-PLCiscurrentlybeingdeployedinFrancetoimplementanadvancedmeteringinfrastructureforover35millioncustomers.Italsoservesasabasetechnologyforinterna-tionalstandardsdevelopmenteffortssuchasITUG.hnem/G.9955andIEEE®P1901.2.
Maxim’sPLCandSoCsolutionsarecomplementedbyabroadportfolioofanalogandmixed-signalsolutions,includingpower-managementICs,real-timeclocks,RFcommunications,andinterfaceproducts.AllofwhichmakesMaximatrueend-to-endsolutionsproviderformeteringandothersmartgridapplications.
A committed innovation partnerMaxim’sapplicationexpertsworkcloselywithsystemdesignerstodeveloptechnologyplatformsthatmeetimplementationrequirementsforbackwardscompatibility,scalability,andcompliancewithinternationalstandards.
Thissolutionsguideaddresseskeychallengesfacingsmartgridarchitectsanddesigners.ItdetailshowMaxim’ssolutionsareenablingcustomerinnovationsincommun-ications,distributionautomation,andenergymeasurementandmetering.
Design with Maxim
Develop smarter, more-precise systems
• Proprietaryprocesstechnologiesyieldthetightesttolerances,lowestnoise,highestvoltage/currentcapabilities,andgreatestintegration
• Maxim’sbroadproductportfolioenablesend-to-endsolutionsoptimizedforperformance-drivenapplications
• State-of-the-artcommunicationstechnologiesbuildintelligenceintogridinfrastructure,fromthesubstationtothecustomerpremise
Accelerate your time to market
• BenefitfromtheimplementationexpertisethatMaximhasgainedwhileworkingwithindustryconsortia,utilities,andequipmentmanufacturers
• Acomprehensivelibraryofappli-cationnotes,referencedesigns,andsoftwaretoolsspeedsyourdesignprojects
• Flexiblesolutionsareeasilyadaptedtomeetdifferentinternationalstandards
Reduce equipment/infrastructure costs
• Advancedintegrationminimizesyourbillofmaterialsandinfra-structurecosts
• Applicationexpertisehelpsyoumaketherightsystemperformance-costtrade-offs
• Integratedprotectionsandindustrial-gradetemperaturerangesensurethatyourdesignsurvivesreal-worldconditions
2 MaximSmart Grid Solutions
Smart Grid Solutions Guide
Smart metersOverview
www.maxim-ic.com/smartgrid 3
Smart meter block diagram. For a list of Maxim's recommended smart meter solutions, please go to: www.maxim-ic.com/smartmeter.
Smart meters
OverviewUtilitycompaniesworldwidehavebegundeployingsmartmeterstoserviceresidentialandcommercial/industrialmarkets.Smartmetersdeliverarangeofbenefitsincludingloweroperationalandcapitalexpenses,supportfornewservices,andimprovedoperationalcontrol.
Smart meter requirementsDeploymentofsmartmetersisfarfroma“one-size-fits-all”undertaking.Manufacturersmustaccountforthevaryingregulatoryrequirementsofeachregion,aswellasthedifferentfunctionalitiesandservicesrequiredfordifferentmarkets.
InNorthAmerica,forexample,automatedmeterreading(AMR)regulationsdictatethefrequencyofmeterreadinganddatatransmission.Theyalsospecifytheamountofdata
thatmustberetainedlocallyatanygivenpointintime.Becausecommu-nicationsarenotalwaysreliable,someoftheseregulationsrequireutilitiestostoretwoormoretransmissionstomeetbillingrequirements.Thisrequirementincreasestheamountoflocalon-chipmemoryneededforsmartmeterICs.Asaresult,theregula-torypressuresofspecificjurisdictionshaveadirectimpactonthedesignofsmartmetersdowntothechiplevel.
Anothermajordriverofsmartmeterfunctionalityisimprovinglocalantitamperingcapabilities.Thisisespeciallyimportantindevelopingmarketswhereelectricitytheftaccountsforalargepercentageofoverallpowerusage.Theabilityofsolid-stateelectricitymeterstodetectandpreventtamperingcansignificantlyimprovecontrolandcostrecoveryforutilitycompanies.Hereagain,high-levelantitampering
objectivesarebothdrivingtheadoptionofsolid-statemeteringanddictatingrequiredfeaturesetsatthechiplevel.
Finally,thepromiseofimprovingservicetocustomersrepresentsanimportantgoalofsmartmetering,especiallyoverthelongterm.Byenablingcustomerstobettermanagetheirownenergyusagethroughincentive-basedprograms—suchasdirectloadcontrol,interruptiblerateagreements,anddemandbidding/buyback—smartmeteringcanhelputilitiesmanageoverallenergyconsumptionpatternsandcopewithpeak-demandchallenges.Withtherightcapabilitiesbuiltintochip-levelsolutions,smartmeterdeploymentscaneffectivelylaythegroundworkforexpandedcustomer-servicefunctions,suchaswirelessintegrationwithther-mostatstoautomaticallyadjustusageduringpeak-demandperiods.
OPTIONAL EXTREME ACCURACY COMPONENTS
ACCURATE RTC
VOLTAGE/CURRENTSENSORS
DATA COMMUNICATIONS
ISOLATED/NONISOLATED POWER DC-DC
RELAY DRIVER
MAXIM SOLUTIONUSER
INTERFACE MEMORY
METERING SoC(ADC/CPU/DSP)
TRANSFORMER DRIVER
REMOTE-DISCONNECT RELAY
SUPERVISOR
TAMPERDETECTION
VOLTAGE REFERENCE
FOR RS-232/RS-485 DESIGNS
Smart metersOverview
4 MaximSmart Grid Solutions
Formetermanufacturersservicingglobalutilitymarkets,theabovecombinationofdrivingforcespresentssignificantopportunitiesandchallenges.Mostutilitycompaniesareatleastconsideringtheimplica-tionsoffuturesmartmeteringapplicationswhenmakingtoday’sdeploymentdecisions.Therefore,metermanufacturersneedtobeflexible,offeringbothlow-costmeteringsolutionsandhigh-endsmartmeteralternatives.
Onewaythatmeterdesignersareaddressingthisdilemmaisbyusingintegratedsystem-on-chip(SoC)solutionsthatcanbeadaptedacrosstheentirespectrumoffunctionalityrequirements.SoCsdeliverlowercostsbyeliminatingtheneedfordiscretecomponents.Theyalsoproviderichfeaturesetsforsmartmeteringandsimplerupgradepathswithminimumhardwareandopera-tionalcosts.
Evolution of solid-state metering architecturesTheearliestsolid-statemeterarchi-tecturescombinedmultipleICstoimplementtherequiredfunction-ality.Typically,amicrocontrollerperformedthesystemmanagementanddisplaytasks,andmultipleADCscombinedwithafixed-functionsignalprocessortohandlethemetrologyfunctions.
ThenextgenerationofmetersusedproprietarymetrologyASICsfromlargemetermanufacturerstocombineA/DconversionandDSPfunctions.However,thisarchitecturestillfellshortofprovidingthelevelofintegrationandconfigurationflexibilityneededtosupportdynamicallyevolvingmarketdemands.TheASICapproachalsorequiredahighlevelofin-houseR&Dinvestmentandentailedrelativelylongcyclesforthecreationofeachnewrevisionoffunctionality.
IntegratedSoCsolutionsaddresstheselimitationsbyoptimizingfor
cost,performance,andflexibility.Theyalsoshortentimetomarketandreducecomponentcount.
Multiconverter vs. single-converter designsTwoshortcomingsofthetraditionalmulticonverterarchitecturearereducedaccuracyfromchannel-to-channelcrosstalkandhighbill-of-materials(BOM)costs.Thesedesignstendtocarrycrosstalkbetweenchannels,necessitatingadditionalhardwareandfirmwareprecautions.Additionally,theyrequireacostlierdifferentialmodetoachieveawideanaloginputrangeof2000:1.
AkeyinnovationinthedevelopmentofintegratedmeteringSoCshasbeentheSingleConverterTechnology®approachfromTeridian.Thisarchitec-turestreamlinesthemetrologyfunctionsbycombiningasinglesigma-deltaADCwithseveralmultiplexedinputsandaprogrammablereal-timecomputationengine(CE).ThistechnologyprovidesflexibilityforcustomizingtheDSPtoutilityrequirementswithminimalupgradestothehardwareinfrastructure.
MultiplexedsystemsofferlowercostcomparedtoarchitecturesthatdedicateseparateADCstoeachchannel.Multiplexeddesignsachievereducedchannel-to-channelcrosstalkbyusingswitchingcircuitrytoscanthroughanumberofinputchannels,samplingeachoneinrotationforprocessingbythesingleADC.
Themultiplexedapproachisparticu-larlywellsuitedforapplications,suchaspowermanagement,withseparatesignalsthataresimilarinnature.Akeyrequirementisthepreservationofphaseinformationbetweenthechannels.ThiscapabilityenablestheCEinamultiplexedsystemtoperform“simultaneous”measurementsacrossdifferentchannels.SoCsthatuseasingle-convertermultiplexing
approachprovidegainuniformity,offsetuniformity,reducedchannel-to-channelcrosstalk,anddesignflexibility.Altogether,thisyieldsalower-cost,high-accuracysolutionwithwiderbandwidth(2000:1)formeasurement.
AnaddedbenefitoftheseSoCsistheirfield-programmablefirmware.Becausethefirmwareforthereal-timeCEiseasilyupgradeable,designerscanconfigurethehardwareformeasurementsutilizingvariouscurrentsensorssuchascurrenttransformers,Rogowskicoils,andcurrentshunts.Thisalsofacilitatessupportforthetamperingtechnologiesrequiredbyutilities.
Smart meter requirementsAutomated meter reading
AMRsystemsaretypicallyimple-mentedusingoneoftwoapproaches,dependingontheregulatoryenviron-mentfortheparticularcountryandjurisdiction.Oneapproachusesrelativelyhigh-functionalitymetrologycapabilitiesatthemeteringendpoint,whiletheotherapproachfocusesonlowercostandsimplerfunctionality.
Aspreviouslymentioned,someregulatoryjurisdictionshavestrictrequirementstoavoidthelossofdataandensuremeteringaccuracyforbillingpurposes.Withreadstakenatrelativelyshortintervals(every15minutes),theaccumulateddataisthencommunicatedatlongerintervals(every8hours).However,theregulationscompensateforpotentialcommunicationsfailuresbyrequiringthatatleasttwodatabuildsalwaysberetainedatthemeteringpoint.Thismeansthatthemetrologychipmustbecapableofstoringupto16hoursofdata.
InregulatoryenvironmentsthatplacelessstringentdemandsontheAMRprocess,utilitiesminimizethecostofmetrologyfunctionalityatthemeter(unlesstheydeterminethatapositivepaybackcanbeachieved
Smart metersOverview
www.maxim-ic.com/smartgrid 5
byusinghigherendfunctionalityforantitamperingpurposes).
Thereislong-termpotentialforcostsavingsbycombiningtheAMRfunctionsdirectlyintothemetrologySoC.Yet,thisisunlikelytobepracticalinthenearterm,dueprimarilytofragmentationofAMRcommunicationsmethodologies.Communicationlinksmaybebasedonmodems(eitherfixedlineorcellularwireless)orpowerlinecommunications(PLC),withtheBOMcostrangingfrom$3forPLCuptomorethan$20forcellularmodems.
Field programmability
Deployinghigherendmetrologychipsthatallowforfieldprogramma-bility(viafirmware)enablesutilitiestobringdownbothoperationalandcapitalinvestmentcostsoverthelongterm.Thisextendstheusefullifeoftheinfrastructureandhelpstojustifysmartmeteringinvestmentswithinrate-basedcalculations.
Fieldprogrammabilitygivesutilitiesmuchgreaterflexibilitytoadjustpoliciesinresponsetochangingenergyusagepatterns.Forexample,thespecifictimesofdaysetforpeak-ratepricingpoliciesmayneedtobeadjustedassignificantnumbersofusersshifttheirenergyconsump-tion,orinresponsetoseasonalfluctuations.Remoteupgradesviafirmwareallowutilitiestoquicklytailortheirrateincentivesforcustomerstohelpsmoothoutpeakdemandwhiletrackingdynamicchangesinpeak-usagepatterns.
Energy-management services
Smartmeteringgivesutilitiesreal-timevisibilityintousagepatterns.Moreoever,itenablesthemtopromotedemand-sidemanagement,empoweringcustomerstobettermanagetheirownusage.Forinstance,theCalifornianutilityPG&Eplanstooffercustomersenhancedoptionssuchasmonitoringtheir
hour-by-hourusageontheInternetandadjustingtheirusagetotakeadvantageofincentiverates.Inaddition,thereareplansforenablingwirelessintegrationofsmartmeterswithcustomers’thermostats.Thiswillallowminorpre-agreedadjust-mentstoautomaticallybemadetotemperaturesettingsduringpeakperiodsinexchangeforanoverallratereduction.
Smartmeteringalsoopensupthepossibilitiesforimplementingsub-meteringstrategieswithinlargerbuildings.Byusingasinglesmartmeterwithmultidropcommunica-tionlinkstoindividualcustomers,autilitycaneliminatetheneedforindividualmeterswhilestillprovidingahighdegreeofvisibilityintoeachcustomer’senergyusage.
Security mechanisms
Antitamperingisanotherkeydriverforsmartmetering,especiallyindevelopingcountrieswhereelectricitytheftisamajorcostconcernforutilities.Forexample,ithasbeenestimatedthatasmuchas40percentofthepowerusageinBrazilisstolen.
Typicaltamperingtechniquesvaryfromintrusivemeanssuchasbreakingthemeterhousingandjammingthemechanismtomoresubtlemethodslikeapplyingmagnetstotheoutsideofthemetertosaturatemagneticcomponents.Someattempttoalterthechar-acteristicsoftheloadbyaddingcapacitance,half-waverectifiedloads,orinstantaneoushighcurrents.Othersmaybypassthemeter,whollyorinpart,whichcancauseanincreaseintheACcurrentflowingthroughthemeter’sneutralterminals.
Deploymentofmoresophisticatedsolid-statemetrologyenablesadvancedantitamperingmeasure-mentssuchasthereflectedload(VAR-hours),neutralcurrent,DCcurrentsinvokedbyrectifiedloads,
anddetectionofambientmagneticfields.SubstationmetersmayalsobeusedtodetectdiscrepanciesbetweenthetotalbilledandthetotalgeneratedpowerandreportthemviaanAMRnetwork.Inordertoprosecuteandrecoverthecostsofstolenenergy,detailedinformationsuchastheexacttimesandamountsofenergytheftarecriticalpiecesofevidencethatcanbecapturedthroughsmartmeteringtechnology.
Chip-level feature require-ments for smart metersSystem on chip
Itisclearfromtheevolvingmarketrequirements,jurisdictionalregu-latorydifferences,andvaryingimplementationapproachesthatasingle,universalsolutionisnotpossible.However,byusinghighlyintegrated,flexiblyconfigurableSoCmeteringsolutionsmanufacturerscanbringdowntheirR&Dcostsandimprovetheirabilitytoservetheentirerangeofmarketrequirements.Thisapproachalsohelpsfuture-proofmeterarchitecturestomeetemergingrequirements.
KeyingredientsofsmartmeterSoCsinclude:
• Flexible,multiple-portcommuni-cationsoptionstosupportAMRlinks,integrationwithlocaldevicessuchasthermostats,andmultidropsubmeteringtopologies
• StreamlinedmultireadprocessingcapabilitiessuchastheSingleConverterTechnologyapproachtoreduceunitcostbymultiplexinginputsthroughadelta-sigmaADCinconjunctionwithaprogramma-blecomputeengine
• Supportforavarietyofsensorinputswithminimumhardware;abilitytoadjustfortemperatureandotherenvironmentalvariationsforimprovedefficiencyandaccuracy
Smart metersOverview
6 MaximSmart Grid Solutions
• Field-upgradeablefirmwaretoextendtheusefullifeofthemeteringsolutionandallowpoliciestobedynamicallyadjustedtooptimizeenergyusage
• Polyphasemonitoringandanalysiscapabilitiestohelpmanageenergyconsumption,enableloadanalysis,andoptimizemotorfunctions
• LCDinterfacecapableofsupport-ingmultiplevoltagesandscreenresolutions
• Variouslevelsofinternalflashmemorysizes,alongwithexternalmemory-managementcapabilitiestosupportawideportfolioofdatastorageoptions
• Severaltamper-detectionmecha-nismstopreventenergytheft;supportforcurrenttransformers,Rogowskicoils,andcurrentshuntsalongwiththeircombinationalcurrent-sensingmechanisms;opencurrent-sensordetection
• Abilitytoworkwithsingle-wirepowermeasurementforspecialtamper-detectionconditionsforsingle-andpolyphasepowermeasurements
• Built-inreal-timeclock(RTC)functionality
Real-time clock
ManymeteringAFEsintegrateareasonablyaccurateRTC,whichmaydriftasmuchas60minutes/year.Thisinaccuracyshouldnotbeaproblemifthemeterisconnectedtoasmartnetworkthatperiodicallyresynchro-nizestheRTC.Ifthemeterisnotconnectedtosuchanetwork,end
customerswillexperiencesignificantbillingdiscrepanciesovertime—unless,thatis,ahighlyaccurateRTCisused.
Maximhaslongofferedtheindustry’smostaccuratetimekeepingsolutionsformeteringapplications.RTCssuchastheDS3231monitoranonboardtemperaturesensorandadjusttheloadcapacitanceofanembeddedcrystalinordertocompensateforthenaturaltempera-turevariationofthetuningforkcrystal.Becausethecrystalanddiearecalibratedacrossthefulloperatingtemperaturerangeasaunit,theresultingfrequencyaccuracyisbetterthananycompetingtechnology.Theseproductsexceedtherigorousstandardsfortimekeepingaccuracyinmeteringapplicationsandarearmedwithamultitudeofadvancedfeatures.Mostimportantly,theyeliminatetheneedforusercalibra-tion,providingahighlyaccuratesolutionstraightoutofthebox.
Maxim’snewMEMS-basedRTC,theDS3231M,extendsthebenefitsoftheDS3231.Thedevice’sall-siliconresonatorenablesthelow-frequencyandlow-currentcharacteristicsofthecrystal-basedDS3231tobemigratedtoasmallerpackage.Additionally,theDS3231Moffersextremeresilienceagainsthigh-temperatureassemblyprocesses,canwithstandshockandvibrationinexcessof20Gs,andincludesoffsetsforaging.
AttheheartoftheDS3231Misatemperature-compensatedsiliconoscillator.Basedonmeasurements
fromtheDS3231M’sonboardtemperaturesensor,atemperature-compensationalgorithmauto-maticallyadjuststheresonantfrequencytoaccountfortempera-tureeffects.Thisapproachensuresextremelytightaccuracyovertemperature.Unlikecrystal-basedproducts,theDS3231Mexhibitslessthan±0.5ppmoffrequencyshiftafterhigh-temperaturereflows,anditmaintainsflatfrequency-stabilitycharacteristics(<±5ppm)overtheentire-40°Cto+85°Ctemperaturerange.
SummaryByleveragingtheflexibleSoCfeaturesetdescribedabove,manufacturerscaneffectivelyaddresstherangeofmeteringoptions—fromlow-costfixed-functiondevicestopremiumdevicesthatofferamplememory,reprogrammability,andhighaccuracy.Asthemarketforsmartmeterscontinuestoevolve,thisflexibilitywillenablemetermanufac-turersandutilitycompaniestoadapttotheneedsofcustomersandthedictatesofregulatoryauthorities,whilesimultaneouslyoptimizingoperationalefficiencyandprofitability.
www.maxim-ic.com/smartgrid 7
Smart metersFeatured products
Energy-meter SoCs reduce cost while improving design flexibility and accuracy
71M6541D*/41F*, 71M6542F* (single phase) 71M6543F*/43H* (polyphase)
TheTeridian71M6541D/41F/42F(singlephase)and71M6543F/43H(polyphase)arehighlyintegrated,flexiblemeteringSoCsthatsupportawiderangeofresidential,commercial,andindustrialmeterapplicationswithuptoClass0.2accuracy.Thedevicesincorporatea5MHz8051-compatibleMPUcoreanda32-bitcomputationengine(CE);alow-powerRTCwithdigitaltemperaturecompensation;upto64KBflashmemoryand5KBRAM;andanLCDdriver.TheproprietarySingleConverterTechnologyarchitectureincludesa22-bitdelta-sigmaADC,whichprovidesunmatchedlinearityperformanceoverawidedynamicrangeandconsumeslesspowerthanamulti-ADCimplementation.Automaticswitchingbetweenmainpowerandthreebattery-backupmodesensuresoperationalreliability.TheseSoCsoperateoverthe-40°Cto+85°Cindustrialtemperaturerange.The71M6541D/41Farepackagedina64-pinlead-freeLQFP,andthe71M6542F/43F/43Harepackagedina100-pinlead-freeLQFP.
The71M6541D/41F/42Fand71M6543F/43HmeteringSoCsalsofeatureaproprietaryisolationtechnology.Byusinglow-costresistiveshuntsandoptionalinterfacestooneoftheTeridianisolatedsensors(71M6601*,71M6103*),thesemeteringsolutionseliminatetheneedforexpensive,bulkycurrenttransformers.This,inturn,reducesBOMcostsandcasingsizerequirements.Themeteringdesignwillalsobenefitfromimmunitytomagnetictamperingandenhancedreliability.
Acompletearrayofsoftwaredevelopmenttools,demonstrationcode,andreferencedesignsisavailable.ThesetoolsenablerapiddevelopmentandcertificationofmetersthatmeetallANSIandIECelectricitymeteringstandardsworldwide.
Benefits
• Measurement accuracy meets even the most aggressive global standards
– ExceedstheIEC62053/ANSIC12.20standards
– 0.1%accuracyover2000:1currentrange– MeetsClass0.2accuracy(71M6543H)
• High integration and programmability meet changing customer requirements
– 8-bitMPU(80515);upto5MIPS– Dedicated32-bitCE– 64KBflashand5KBRAM(71M6541F/42F/43F/43H))
– 32KBflashand5KBRAM(71M6541D)– Supportupto51digitalI/Opins(71M6542F/43F/43H)
– LCDdriversupportsupto336pixels(71M6542F/43F/43H)
– TwoUARTsforIRandAMR– IRLEDdriverwithmodulation
• Accelerate meter development– Completearrayofin-circuit-emulation(ICE)anddevelopmenttools
– Flashprogrammingandfirmwaredevelopmenttools
– Programminglibrariesandreferencedesigns
– Third-partyprogrammingtoolsandsupportservices
• Improved reliability and cost savings – Usingshuntsinsteadofcurrenttransformers(CT)lowersBOMcosts
– EliminatethecostofcopperwireneededforCTs
– Usingshuntsallowssmallermeterenclosure
– Usingshuntsenablesgainmagneticfieldimmunity
*Future product—contact the factory for availability.
(Block diagrams on following pages)
8 MaximSmart Grid Solutions
Smart metersFeatured products
Energy-meter SoCs reduce cost while improving design flexibility and accuracy (continued)
The 71M6543F/71M6543H polyphase metering SoCs are ideal for commercial and industrial applications.
IADC0IADC0
TXRX
RXMODULATOR
TX
MUX AND ADC
POWER SUPPLY
71M6543F*71M6543H*
VREF
SERIAL PORTS
POWER-FAULTCOMPARATOR
SPI™INTERFACE
TEMPERATURESENSOR
PWR MODECONTROL
REGULATOR
BATTERYMONITOR
LCD DRIVERDIO, PULSES
OSC/PLL
COMPUTATIONENGINE
MPURTC
TIMERS
ICE
RAM
IN**
IC
IB
IA
VC
VB
WAKE-UP
VBAT
V3P3A V3P3SYS GNDA GNDD
VBAT_RTC
COM0...5SEG
SEG/DIO
DIO
V3P3D
XIN
XOUT
VA
C
B
A
NEUTRAL LOAD
SHUNT CURRENT SENSORS
RESI
STOR
-DIV
IDER
S
NOTE:THIS SYSTEM IS REFERENCEDTO NEUTRAL
NEUTRAL
**IN = NEUTRAL CURRENT
AMR
PULSES,DIO
I2C OR MICROWIRE®
EEPROM
LCD DISPLAY
BATTERY
RTCBATTERY
32kHzHOST
IR
71M
6103
*
71M
6103
*
71M
6103
*
PULSE TRANSFORMERS
FLASHMEMORY
(Block diagram on next page)
*Future product—contact the factory for availability.
www.maxim-ic.com/smartgrid 9
Smart metersFeatured products
The 71M6541D/71M6541F single-phase metering SoCs are ideal for residential and POL applications.
IADC0IADC0
TXRX
RXMODULATOR
TX
MUX AND ADC
POWER SUPPLY
71M6541D*71M6541F*
VREF
SERIAL PORTS
POWER-FAULTCOMPARATOR
SPIINTERFACE
TEMPERATURESENSOR
PWR MODECONTROL
REGULATOR
BATTERYMONITOR
LCD DRIVERDIO, PULSES
OSC/PLL
COMPUTATIONENGINE
MPURTC
TIMERS
ICE
RAM
WAKE-UP
VBAT
V3P3A V3P3SYS GNDA GNDD
VBAT_RTC
COM0...5SEG
SEG/DIO
DIO
V3P3D
XIN
XOUT
IAPIAN
IBPIBN
VA
LINE
NEUTRAL
LOAD
SHUNT
SHUNTRE
SIST
OR-D
IVID
ERS
LINE
NEUTRAL
LINE
AMR
PULSES,DIO
I2C OR MICROWIREEEPROM
LCD DISPLAY
BATTERY
RTCBATTERY
32kHzHOST
IR
PULSETRANSFORMER
71M6601*
NOTE:THIS SYSTEM IS REFERENCED TO LINE
FLASHMEMORY
Energy-meter SoCs reduce cost while improving design flexibility and accuracy (continued)
*Future product—contact the factory for availability.
10 MaximSmart Grid Solutions
Smart metersFeatured products
Highly accurate MEMS RTC is less sensitive to shock and vibration than traditional clocksDS3231M
TheDS3231Misahighlyprecisereal-timeclock(RTC)basedonMEMSresonatortechnology.Itmeetsthecorerequirementsforaccuracy,stability,power,andcompliancetestingforsmartmeters.
ThisinnovativeRTCprovidestemperature-compensatedtimingaccuracyof±0.5s/day(<±5.0ppm)from-40°Cto+85°C.TheMEMStechnologymakestheDS3231Mlesssensitivetoshockandvibrationthantraditionalcrystal-basedclocks.Itisalsolesssensitivetoaccuracydrift,whichisquitecommonwithagingquartzcrystals.
TheDS3231Misalow-powerdevice(<3.0µA)thatprolongsbatterylife.Switchingautomaticallybetweenthemainandbatterypower,itmeetstheindustryrequirementfordual-supplyoperationasasafeguardintheabsenceofmainpower.
TheDS3231M’saccuracyandstabilitymakeitparticularlysuitableformultitariffmetering.Withnocrystaltoconsumespaceandaddcost,itisalow-costsolutionfortime-basedbillingandratechargesdirectlyatthemeter.Itisaviableoptionformeteringnetworksthatdonotdistributetime-of-dayinformationbetweenmeters,butmustmaintainanaccuratetimebaseatthemeter.
Benefits
• Meets the four core timing require-ments for smart metering
– Accuracy(<±5.0ppm)– Stability(<±5.0ppm)– Power(<3.0μA)– Compliancetesting(1Hzoutput)
• Highly rugged, dependable solution– ±5ppmlifetimeaccuracy– Optimizedforhighshockandvibration:>20,000g
– Requiresnospecialhandlingduringultrasoniccleaningvs.quartzcrystals
• Safeguards against power loss– <3.0μApowerconsumptionextendsbatterylife
– Dualsupplyoperation– Automaticswitchingbetweenmainpowerandbatterypower
• Reduces cost and saves space– MiniatureMEMSresonatoreliminatesthecostofaquartzcrystal
– Nousercalibrationrequired,thusreducingcost
– 16-and8-pin(150mil)SOpackages– Pincompatiblewithcrystal-basedDS3231SRTCs
Block diagram of the DS3231M RTC.
N
N
TIME-BASERESONATOR
TEMPSENSOR
INTERRUPTOR 1HzSELECT
DIVIDER
INT/SQW
1Hz
DIGITALADJUSTMENT
FACTORY TRIM
N
32kHZ
SDA
GND
SCL
VBAT
VCC
RST
CLOCK/CALENDARWITH ALARM
CONTROL AND STATUSREGISTERS
I2CINTERFACE
POWERCONTROL
DS3231M
www.maxim-ic.com/smartgrid 11
Smart metersRecommended solutions
Recommended solutions
Part Description Features Benefits
Metering SoCs
71M6531/71M6532 Residential metering SoCs with an MPU core, RTC, in-system programmable flash, and LCD driver
Multiple UARTs, I2C/MICROWIRE interface, and up to 30 DIO pins; support 2-, 3-, and 4-wire single-phase and dual-phase residential metering; tamper-detection mechanisms
High integration and field programmability enable designers to adapt to changing customer requirements, speed time to market, and lower BOM cost
71M6533/71M6534 Polyphase metering SoCs with 10MHz, 8051-compatible MPU core; low-power RTC; 128KB flash; and LCD driver
Advanced power management with less than 1µA sleep current; selectable single-ended or differential current sensing; large-format LCD driver
Higher sampling rate and larger code space offer customers ability to extend metrology functionality and implement advanced functions such as simultaneous broadband/narrowband
71M6541D*/ 41F*/42F*
Highly integrated single-phase metering SoCs
Exceed IEC 62053 and ANSI C12.20 standards; embedded isolated-sensing technology
Measurement accuracy meets even the most aggressive global standards; offer flexibility in selecting interface
71M6543F*/43H* Highly integrated polyphase metering SoCs Exceed IEC 62053 and ANSI C12.20 standards; embedded isolated-sensing technology
Significantly reduce BOM and enclosure size by eliminating the need for current transformers in polyphase designs
Real-time clocks (RTCs)
DS3231M Extremely accurate, MEMS-based, I²C RTC All-silicon MEMS resonator; requires no user calibration; ±5ppm (±0.432s/day) timekeeping accuracy over -40°C to +85°C
Reduces design time; minimizes piece-part count in manufacturing lines; provides enhanced aging characteristics and lower sensitivity to shock and vibration; improves long-term accuracy
DS3231 Extremely accurate, I2C RTC with TCXO and crystal
Better than ±2min/yr accuracy (< ±4ppm) over -40°C to +85°C; requires no user calibration
Single-chip timing solution improves accuracy and lowers design complexity over discrete solutions, which typically require a crystal, RTC, temperature sensor, and microprocessor, as well as user calibration
DS3232 Extremely accurate, I2C RTC with integrated crystal and SRAM
±3.5ppm accuracy over -40°C to +85°C; 236 bytes of battery-backed SRAM
Integrated memory allows storage of battery-backed data, including billing information or configuration data
DS3234 Extremely accurate, SPI RTC with integrated crystal and SRAM
±3.5ppm accuracy over -40°C to +85°C; 236 bytes of battery-backed SRAM
Integrated memory allows storage of battery-backed data, including billing information or configuration data
Isolated power
MAX5021/22 High-performance current-mode PWM controllers for forward/flyback configuration
Universal power supply (85V to 265V); small SOT23 package; integrated startup circuit
Save board area; ideal for noise-sensitive applications
MAX17499/500 Current-mode PWM controllers with programmable switching frequency
Integrated error amplifier regulates the tertiary winding output voltage; input undervoltage lockout (UVLO)
Eliminate the need for an optocoupler and ensure proper operation during brownout
MAX5974/75 Active-clamped, spread-spectrum, current-mode PWM controllers
Active-clamp topology; regulation without optocoupler; switching frequency is adjustable from 100kHz to 600kHz
Achieve > 90% efficiency, thus reducing power consumption in synchronous forward/flyback power supplies; save space and cost by eliminating the need for an optocoupler; optimize circuit magnetics and filter elements to meet EMI requirements
(Continued on next page)
*Future product—contact the factory for availability.
12 MaximSmart Grid Solutions
Smart metersRecommended solutions
Part Description Features Benefits
DC-DC converters
MAX1725/26 12V, ultra-low-IQ, low-dropout linear regulators
20mA output; 2µA quiescent current across operating range and in dropout; reverse-battery protection
Low-power operation conserves battery life
MAX15062* 36V, 300mA DC-DC regulator with integrated FETs in 2mm x 2mm TDFN
Low quiescent current; internal compensation; synchronous operation; pulse-skip mode for light loads
High integration with small footprint saves up to 50% total board area compared to competing solutions
Transformer drivers
MAX256 3W, primary-side transformer H-bridge driver for isolated supplies
Provides up to 3W to the transformer in isolated power supplies
Saves board area; reduces design complexity; makes it easy to implement isolated power
MAX253 1W, primary-side transformer H-bridge driver for isolated supplies
Specifically designed to provide isolated power for an isolated RS-485 or RS-232 data interface
Saves board area; reduces design complexity; makes it easy to implement isolated power
Hall-effect sensors
MAX9639*/40* Low-power, single Hall-effect sensors Adjustable magnetic thresholds (MAX9639) simplify system design; ultra-low 2.6µA supply current
Provide simple open/close detection while saving power
Supervisors
MAX6854–69 Supervisory circuits with manual reset and watchdog timer
Ultra-low 170nA (typ) supply current Low-power operation decreases drain on battery
MAX16056–59 Supervisory circuits with capacitor-adjustable reset and watchdog timeouts
Ultra-low 125nA (typ) supply current Low-power operation decreases drain on battery
Voltage references
MAX6161–68 Precision, micropower, low-dropout, high-output-current voltage references in an 8-pin SO package
±2mV (max) initial accuracy; 5ppm/°C (max) temperature coefficient
Improve system precision; reduce component count and board space
Recommended solutions (continued)
*Future product—contact the factory for availability.
For a list of Maxim's recommended smart meter solutions, please go to: www.maxim-ic.com/smartmeter.
www.maxim-ic.com/smartgrid 13
Power-grid monitoringOverview
Power-grid monitoring
OverviewAdvancedpower-gridmonitoringsystemscombinepower-supplymonitoring,load-balancing,protec-tion,andmeteringfunctionstoenablesafeandefficientpowerdelivery.Theyalsoreduceoperationandmaintenancecostsforutilities.
Thesesystemsprotecttransformers,circuitbreakers,andotherequipmentatsubstations;theyenablepredictivemaintenancebydetectingandrespondingtofaultconditions;theydynamicallybalanceloadstoconserveenergy;andtheymonitorandcontrolpowerquality.Theseadvancedcapabilitiesarecriticaltoensuringuninterruptedpowerdeliveryandsupportingintelligentgrid-managementapplications.
Accuracy requirementsTherolloutofadvancedpower-gridmonitoringsystemsiscomplicatedbythevaryinginternationalstandardsthatspecifytheaccuracyrequiredforenergymeasurement.Real-time
power-deliverymonitoring,faultdetection,faultprotection,anddynamicloadbalancingrequirestringentaccuracy.Asanexample,theEuropeanUnionIEC62053standardforClass0.2equipmentrequiresmeasurementprecisiontobe0.2%ofthenominalcurrentandvoltage.Forpower-factormeasure-mentaccuracy,sample-timephasematchingshouldbe0.1%orbetter.
Polyphase measurementsPowercompaniesdistributethree-phase(polyphase)powerusinga“wye”connection.Thetermwyereferstothearrangementofthreetransformerwindingsthatjoinatacommonpoint,thejunctionoftheY.Thelinevoltagesareoffsetinphasefromeachotherby120°,one-thirdofacycle.Ifloadsoneachofthethreephasesareequal,thesystemisbalancedandnocurrentflowsthroughtheneutralline.Afourth,neutral,wireconnectstothejunctionofthewye.Itaccommo-datesimbalancedloadsacrossthelineconnections.
Power-gridmonitoringsystemstrackthevoltageandcurrentonmultiplephaseswithADCs.Theconvertersmustbesynchronizedinordertomeetstringentstandardsrequire-mentsandtoaccuratelymeasurepowerfactor.Inatypicalscheme,eachphase’spowerparametersaremeasuredwithacurrenttransformer(CT)andavoltagetransformer(VT).Thecompletesystemcomprisesfoursuchpairs:onepairforeachofthethreephases,plusaneutralpair.TheADCssimultaneouslymeasurethethreephasesandneutralvoltagesandcurrents.Theactive,reactive,apparent-energy,andpower-factorparameterscanbecalculatedfromthesampleddata,oftenbyaDSP.
Internationalandlocalstandardsalsodictatethenecessarysamplerate.Theseapplicationstypicallyrequireaccurate,simultaneousmulti-channelmeasurementoverawidedynamicrangeof90dBorbetterwithasamplerateof16kspsorhigher.ThesecapabilitiesenableanalysisofmultipleharmonicsoftheACsupply
Block diagram of a typical power-grid monitoring system. For a list of Maxim's recommended power-grid monitoring solutions, please go to: www.maxim-ic.com/grid-monitoring.
PT/CTTRANSFORMERS
µPSUPERVISOR
RTC WITHNV RAM
TOUCH-SCREEN
CONTROLLER
DIGITALPOTENTIOMETER POWER
MANAGEMENT MAXIMSOLUTION
DAC
µC
VOLTAGEREFERENCE
OPTIONAL
UART
OPTIONAL
TO COMMUNICATIONS
BLOCK(SEE pp. 25-40)
OPTIONAL OPTIONAL
OPAMP
ACTIVEFILTER
ACTIVEFILTER
OPTIONAL
OPAMP
MULTICHANNELADC
TEMPSENSOR
14 MaximSmart Grid Solutions
Power-grid monitoringOverview
aswellasdetectionofhigh-speedfaultconditions,suchasspikesandbrownouts.
Analog-input signal chainDesignersofpolyphasepower-gridmonitoringsystemsareincreasinglyrelyingonprecision,multichannelsimultaneous-samplingADCs.TheseADCssimplifythesamplingschemewhencomparedtosingleADCsthatrequiredigitalphasecompensation.SimplifyingtheADCdesignleadstoreducedsystemcost,sinceallofthetimingamongtheADCsishandledwithintheIC.
Thesimultaneous-samplingADCmustofferbetterthan90dBsignal-to-noiseratio(SNR)inordertomeetthedynamicrangerequirementsformeasuringsmallvoltagefluctuationsonlargeACsignals.Maximofferstwosimultaneous-samplingADCfamiliesthatmeettheserequire-ments:the24-bitMAX11040with
4channelsand117dBSNR,andthe16-bitMAX11044/MAX11045/MAX11046with4,6,or8channelsandmorethan92dBSNR.
ThetransformersdrivedirectlyintotheADCiftheinputimpedanceoftheADCishighenough;otherwise,aprecisionlow-noiseamplifier(LNA)isalsoneeded.Maximoffersacompletelineofamplifierswithlessthan10nV/√Hznoiseandverylowoffsets.Theseamplifiersminimizemeasurementerrorsinthesystemtoensurethehighestpossibleaccuracy.
CommunicationsAsidefromtheanalog-inputsignalchain,power-gridmonitoringsystemsneedspecializedcommu-nicationscircuitstoovercomethechallengesoftransmittingandreceivingdataintheharshgridenvironment.Detailedinformationaboutpower-gridcommunicationsisavailableonpages25–40.
Electronic calibration Allpracticalcomponents,bothmechanicalandelectronic,havemanufacturingtolerances.Themorerelaxedthetolerance,themoreaffordablethecomponent.Whencomponentsareassembledintoasystem,theindividualtolerancessumtocreateatotalsystemerrortolerance.Throughtheproperdesignoftrim,adjustment,andcalibrationcircuits,itispossibletocorrectthesesystemerrors,therebymakingequipmentmoreaccurateandaffordable.
DigitallycontrolledcalibrationDACs(CDACs)andpotentiometers(CDPots)providequickerandsimplerelectroniccalibrationthanmechanicalpots.Theyarealsomorereliable,andinsensitivetovibrationandnoise.Usingthesedevices,manufacturerscancompensateformanufacturingtolerancesduringthefinalproductiontesttomeettargetspecifications.
An example of three-phase power monitoring in a wye configuration.
MAX11046
ADC
ADC
ADC
ADC
ADC
ADC
ADC
ADC
PHASE 1
NEUTRAL
LOAD
CTTRANSFORMER
SECONDARYVT
VTTRANSFORMER
SECONDARYCT
PHASE 2
PHASE 3
www.maxim-ic.com/smartgrid 15
Power-grid monitoringOverview
Additionally,electroniccalibrationallowsforperiodicself-testandcali-brationtocompensateforenviron-mentalfactors(e.g.,temperature,humidity,anddrift)inthefield.
CDACsandCDPotsallowboththetopandbottomDACvoltagetobesettoarbitraryvoltages,thusremovingexcessadjustmentrange.Inthecalibrationdiagrambelow,alowvalueof1Vandahighvalueof2Vareselected.Toachievea0.0039Vstepsizeoverthe1Vto2Vrange,onlyan8-bitdeviceisneeded.Thisapproachreducescostandincreasesaccuracyandreliabilitybyremovinganypossibilitythatthe
circuitcouldbegrosslymisadjusted.ThehighandlowvoltagesfortheCDACarearbitraryand,therefore,canbecenteredwherevercircuitcalibrationisrequired.Thus,thegranularityoftheadjustmentcanbeoptimizedforthespecificapplication.Inaddition,CDACsandCDPotshaveinternalnonvolatile(NV)memory,whichautomaticallyrestoresthecalibrationsettingduringpower-up.
Precision voltage references SensorandvoltagemeasurementswithprecisionADCsareonlyasgoodasthevoltagereferenceused
forcomparison.Likewise,outputcontrolsignalsareonlyasaccurateasthereferencevoltagesuppliedtotheDAC,amplifier,orcabledriver.Commonpowersuppliesarenotadequatetoactasprecisionvoltagereferences.Theyarenotaccurateenoughanddriftfartoomuchwithtemperature.
Compact,low-power,low-noise,andlow-temperature-coefficientvoltagereferencesareaffordableandeasytouse.Inaddition,somereferenceshaveinternaltemperaturesensorstoaidinthetrackingofenvironmentalvariations.
ORDINARY DAC
10 BITS, 1024 STEPS
4V
GROUND
0.0039Vper step
REFIN
10-BITDAC
FB
OUT
CALIBRATION DAC
REFHI
REFLO
8-BITDAC
OUT
2V
1V
8 BITS, 256 STEPS
Ground
4V
2V
1V
Comparing the calibration range of an ordinary DAC to a CDAC.
Power-grid monitoringFeatured products
16 MaximSmart Grid Solutions
Benefits
• Saves up to $1/channel*– High-impedanceinputeliminatesexternalbuffersforprecisiondesigns
– Bipolarinputeliminatesalevelshifter– 5Vsingle-supplyoperation– Integrated20mAsurgeprotection
• Provides the highest precision– Industry-leadingSNRandTHD– True16-bitperformanceexceedstheEN50160andIEC62053requirementsforClass0.2power-gridequipment
• Simplifies design and shortens time to market
– Simultaneoussamplingsimplifiesphase-adjustfirmwarerequirements
MAX11046
TheMAX11046istheindustry’sfirsttrue16-bit,8-channelsimultaneous-samplingSARADC.Thedevice’sproprietaryarchitectureprovidesanultra-low-noise,on-chip,negativesupplyvoltage.Thisinnovativetechnologyachievestrue16-bitperformancefromahigh-impedancebipolarinputusingonlyasinglepositiveexternalsupply.PerformanceexceedstheregulatoryrequirementsforClass0.2precision(0.2%of220V)mandatedbyIEC62053.
Thehigh-impedanceinputallowsalowpassfilterpriortotheADCinputs,thuseliminatingtheneedforprecisionexternalbuffers.Thebipolarinputeliminatesalevelshifter.Simultaneoussamplingeasesthetypicalrequirementforphase-adjustfirmwareandthusspeedsenddesignsandtimetomarket.Together,thesebenefitssimplifythedesignchallengesforpower-gridmonitoringandmeasurementequipment.ThisADCperformanceisunprecedented,anddesignswillsavecost,area,andpower.
ADC’s high-impedance input eliminates external components and reduces system cost
Block diagram of the MAX11046 16-bit, 8-channel, simultaneous-sampling ADC. Eight inputs measure voltage and current signals on three phases plus neutral.
CH0 CLAMP
DATA
REG
ISTE
RS
T/H 16-BIT ADC
BIDI
RECT
IONA
L DR
IVER
S
CH7 DB0
DB3
WR
RD
CS
CONVSTEOC
CLAMP 16-BIT ADC
DB4
DB15
MAX11046
CONFIGURATIONREGISTERS
INTERFACEAND
CONTROL
T/H
*Cost savings achieved by eliminating external amplifiers and level-shifting circuitry.
Power-grid monitoringFeatured products
www.maxim-ic.com/smartgrid 17
ADC simplifies firmware by capturing accurate phase and magnitude information on up to 32 channels MAX11040
TheMAX11040sigma-deltaADCoffers117dBSNR,fourdifferentialchannels,andsimultaneoussamplingthatisexpandableto32channels(i.e.,witheightMAX11040ADCsinparallel).Withaprogrammablephaseandsamplingrate,theMAX11040isidealforhigh-precision,phase-criticalmeasurementsinanoisypower-monitoringenvironment.Usingasinglecommand,theADC’sSPI™-compatibleserialinterfaceallowsdatatobereadfromallthecascadeddevices.Fourmodulatorssimultaneouslyconverteachfullydifferentialanaloginputwitha0.25kspsto64kspsprogrammabledata-outputrate.Thedeviceachieves106dBSNRat16kspsand117dBSNRat1ksps.
Benefits
• Simplifies digital interface to a microcontroller
– EightMAX11040ADCscanbedaisychainedthroughtheSPIinterface
• Easily measures a wide dynamic range– 117dBSNRat1kspsallowsuserstomeasurebothverysmallandlargeinputvoltages
• Easily measures the phase relationship between multiple input channels
– Simultaneoussamplingpreservesphaseintegritybetweencurrentandvoltagetransformersinapolyphaseenvironment
The MAX11040 can be cascaded up to 32 simultaneous channels.
REF3
SAMPLINGPHASE/FREQADJUSTMENTXTAL
OSCILLATOR2.5V
AGND
XIN
ADC
ADC
ADC
ADC
DIGITAL FILTER
AVDD DVDD
XOUT
DIGITAL FILTER
DIGITAL FILTER
DIGITAL FILTER
SYNCAIN0+AIN0-REF0
REF1
REF2
AIN1+AIN1-
AIN2+AIN2-
AIN3+AIN3-
REF
CASCINCASCOUTSPI/DSPCSSCLKDINDOUTINT
DGND
MAX11040
4-channel,fully differentialbipolar inputs
Fine/coarsesample-rateand phaseadjustment
µC
N = 1
N = 2
N = 8
SPI/DSPSERIAL
INTERFACE
Single SPI CS
Power-grid monitoringFeatured products
18 MaximSmart Grid Solutions
Benefits
• High integration saves board space – Six-channelvoltagemonitorisavailableinatiny3mmx3mmµMAXpackage
• Highly adjustable to accommodate changing design requirements
– Fixedandadjustablevoltagethresholds;adjustablethresholdmonitorsdownto0.5Vwith±1.5%accuracy
– Manual-resetandtolerance-selectinputs– Fullyspecifiedto+125°C
MAX16055
Toimprovesystemreliability,youshouldmonitorallthevoltagerailsforundervoltageconditions.Insteadofusingseparatediscretevoltagesupervisorsthatconsumevaluableboardspace,youcanuseaMAX16055ultra-smallmicroprocessorsupervisor.Thisdeviceinte-gratessixchannelsofundervoltagemonitoringintoaspace-savingµMAX®package.TheMAX16055thussignificantlyreducessystemsizeandcomponentcountwhileimprovingreliabilitycomparedtomultipleICsordiscretesupervisors.
TheMAX16055alsoincludesamanual-resetinputandatolerance-selectinputforchoosingbetween5%and10%thresholdtolerances.Themanual-resetfeatureisespeciallyversatileandpractical.Useittoforcearesetevenwhenallthevoltagerailsarewithintolerance.Itcanalsocascademultiplevoltagemonitorsorconnecttoaseparatewatchdogtimer.
TheMAX16055single-chipsolutionoffersuptoninedifferentcombinationsoffixed-voltagethresholdsandresistor-adjustablethresholds.Itisfullyspecifiedupto+125°C.
Microprocessor supervisor delivers high accuracy and reliability with reduced total cost
Block diagram of the MAX16055 6-voltage microprocessor supervisor.
IN1
IN2
IN3
IN4
IN5
IN6
TOL
RESET
MR
RESETTIMEOUT
GND
MAX16055
0.5VREFERENCE
Power-grid monitoringFeatured products
www.maxim-ic.com/smartgrid 19
Benefits
• Save cost while offering highest flexibility
– Operateover2.25Vto16Vtosupporthigh-voltageapplications
– Canbepoweredupdirectlyfromtheintermediatebus
– Usetheexternalresistor/capacitortomonitorawiderangeofpower-supplyvoltagesandprogrammabletimingdelays
MAX16052/MAX16053
TheMAX16052/MAX16053arelow-power,high-voltagemonitoringcircuitswithsequencingcapability.Eachdevicemonitorsavoltagerailwithathresholdsetbyanexternalresistor.Usingthisexternallyadjustablethreshold,theMAX16052/MAX16053monitorawidevarietyofpower-supplyvoltages.Asingleoutputwithacapacitor-programmabledelaycanbeusedtoadjustthesequencingdelaybetweenpower-supplyrails.
TheMAX16052/MAX16053areidealforuseinpower-supplysequencing,resetsequencing,andpower-switchingapplications.Thedevicesworkespeciallywellforsequencingthemultiplepowersuppliesrequiredbyhigh-performanceDSPsandothercomplexICs.InatypicalapplicationaMAX16052/MAX16053ispoweredfroma12Vsupplyrailandmonitorsapowersupplythatisderivedfromthemain12Vrail,whileturningonasecondpower-supplyrailafteraprogrammabletimedelay.
Simple reset and monitoring circuits enable easy sequencing and flexible monitoring
The MAX16052 in a typical monitoring application.
0.9V
ENABLE
1.8V
IN OUT
CDELAY
VCC
GND
3.3V
12V
Capacitor setstiming delay
Resistorsset trip
thresholds
Powered directly fromintermediate bus
MAX16052
ENABLE
IN OUT
CDELAY
VCC
GND
MAX16052
ENABLE
DC-DC
ENABLE
DC-DC
ENABLE
DC-DC
28V-tolerantopen-drain
output
Power-grid monitoringFeatured products
20 MaximSmart Grid Solutions
Benefits
• Optimize board layout– Tiny3mmx3mmTDFNpackage
• Retain calibration even during power cycling
– Nonvolatilememoryrestoresthewiperpositionduringpower-up
MAX5422/MAX5423/MAX5424
TheMAX5422/MAX5423/MAX5424nonvolatile,linear-taperdigitalpotentiometersperformthefunctionofamechanicalpotentiometer,butreplacethemechanicswithanintegratedresistorstringcontrolledwithasimple3-wire,SPI-compatibledigitalinterface.Thisdesignminimizesboardspaceandreducesinterconnectioncomplexityinmanyapplications.Eachdeviceperformsthesamefunctionasadiscretepotentiometerorvariableresistorandhas256tappoints.
Thesedigitalpotentiometersfeatureinternalnonvolatile(NV)EEPROMusedtostorethewiperpositionforinitializationduringpower-up.Thisenablesthedevicestobeusedin“dumb”applicationswherethereisnohostprocessor.The3-wireSPI-compatibleserialinterfaceallowscommunicationatdataratesupto5MHz.Thedevicesprovidethreenominalresistancevalues:50kΩ(MAX5422),100kΩ(MAX5423),or200kΩ(MAX5424).Thenominalresistortemperaturecoefficientis35ppm/°Cend-to-endandonly5ppm/°Cratiometric.
Digital potentiometers automate calibration of line-monitoring instruments
Block diagram of the MAX5422/MAX5423/MAX5424.
L
H
W
SPIINTERFACE
256-POSITIONDECODER
VDD
GND
SCLK 8-BITNV
MEMORY
8-BITLATCH
8-BITSHIFT
REGISTER
POR
8 8 256
DIN
CS
MAX5422MAX5423MAX5424
Power-grid monitoringFeatured products
www.maxim-ic.com/smartgrid 21
Benefits
• Optimize system error budget– ±0.06%(max)initialaccuracy– ±3ppm/°C(max)temperaturestability
• Save cost and valuable board area– Short-circuitprotection– Noexternalcapacitorsrequiredforstability
MAX6173–MAX6177
TheMAX6173–MAX6177arelow-noise,high-precisionvoltagereferences.Thedevicesfeatureaproprietarytemperature-coefficient,curvature-correctioncircuitandlaser-trimmedthin-filmresistorsthatresultinaverylow3ppm/°Ctemperaturecoefficientandexcellent±0.06%initialaccuracy.Atriminputallowsfinetrimmingoftheoutputvoltagewitharesistive-dividernetwork.Lowtemperaturedriftandlownoisemakethedevicesidealforusewithhigh-resolutionADCsorDACs.TheMAX6173–MAX6177acceptinputvoltagesupto40V.Thedevicesdraw320µA(typ)ofsupplycurrentandsource30mAorsink2mAofloadcurrent.Theyoperateoverthe-40°Cto+125°Cautomotivetemperaturerange.
Calibration voltage references with temperature sensor increase system precision
Block diagram of the MAX6173-MAX6177 precision voltage references.
IN
OUT
GND
*OPTIONAL
*
( VOUT + 2V) TO 40V INPUT
REFERENCEOUTPUT
MAX543650kΩPOTENTIOMETER
TRIMTEMP
MAX6173-MAX6177
22 MaximSmart Grid Solutions
Power-grid monitoringRecommended solutions
Part Description Features Benefits
Precision analog-to-digital converters (ADCs)
MAX11040 24-bit, 4-channel, simultaneous-sampling delta-sigma ADC
64ksps; internal reference; cascade to capture phase and magnitude on up to 32 channels; 117dB SNR
Minimal firmware complexity speeds time to market
MAX11044/45/46 16-bit, 4-/6-/8-channel, simultaneous-sampling SAR ADCs
3μs conversion time; 250ksps for all eight channels; 92dB SNR; -105dB THD
> 1MΩ input impedance eliminates external buffers, saving space and up to $1/channel**
MAX11054*/55*/56* 14-bit, 4-/6-/8-channel, simultaneous-sampling SAR ADCs
3μs conversion time; 250ksps for all eight channels 14-bit, pin-compatible versions of the MAX11044/45/46 make it simple to trade off resolution vs. cost
MAX1324/25/26 14-bit, 2-/4-/8-channel, simultaneous-sampling SAR ADCs
3.7μs conversion time; 250ksps for all eight channels; 77dB SNR; -86dB THD
Pin-compatible packages make it simple to design 2, 4, or 8 channels; flexibility with 0 to 5V, ±5V, or ±10V input ranges
Precision operational amplifiers
MAX9618/19/20 Ultra-low-power, zero-drift op amps Continuous self-calibration at any voltage or temperature
Save maintenance system downtime and maintain system accuracies
MAX9613/15 Low-power, autotrim op amps Self-calibration feature on startup Save maintenance system downtime and maintain system accuracies
MAX9943/44 38V, low-noise, precision op amps Excellent combination of low power (550µA) and precision (VOS of 100µV)
High-voltage precision conditioning without high power dissipation minimizes temperature errors
MAX9945 38V, CMOS-input, single op amp Excellent precision with 50fA low-input-bias characteristics
High-voltage CMOS inputs with very low bias current allow signal conditioning of high-ohmic sensors
Active filters
MAX7409/10/13/14 5th-order, switched-capacitor lowpass filters
Clock- or capacitor-adjustable corner frequency to 15kHz; 1.2mA supply current
Save space and cost by replacing discrete designs
MAX7422–25 5th-order, switched-capacitor lowpass filters
Clock- or capacitor-adjustable corner frequency to 45kHz; 3mA supply current
Save space and cost by replacing discrete designs
MAX274/75 8th-order/4th-order, 150kHz/300kHz, lowpass/bandpass filters
Resistor programmable; continuous-time filters; low noise (-89dB THD)
Save space and cost by replacing discrete designs
Calibration digital potentiometers (CDPots)
MAX5481 1024-tap (10-bit) CDPot with SPI or up/down interface
1.0µA (max) in standby; 400µA (max) during memory write
1024 taps provide very accurate calibration
MAX5477 Dual, 256-step (8-bit) CDPot with I2C interface
EEPROM write protection; single-supply (2.7V to 5.25V) operation
EEPROM protection retains calibration data so no host processor is required
MAX5427/28/29 Low-cost, one-time-programmable (OTP) digital potentiometers with up/down interface
1µA (max) standby current (no programming); 35ppm/°C end-to-end and 5ppm/°C ratiometric tempco
Increase power savings and improve measurement accuracy over temperature changes
MAX5494–99 10-bit, dual, nonvolatile voltage-dividers or variable resistors with SPI interface function as digital potentiometers
1µA (max) standby current (no programming); 35ppm/°C end-to-end and 5ppm/°C ratiometric tempco
Improve power savings and improve measurement accuracy over temperature variations
MAX5422 Single, 256-step (8-bit) CDPot with SPI interface
Tiny 3mm x 3mm TDFN package Reduces board space
(Continued on next page)
Recommended solutions
*Future product—contact the factory for availability.
**Cost savings achieved by eliminating external amplifiers and level-shifting circuitry.
www.maxim-ic.com/smartgrid 23
Power-grid monitoringRecommended solutions
Part Description Features Benefits
Calibration digital-to-analog converters (CDACs)
MAX5134–37, MAX5138/39
1-/2-/4-channel, 16-/12-bit DACs with pin-programmable zero or midscale power-up
Output set to zero or midscale upon power-up Add extra safety during power-up
MAX5661 Single-channel DAC with 16-bit voltage- or current-buffered output
Integrated high-voltage current and voltage amplifiers; serial interface
Reduces external component count; reduces cost
MAX5500 4-channel, 12-bit DAC with precision amplifier-output conditioners
Output conditioners; 0.85mA quiescent current (IQ) Needs no external amplifiers; makes equipment more cost effective
MAX5105/15 Quad, 8-bit CDACs with independent high- and low-reference inputs
Rail-to-rail output buffers; choice of I2C or SPI interface
Selectable voltage range improves granularity and prevents unsafe adjustments
MAX5106 Quad, 8-bit CDAC with independently adjustable voltage ranges
Allows customization of calibration granularity; small 5mm x 6mm package
Avoids grossly misadjusted system at the start of the calibration procedure; reduces cost of the calibration DAC by reducing the required resolution
Touch-screen controllers
MAX11800 Resistive touch-screen controller FIFO; spatial filtering; SPI interface Simplifies the task of identifying touch events
MAX11801 Resistive touch-screen controller FIFO; spatial filtering; I2C interface Simplifies the task of identifying touch events
MAX11802 Resistive touch-screen controller with SPI interface
SPI interface Basic feature set for lowest cost
MAX11803 Resistive touch-screen controller with I2C interface
I2C interface Basic feature set for lowest cost
MAX11811 Resistive touch-screen controller with haptics driver
Integrated haptics driver; I2C interface Adds tactile feedback to resistive touch screens for improved usability
UART
MAX3107 SPI/I2C UART with integrated oscillator
24Mbps (max) data rates; power-save features; RS-485 control; four GPIOs; 24-pin SSOP or small TQFN (3.5mm x 3.5mm) packages
Tiny package saves board space; high integration of features frees up microcontroller
Voltage references, calibration voltage references (CRefs), and E²CRefs
MAX6173 Precise voltage reference with temperature sensor
±0.05% (max) initial accuracy; ±3ppm/°C (max) temperature stability
Allows analog system gain trim while maintaining the digital accuracy of ADCs and DACs; allows easy system temperature compensation
MAX6220 Low-noise, precision voltage reference
8V to 40V input-voltage range; ultra-low 1.5µVP-P noise (0.1Hz to 10Hz)
Enables dependable operation during brownout
DS4303 Electronically programmable voltage reference (E²CRef)
Wide, adjustable output-voltage range can be set within 300mV of the supply rails with ±1mV accuracy
Automates production test through easy calibration for reference voltages from 0.3V to 2.7V
(Continued on next page)
Recommended solutions (continued)
24 MaximSmart Grid Solutions
Power-grid monitoringRecommended solutions
Recommended solutions (continued)
Part Description Features Benefits
Voltage supervisors
MAX16052/53 High-voltage, adjustable sequencing/supervisory ICs
2.25V to 16V supply range; adjustable voltage thresholds and reset timeout
High-voltage input reduces costs; adjustable voltage thresholds increase flexibility
MAX6746–53 Capacitor-adjustable watchdog timer and reset ICs
Capacitor-adjustable timing; 3μA supply current Versatile for easy design reuse; save space in small modules
MAX6715–29, MAX6730–35
1-/2-/3-voltage µP supervisory circuits with independent watchdog output
Multiple fixed and one adjustable thresholds A single multivoltage IC increases reliability and saves board space by replacing multiple devices
MAX16000–07, MAX16008/09
Low-voltage, 4-/6-/8-voltage µP supervisors in TQFN package
±1.5% accuracy; integrated watchdog timer; manual-reset and margin-disable inputs
Improve reliability; simplify design and lower the overall system cost; reduce board space
MAX16055 Ultra-small, 6-voltage µP supervisor Low 35µA supply current; fully specified up to +125°C
Increases reliability; saves power; reduces total solution size and cost
Power supplies
MAX15023/26 Low-cost, small, DC-DC synchronous buck controllers (dual/single)
Versatile operation from 4.5V to 28V; suitable for multiple applications
Save space and cost
MAX15046 40V, high-performance, synchronous buck controller
4.5V to 40V input-voltage range; adjustable outputs from (0.85 x VIN) down to 0.6V; 100kHz to 1MHz switching frequency
Versatile for easy design reuse; saves space in small modules
Real-time clocks (RTCs) with NV RAM
DS1747 RTC with 512k x 8 NV SRAM Integrated NV SRAM, RTC, crystal, power-fail control circuit, lithium energy source
Saves space and cost by integrating NV memory and RTC; retains data during power outage
DS17285/87, DS17485/87, DS17885/87
3V/5V RTCs RTC/calendar; one time-of-day alarm; three maskable interrupts with a common interrupt output; programmable square wave; 2KB to 8KB of battery-backed NV SRAM
Save space and cost by integrating memory and RTC; retain clock data during power outage
Temperature sensors
DS7505 Low-voltage digital thermometer and thermostat
±0.5°C accuracy from 0°C to +70°C; 1.7V to 3.7V operation; industry-standard pinout
Industry-standard pinout allows easy accuracy upgrade and supply-voltage reduction from LM75
DS18B20 1-Wire® digital temperature sensor ±0.5°C accuracy; 1-Wire interface; 64-bit lasered ID code
1-Wire interface and 64-bit ID code allow multiple distributed precision sensors on a single bus
MAX6603 Dual-channel platinum RTD interface Two input channels for PT200 RTDs; analog outputs; ±5kV ESD protection
Saves space and cost
For a list of Maxim's recommended power-grid monitoring solutions, please go to: www.maxim-ic.com/grid-monitoring.
www.maxim-ic.com/smartgrid 25
CommunicationsOverview
Communications
OverviewAnelectricitygridwithoutadequatecommunicationsissimplyapower“broadcaster.”Itisthroughtheadditionoftwo-waycommunicationsthatthepowergridismade“smart.”
Communicationsenablesutilitiestoachievethreekeyobjectives:intel-ligentmonitoring,security,andloadbalancing.Usingtwo-waycommuni-cations,datacanbecollectedfromsensorsandmeterslocatedthrough-outthegridandtransmitteddirectlytothegridoperator’scontrolroom.Thisaddedcommunicationscapabil-ityprovidesenoughbandwidthforthecontrolroomoperatortoactivelymanagethegrid.
Thecommunicationsmustbereliable,secure,andlowcost.Thesheerscaleoftheelectricalgridnetworkmakescostacriticalconsiderationwhenimplementingacommunicationstechnology.Selectingasolutionthatminimizes
thenumberofmodemsandconcen-tratorsneededtocovertheentiresystemcandramaticallyreduceinfra-structurecosts.Atthesametime,theselectedtechnologymusthaveenoughbandwidthtohandlealldatatrafficbeingsentinbothdirectionsoverthegridnetwork.
Communications networks and protocolsCommunicationsinthesmartgridcanbebrokenintothreesegments.
Wide area network (WAN)coverslong-hauldistancesfromthecommandcentertolocalneighbor-hoodsdownstream.
Neighborhood area network (NAN)managesallinformationbetweentheWANandthehomeareanetworkusingmedium-voltagelines.
Home area network(HAN)extendscommunicationtoendpointswithintheend-userhomeorbusiness.
Eachsegmentisinterconnectedthroughanodeorgateway:aconcentratorbetweentheWANandNANandane-meterbetweentheNANandHAN.Eachofthesenodescommunicatesthroughthenetworkwithadjacentnodes.Theconcentratoraggregatesthedatafromthemetersandsendsthatinformationtothegridoperator.Thee-metercollectsthepower-usagedataofthehomeorbusinessbycommunicatingwiththehomenetworkgatewayorfunctioningasthegatewayitself.
Eachsegmentcanutilizedifferentcommunicationstechnologiesandprotocolsdependingonthetrans-missionenvironmentsandamountofdatabeingtransmitted.Inadditiontothearchitecturechoicebetweenwirelessandpowerlinecommunica-tions(PLC),thereareavarietyofwirelessandPLCprotocolstochooseamong(Table 1).
MAXIMSOLUTION
DOWN-CONVERTER
ADC
ADC
DAC
DAC
COMPLETE RF TRANSCEIVER
UP- DRIVER
LNA
CONVERTER
SW
MODEM
POWERLINECOMMUNICATIONS
OUTBOUNDINBOUND
MULTIPROTOCOL
TRANSFORMER DRIVER
RS-232
DC-DC
ANTENNAANTENNA
AC LINE
OTHERMETERS
PA
RS-485
SERIAL
WIRELESS
DOWN-CONVERTER
ADC
ADC
DAC
DAC
COMPLETE RF TRANSCEIVER
UP-DRIVER
LNA
CONVERTER
SW
DC-DCPA
WIRELESS
MODEM
POWERLINECOMMUNICATIONSAC LINE
DC-DC DC-DC
Maxim offers solutions for powerline, wireless, and serial communications. For a list of Maxim's recommended solutions, please go to: www.maxim-ic.com/communications.
26 MaximSmart Grid Solutions
CommunicationsOverview
TheWANisthecommunicationspathbetweenthegridoperatorandtheconcentrator.TheWANcanbeimple-mentedoverfiberorwirelessmediausingEthernetorcellularprotocols,respectively.CellularorWiMAX®ismostcommonlyusedbetweenthegridoperatorandtheconcentrator.
TheNANisthepathbetweentheconcentratorandthemeter.ItuseseitherwirelessorPLC.Typically,theconcentratorcommunicateswithanywherefromafewtohundredsofmeters,dependingonthegridtopologyandthecommunica-tionsprotocolused.Today,thereisnostandardforthisportionof
thenetwork,somostimplementa-tionsuseproprietarywirelessorPLCtechnologies.SeveralstandardsbodiesarecurrentlyworkingwithutilitiesandtechnologyproviderstodefinestandardsforwirelessandPLCprotocols.TheIEEE802.15.4gstandardtargetswireless;theIEEEP1901,OPENmeter,andITU-TG.hnemstandardsarebeingdevelopedforPLC(Table 2).
TheHANisusedbyutilitiestoextendthereachoftheircommunicationpathtodevicesinsidethehome.Thisnetworkcansupportfunctionssuchascyclingairconditionersoffduringpeakloadconditions,sharing
consumptiondatawithin-homedisplays,orenablingacard-activatedprepaymentscheme.Thearrivalofelectric/plug-inhybridelectricvehicles(EV/PHEVs)presentsaspecialcommunicationsscenarioforHANs.StandardsbodiesaredefiningPLCprotocolsforcommunicatingwithvehiclechargingsystems.
Inadditiontosupportingthedatarequirementsforsmartgridactivities,aHANmightalsoinclude:peer-to-peer(P2P)communicationsbetweendevicesinsidethehome;communica-tionswithhandheldremote-controldevices,lightingcontrols,andgasorwatermeters;aswellasbroadband
Table 1: Smart grid communications protocols
Network Protocol Advantages Disadvantages Recommendation
WAN Wireless (2G/3G/LTE cellular, GPRS)
Extensive cellular infrastructure is readily available; large amount of aggregated data can be communicated over a long haul
Utility must rent the infrastructure from a cellular carrier for a monthly access fee; utility does not own infrastructure
Wireless usually works best
NAN Wireless ISM Long range; leaps transformers Currently proprietary; dead spots complicate installation and maintenance
Useful in some topologies, such as in the U.S.
IEEE® 802.15.4g Long range; leaps transformers Not yet an accepted standard Useful in some topologies
ZigBee® Low cost; low power consumption allows battery operation; well-known standard
Low data rate; very short range; does not penetrate structures well
Unlikely to be used in NANs
First-generation PLC (FSK, Yitran, Echelon®)
Low cost Unreliable; low bandwidth Bandwidth and reliability inadequate for the smart grid
Early-generation narrowband OFDM
Better range, bandwidth, and reliability than FSK
Does not cross transformers; does not coexist with first-generation PLC
Not recommended for new designs due to cost and compatibility concerns
Broadband PLC High data rate Does not cross transformers Increases infrastructure cost, making it too costly for most large-scale deployments
G3-PLC Highly reliable long-range transmission; crosses transformers, reducing infrastructure costs; data rate supports frequent two-way communications; coexists with FSK; open standard; supports IPv6
Not yet an accepted standard Excellent for NAN worldwide
HAN ZigBee Well-known standard that offers low cost and low power
Very short range; does not penetrate structures well
Well suited for communication between water and gas meters
Wi-Fi® Popular technology with high data rates Medium range; does not penetrate cement buildings or basements
Good for consumer applications, but no provisions for meeting utility objectives
First-generation PLC (FSK, Yitran, Echelon)
Low cost Not reliable in home environments Unlikely to be used in homes due to high levels of interference
Early-generation narrowband OFDM
Better range, bandwidth, and reliability than FSK
Does not cross transformers; does not coexist with first-generation PLC
Not recommended for new designs due to cost and compatibility concerns
Broadband PLC High bandwidth Short range is not sufficient for NAN Good for consumer applications, but no provisions for meeting utility objectives
G3-PLC Highly reliable; sufficient data rate; IPv6 enables networking with many devices
Not yet an accepted standard Excellent for HAN worldwide
www.maxim-ic.com/smartgrid 27
CommunicationsOverview
Table 2: Communication protocols under consideration around the world
Region WAN NAN HAN
North America Cellular, WiMAX G3-PLC, HomePlug®, IEEE 802.15.4g, IEEE P1901, ITU-T G.hnem, proprietary wireless, Wi-Fi
G3-PLC, HomePlug, ITU-T G.hn, Wi-Fi, ZigBee, Z-Wave
Europe Cellular G3-PLC, IEEE P1901, ITU-T G.hnem, PRIME, Wi-Fi G3-PLC, HomePlug, ITU-T G.hn, Wi-Fi, Wireless M-Bus, ZigBee
China Cellular, band-translated WiMAX
G3-PLC, RS-485, wireless to be determined G3-PLC, RS-485, Wi-Fi, to be determined
Rest of the World Cellular, WiMAX G3-PLC, HomePlug, IEEE 802.15.4g, IEEE P1901, ITU-T G.hnem, PRIME, RS-485, Wi-Fi
G3-PLC, HomePlug, ITU-T G.hn, RS-485, Wi-Fi, Wireless M-Bus, ZigBee, Z-Wave
The smart grid communications architecture.
WAN
NETWORKOPERATING
CENTER
SMART GRIDNETWORK SMART HOME
OUTSIDE THE WALL INSIDE THE WALL
NAN HAN
WANEthernetCDMAGSM
CONCENTRATOR
RELAY
CAP BANK/E-BRIDGE
NETWORKMANAGEMENT
SYSTEMS
SWITCH/S-BRIDGE
ELECTRICITYMETER
00000
00000
00000
00000
00000
GASMETER
00000000
00000000
28 MaximSmart Grid Solutions
CommunicationsOverview
traffic.ProtocolssuchasRS-485,ZigBee,Z-Wave®,andHomePlugareusedforthisnetwork.Ifthereisaseparatehomegateway,itispossiblethatadditionalprotocolscouldbeusedtocommunicatewithappliances,thermostats,andotherdevices.
CommunicationsalternativesintheHANcanoftencoexist,bututilitysupportwillprobablybelimitedtotechnologiesneededtosupporttheutility'sprimaryobjectives.
RF communicationsWirelesscommunicationsisusedinsomeareasforautomatedmeterreading(AMR).Severalproprietaryandstandardizedwirelessprotocolsareavailabletoday.Frequencybandsofinterestrangefrom200MHzto3.9GHz.
SeveralblocksareusedtoimplementRFcommunications(Figure 3).Thesignalisreceivedthroughanantennaandgoesthroughabandpassfilter,whichrejectsfrequenciesbeyondtheoneofinterest.Thesignalisthenswitchedtothereceivesignalchain,whereoneormoredownconverterstranslatefromthecarrierfrequencytoanintermediatefrequency(IF),thentothein-phase/quadrature-phase(I/Q)stage,andthentothebaseband.
MorerecentarchitectureseliminateoneormoreoftheIFdownconver-sionstageswithalow-IForzero-IFsamplingarchitecture.ThesedesignsuseeitherasingleADCtodigitizeahigh-orlow-IFsignalor,typically,twoADCstodigitizeacomplexI/Qbasebandsignal.TheADCoutputisfedintoaDSPordigitalASICwherethebasebandisprocessed.Sometimesamicroprocessorisalsousedtohandlethehigherlayersoftheprotocol.Fortransmission,theprocessingpathandsignalchainarereversed,andthesignalissentouttotheantenna.
Thesystemcanbepartitionedinseveralways.ZigBeeorMaxim’sSimplelinkradios,forinstance,can
provideacompletesystem-on-chip(SoC)solution.Inothercases,suchasproprietaryprotocols,adigitalASICandanRFtransceiverareusedtobuildthecompleteradiolink.MaximhasbothstandardRFtransceiversaswellascustomASICsthatcanbeconfiguredastransceivers.
Powerline communications
Overview of modulation schemes
PowerlinecommunicationsusesACpowerlinesasthetransmissionmedium.Somesystems,suchasMaxim’s,workoverDCandcoldwiresaswell.Thereareseveralpowerlineprotocolsinthemarkettoday.Theseprotocolsbreakdownintooneoftwobasicmodulationschemes:frequency-shiftkeying(FSK)andorthogonalfrequency-divisionmulti-plexing(OFDM).
FSKisanoldermodulationschemethathasbeenusedbytheutilityindustryinthepastforrudimen-tarypurposes,suchasinfrequentone-waycommunicationsfrommeterstoaconcentrator.However,FSKsuffersfromasignificantdrawback:ifaninterferercoincideswithoneofthetransmitfrequen-cies,thereceiverlosesreception.AsFSKonlyswitchesbetweentwofrequencies,bandwidthisnotusedefficiently,resultinginlowdatarates.Thislowdatarateisinsufficientforsmartgridapplicationsthatdemandbidirectionalcontrol.
Real-worldPLCrolloutsfrequentlyrequireuptoseveralhundredmeterstobeconnectedtoasingledataconcentratoroverthemedium-voltage(MV)portionofthenetwork.Thisrequiresdatacommunicationacrosslow-voltage/medium-voltage(LV/MV)transformers.Sincethesetransformerscancauseseveraltensofdecibelsof(frequency-selective)signalattenuationtoFSKsignals,moreadvancedandrobustcommunicationmethodsthanFSKareneeded.
OFDMhasbeenusedinmanymoderncommunicationsystemssuchasdigitalradioandTV,Wi-Fi,andWiMAX,aswellasearly-gener-ationnarrowbandprotocolssuchasPRIME.Today,OFDMtechnologyisenablingexcitingnewfunctionsandcapabilitiesforPLCnetworks.Amongthemostsignificantbenefits,itgivestheutilityindustrythebandwidthneededtobuildintelligenceintothepowergridwhilemeetingaggressivecosttargets.
Advancements offered by G3-PLC technology
G3-PLCemploysOFDMtooptimizebandwidthutilization.SinceOFDMusesmultiplecarrierstotransmitdata,interferenceataspecificfrequencyorfrequency-selectiveattenuationcannoweffectivelybeeliminated.Inadditiontoincreasedreliability,thiscapabilityallowsconsiderablymoredatatobesent.
Additionally,OFDM’sspectraleffi-ciencyallowstheuseofadvancedchannel-codingtechniques.InMaxim’spowerlinesolutions,advancedchannelcodingisusedalongwithOFDMtomaximizecommunicationrobustnessinadversechannelconditions.Twolayersoferror-correctioncoding(convolutionalandReedSolomon)areusedtoensurereliabledatatransmission.Inaddition,dataisinterleavedinbothtimeandfrequencydomainsacrossOFDMcarrierstodecreasethesensitivitytoimpulsenoiseandprotectagainstbursterrors.
Maxim’snext-generationG3-PLCtechnologyincludesadditionalcapabilities:
• MAC-levelsecurityusinganAES-128cryptographicengine
• Meshroutingprotocoltodeterminethebestpathbetweenremotenetworknodes
www.maxim-ic.com/smartgrid 29
CommunicationsOverview
• Adaptivetonemappingforoptimalbandwidthutilization
• Arobustmodeofoperationtoimprovecommunicationundernoisychannelconditions
• Channelestimationtoselecttheoptimalmodulationschemebetweenneighboringnodes
• CoexistencewitholderS-FSKsystems
G3-PLCissorobustthattransmissionacrosstransformersisachievablewithaninexpensivecoupler.Thisreducesthenumberofconcentratorsneededinsmartgridinstallations,savingsystemimplementationcostandmakingPLCcostcompetitivewith,orevensuperiorto,wirelessadvancedmeterinfrastructure(AMI)systems.Distancesupto6kmhavebeenachievedonlow-andmedium-voltagelines,allowingremotesitestobemonitoredaswell.ThecompleteG3-PLCprofilespecification,aswellasspecificationsforthePHYandMAClayers,canbedownloadedfrom:www.maxim-ic.com/G3-PLC.
Maximprovidesbothhigh-frequencyandlow-frequencyPLCchipsetsforsmartgridapplications.Maximrecommendsusingnarrow-bandOFDMtotransmitdatainaspectrumconsistentwithworld-widespectralpower-densitystandardsforPLC(below~500kHzinCENELEC®,FCC,andARIB).
Serial communications
Achieve long cable runs in noisy environments
Inharshandnoisyenvironments,suchasmulti-unitresidentialbuildingsorindustrialsettings,anRS-485busarchitecturecanbeusedtoimplementalow-cost,yetrobust
communicationsnetwork.Thediffer-entialnatureofRS-485signalingmakesitlesssusceptibletoexternalinterference.Moreover,theRS-485specificationsupportsmultidropconfigurations,thusallowingtheconnectionofmultiplemeterstoasinglebus.
Forinstance,RS-485canbeusedinanapartmentbuildingtotransmitdatafrommetersineachapartmenttoacentralunitthataggregatesthedatafromtheindividualmeters,whichcanthenbereadthroughawirelessorPLClink.Asimilarapproachcanbeusedinindustrialsystemsthatrequiremultiplecostcenterstobemetered.
Selecting an RS-485 transceiver
Tomaintainsignalqualityoverlongcablelengthsthroughnoisyenvi-ronments,designersshouldlookfortransceiverswiththefollowingfeatures.
ESD protectiontopreventdamagefromhandlingandconnectionofthetransceivers.
Fail-safe circuitrytoprotectthedesignfromopen-andshort-circuitconditions.
Slew-rate limitingtoreduceradiatedemissionsanddataerrors.
Hot-swap capabilitytoeliminatefalsetransitionsonthebusduringpower-uporliveinsertionofthetransceiver.
Isolation toprotectagainstvoltagespikes,groundloops,electricalstorms,etc.
AutoDirection controltosaveanoptocouplerbyeliminatingtheneedforanisolatedcontrolchannel.
±80V fault protection toeliminatetheneedforexternalcomponentssuchaspolyswitchlimitersandzenerdiodes.
Add a point-to-point link with RS-232 transceivers
TheRS-232protocolisintendedforshort-distancecommunica-tionbetweentwodevices.MeterdesignerstypicallyuseRS-232forimplementingapoint-to-pointlinkbetweenautilitymeterandacomputer,remotedisplay,ormodem.
BecausetheRS-232portisonlyusedafractionofthetime,itshouldincludeautomaticshutdowncircuitrytoconservepower.Additionally,designersshouldlookfordeviceswithextendedESDprotectiontopreventdamageduringhandling.
Maxim’sRS-232familycombinesproprietaryAutoShutdown™technol-ogywithrobustESDprotection,fastdatarates,andsmallfootprints—basically,everythingthatyouneedinanRS-232transceiver.
Multiprotocol transceivers provide design flexibility
Incaseswheretheprotocolsareeithernotknowninadvanceorwherethereneedstobeflexibility,Maxim’smultiprotocoltransceiversallowyoutouseasingleboardlayouttosupporteitherRS-232orRS-485communication.Thissavestimebecauseonedesigncansupportdifferentmarketrequire-ments,andeachboardcansimplybeprogrammedtothedesiredprotocolduringproduction.
30 MaximSmart Grid Solutions
CommunicationsFeatured products
Benefits
• Robust long-distance transmission– Upto100kbpsdatarateat10kHzto490kHz;32kbpsat10kHzto95kHz
– Built-inAGCwith62dBdynamicrangeandDCoffsetcancellation
– Includesforwarderrorcorrection(FEC),CRC16,andCRC32
– CSMA/CAcontrolstrafficinmultinodenetworks
– ARQenhancesdatatransmissionreliability
• High integration lowers BOM cost and speeds design
– On-chipband-selectfilter,VGA,and10-bitADCfortheRxpath
– On-chipband-waveform-shapingfilter,programmablepredriver,and10-bitDACfortheTxpath
• Built-in security protocols prevent tampering
– FastDES/3DESengine
MAX2990/MAX2991 (G3-PLC Lite)
TheMAX2990modemandtheMAX2991analogfront-end(AFE)compriseaPLCchipsetthatachievesreliablelong-rangedatacommunications.TheMAX2990isahighlyintegratedSoCthatcombinesthePHYandMAClayersusingMaxim’s16-bitMAXQ®microcontrollercore.TheMAX2991isastate-of-the-art,stand-aloneICthatfeaturestwo-stageautomaticgaincontrol(AGC)witha62dBdynamicrangeandon-chipprogrammablefilters.BothdevicesoperateintheCENELEC,FCC,andARIBfrequencybands.
OFDM-based PLC chipset dramatically improves reliability and network data rate
Block diagrams of the MAX2990 and MAX2991.
I2C
GPIO
SPITMMCU (MAXQ)
UART
WATCHDOGTIMER
TIMER/PWM
FLASH32KB
ROM5KB x 8
SRAM4KB
DUAL-PORTSRAM
4KB x 8
JTAG RTC
DESENGINE CRC32
PLC MAC
INTERRUPTCONTROLMAX2990 OFDM PLC PHY
JAMMERCANCELLERAND SYNC
REED-SOLOMON
VITERBIDECODER
FFTBPSK
DEMOD
REED-SOLOMON
CONVOLUTIONALENCODER
INSERTPREAMBLE
AND CYCLICPREFIX
IFFT
CSMA/ARQ
MAX2991
AFE
SPI I
NTER
FACE
TRANSMITTER PATH
RECEIVER PATH
LPF
ADAPTATION 2ADAPTATION 1
HPFLPF
DAC
ADC
SERI
AL IN
TERF
ACE
PROCESS TUNING BLOCK CONTROL REGISTERS
VGA1 VGA2
IIRFILTERPREDRIVER
CommunicationsFeatured products
www.maxim-ic.com/smartgrid 31
Next-generation OFDM-based PLC modem improves network reliability and coverage over earlier generationsMAX2992* (G3-PLC)
TheMAX2992modemimproveslong-rangedatacommunicationsbyextendingnetworkcapabilitiestotransmissionovertransform-ers.ThishighlyintegratedSoCcombinesthePHYandMAClayersusingMaxim’s32-bitMAXQmicrocontrollercore.TwoformsofFECareaddedtofurtherimprovecommunicationreliabilityoverearliergenerationsandaddbackwardscompatibilitywitholderFSK-basedPLCtechnologies.ThisdeviceoperatesintheCENELEC,FCC,andARIBfrequencybands.WhencombinedwiththeMAX2991,afullPLCmodemcanberealized.
Benefits
• Reliable long-distance transmission– Upto225kbpseffectivedatarateat10kHzto490kHz;44kbpseffectivedatarateat10kHzto95kHzwithamaximumdatarateof298kbps
– Adaptivetonemappingmonitorssub-channelconditionsandautomaticallyselectstheoptimaltransmissionparameters
– FEC,CRC16,andCRC32– CSMA/CAcontrolstrafficinmultinodenetworks
– ARQenhancesdatatransmissionreliability
– FastAES-128engineforhighdatasecurity
• Reduces system cost– Long-distance(6km)transmissionmeansfewerrepeaters
– Communicationacrosstransformersrequiresfewerdataconcentrators
– BackwardscompatibilitywithFSK-basedsolutionsimprovesinteroperability
• Full IPv6 addressing extends system addressability all the way into the home
– Implements6LoWPANadaptationlayersupportingIPv6
Block diagram of the MAX2992.
TIMERS1 TO 7PMEM
128KB x 8ROM
6KB x 8SRAM FOR
DATA128KB x 8DUAL RAM
4KB x 8
JTAG
UART1
WD
UART0
SPI0
SPI1
SSSC
LK
MIS
IM
ISC
BUFFER MANAGER
MAXQ30µC
GPIO
FAST COPYINTERRUPTCONTROL
128KBFLASH
WATCHDOGTIMER
1.2REGULATOR
Tx DATAMANAGER
TxBUFFER
G3 PHY
TRANSMITTER
RECEIVER
FFT
RxBUFFER
Rx DATAMANAGER
AESENCRYPTION
CRC32 MAX2992*
AFEINTERFACE
HF OSC
*Future product—contact the factory for availability.
CommunicationsFeatured products
32 MaximSmart Grid Solutions
Benefits
• Transceivers support industry standards for easier, faster design
– SupportfortheIEEE802.11b/gstandardstoleveragealargeecosystemofHANdevices
• Low noise and high sensitivity enable larger networks
– Lownoisefigure(2.6dB)andreceivesensitivity(-76dBm)enablethelongestrange
• On-chip filters eliminate external SAW filter and reduce BOM count and cost
– IntegratedPAwith+18.5dBmtransmitpowerreducesBOMcountandPCBarea
MAX2830/MAX2831/MAX2832
TheMAX2830/MAX2831/MAX2832Wi-FiRFtransceiverssupportwirelesscommunicationstandardsintheunlicensed2.4GHzfrequencyband.Maxim’slineofWi-Fiproductsaredirect-conversion,zero-IFOFDMtransceiversprovidingbest-in-classperformancetosupportthelongestdistances.Customfrequencybandsfornonstan-dardandmultimodeapplicationsarealsoavailable.
Wi-Fi transceivers enable communication over the longest distances
Block diagram of Maxim’s Wi-Fi transceivers.
PLL
OSC
0°90°Wi-Fi
TRANSCEIVER
CommunicationsFeatured products
www.maxim-ic.com/smartgrid 33
Benefits
• Best-in-class performance extends link range
– Lowestnoisefigure(2.3dB)provideslongestrange—18%fartherthanclosestcompetitor
• Smallest WiMAX transceiver fits the tightest designs
– Tiny3.6mmx5.1mmwafer-levelpackage(MAX2839AS)
• Complete frequency coverage with MIMO support to reach customers worldwide
– 2.3GHzto2.7GHzwith1x2MIMOsupport(MAX2839)
– 3.3GHzto3.9GHzwith2x2MIMOsupport(MAX2842)
MAX2839/MAX2842
TheMAX2839/MAX2842WiMAXRFtransceiversprovidetheflex-ibilitytosupportwirelesscommunicationstandardsinthelicensed2GHzand3GHzfrequencybands.Maxim’sWiMAXproductsaredirect-conversion,zero-IF,MIMOOFDMtransceiversthatuseadual-receiverarchitecturetomaximizedatathroughputandlinkrange.Customfrequencybandsfornonstandardandmultimodeapplica-tionsarealsoavailable.
WiMAX transceivers boost range and throughput for faster data access
Block diagram of Maxim’ s WiMAX transceivers.
PLL
OSC
0°90°WiMAX
TRANSCEIVER
CommunicationsFeatured products
34 MaximSmart Grid Solutions
Benefits
• Extends battery life– Lowactive(<7mARx,<12mATx)andshutdown(<1µA)currentextendsbatterylife
– Programmablereceivershutdown/wake-upcycleforadditionalcurrentsavings
• Compact radio module for space- constrained metering applications
– Small5mmx5mmTQFNpackage
• Good penetration in buildings
MAX7032
TheMAX7032transceiveroffersaninexpensive,low-powersolutionforone-wayandtwo-wayreportingfrommetersinHANsandsomeNANs.Thetransceiverusesthelicense-freelow-frequencyradiobandsintheU.S.(260MHzto470MHz)andEurope(433.05MHzto434.79MHz).Theradio’ssimpleASKorFSKmodulationtechnique,outstandingsensitivity,wideselectionofdatarates,andlowcurrentdrainmakeittheperfectchoiceforlocalradiolinksandnetworksinthesefrequencyranges.Thetransceivercanachievelinkmarginsbetterthan120dB,whichmeansthatitcanreach1kmoveropenflatterrainormaintainalinkbetweenanundergroundwatermeterandalocalconcentrator.TheMAX7032isflexibleenoughtoworkwithmultiplesmartgridcommunicationstandards.
260MHz to 470MHz ISM radio for HANs and NANs extends battery life up to seven years
System diagram for the MAX7032.
µP
METER OR READER KEYPAD/CONTROLLER
CRYSTAL
CERAMIC IF FILTER
PAOUT
LNAIN
TX/RX1
SCLK CSBDIO
DATA
LNASRC4 Ls4 Cs
LNAOUT
VDD
VDD
HVIN
AVDD
DVDD
SUPPLY, BYPASS
DATA FILTER AND DETECTOR
2 Rs4 Cs
METER SENSOR (WATER OR GAS VOLUME, FLOW, ETC.)
METER OR READER DISPLAY
ANTENNA MATCHING NETWORK
MAX7032TRANSCEIVER
CommunicationsFeatured products
www.maxim-ic.com/smartgrid 35
Benefits
• Extends battery life – Lowactive(<35mA)andshutdown(<0.5µA)currentconservesbatterylife
• Low BOM cost– Onlycrystalandmatchingcomponentsareneeded
• Good penetration in buildings – MaximumallowableTxpower(25mW)forEuropeanETSIstandard
MAX7049*
TheMAX7049ASK/FSKtransmitteroffersaninexpensive,low-powersolutionforone-wayreportingfrommetersinHANsandsomeNANs.Thetransmitterusesthelicense-freelow-andhigh-frequencybandsintheU.S.andEurope,makingitaveryflexiblesolution.TheshapedASKorFSKmodulationtechniquereducesthetransmittedfrequencybandwidthsothatmorefrequencychannelscanbeused.Thewideselectionofdataratesandlowcurrentdrainmakeitwellsuitedforlocalradiolinksandnetworks.ThisICisflexibleenoughtoworkwithmultiplesmartgridcommunicationstandardsandiscompatiblewithmodesSandToftheEuropeanM-Busstandard.
Low-/high-band transmitter for HANs/NANs extends battery life up to seven years
System diagram for the MAX7049.
µP
METER OR READER KEYPAD/CONTROLLER
CRYSTAL
PLL FILTER
PA+
PA-
SDOHOP ENABLE CSBSDISCLK
DATAIN
CPVDD4 Ls4 Cs
CRTL CPOUT
VDD
VDD
AVDD
DVDD
SUPPLY, BYPASS
1 R2 Cs
METER SENSOR (WATER OR GAS VOLUME, FLOW, ETC.)
METER OR READER DISPLAY
ANTENNA MATCHING NETWORK
MAX7049*TRANSCEIVER
*Future product—contact the factory for availability.
CommunicationsFeatured products
36 MaximSmart Grid Solutions
ASIC Services
Maxim’sASICservicesareavailabletomeetyourspecificapplicationrequirements.Maximoffersflexibleengagementoptionsfromfoundrysalesthroughturnkeydesigntojoint-developmentprojects.Oursmartgridsolutionsinclude:
• Wireless backhaul; distribution asset management– WiMAXandrebandedWiMAXtransceivers
• AMR; fault diagnostics– FSK,ASK,OFDM,DSSStransceivers
• AMI– WiFi,ZigBee/802.15.4transceivers
• Proprietary solutions– 400MHzto5GHzRF/wirelesstransceivers
RF expertise to deliver custom-tailored solutions for your specific smart grid needs
Benefits
• Maxim’s expertise gives you a high first-silicon success rate
– Over15yearsofexperienceintheASICbusiness
– RichanalogandRFIPcatalogspeedsyourtimetomarket
• In-house process technologies provide optimal performance-cost tradeoff
www.maxim-ic.com/ASICs
CommunicationsFeatured products
www.maxim-ic.com/smartgrid 37
Benefits
• Provide adaptability without additional parts or design work
– Pin-programmablehalf-orfull-duplexcommunication
– Pin-selectableRS-232orRS-485/RS-422operation
• Save board space and cost– Integrated±15kVESDprotectioneliminatesexternalprotectioncircuitry
– Allowupto256transceiversonthebuswithoutrequiringanextraserialbus,UART,ormicroprocessor
• Reduce power consumption– First3Vmultiprotocolsolutionintheindustry
– 5xlowersupplycurrentthanthecompetition—significantlyreducespowerdissipation
MAX3160E/MAX3161E/MAX3162E
TheMAX3160E/MAX3161E/MAX3162EaremultiprotocoltransceiversthatallowdesignerstouseasingledevicetosupportbothRS-232andRS-485serialcommunicationsinpower-meterapplications.Thesedevicesofferflexibilityandconveniencethroughapin-selectableinterface,whichmakesiteasytoprogrameachboardtothedesiredprotocolduringproduction.Inaddition,thetransceivershaveextraprotectionagainststaticelectricity;truefail-safecircuitrythatguaranteesalogic-highreceiveroutputwhenthereceiverinputsareopenorshorted;a10nAshutdownmode;short-circuitlimiting;andthermalshutdowncircuitrytoprotectagainstexcessivepowerdissipation.
Multiprotocol transceivers enable on-the-fly protocol selection for power-meter communications
Block diagram of Maxim’s multiprotocol transceivers.
RS-232
RS-485/RS-422
UART
MAX3160E
DUAL CHARGEPUMP
CONTROLLOGIC
LOGICI/O
MULTI-PROTOCOL
TRANSCEIVERBLOCK
CommunicationsFeatured products
38 MaximSmart Grid Solutions
Benefits
• AutoDirection control saves cost and board space
– Reducesthenumberofopticalisolatorsneededinisolatedapplications
• Built-in LDO offers convenience without the worry of providing a regulated voltage level
– Operatesfromanunregulated6Vto28Vpowersupplyandprovides5V/20mAofpowertoexternalcircuits
• Extended ESD level of ±15kV (Human Body Model) eliminates external ESD protection circuitry
• 1/8-unit load receiver input impedance enables up to 256 peripheral sensors in the system
MAX13412E/MAX13413E
TheMAX13412E/MAX13413Earehalf-duplexRS-485/RS-422transceiversoptimizedforisolatedpowermeters.Thesedevicesreducedesigncomplexitybyintegratingalow-dropoutregulator(LDO)andasensingcircuitforAutoDirectioncontrol.TheinternalLDOallowsthedevicestooperatefromawide,unregulatedvoltagerange(6Vto28V),simplifyingpower-supplydesigns.AutoDirectioncontrolreducescostandboardspacebyeliminatinganoptocouplerinisolatedpower-meterapplications.OtherfeaturesincludeenhancedESDprotection,fail-safecircuitry,slew-ratelimiting,andfull-speedoperation.
Highly integrated RS-485 transceivers simplify power-meter interface designs
VREG
MCU AND RELATEDCIRCUITRY
UNREGULATED ISOLATEDPOWER SUPPLY
(6V TO 28V)
MAX13412E/MAX13413E
LDO
DGND
RE
A
B
DI
VCC
VREG
VSYS
VSYS
DETECTCIRCUIT
RO
Integrated LDO allows wide supply range
(6V to 28V)
5V output VREGsupplies up to 20mAto external circuitry
R
AutoDirection controleliminates third
optocoupler
System block diagram of the MAX13412E/MAX13413E.
www.maxim-ic.com/smartgrid 39
CommunicationsRecommended solutions
Part Description Features Benefits
RF transceivers
MAX2830/31/32 Direct-conversion, zero-IF RF transceivers for 2.4GHz 802.11g/b
Integrated PA, antenna diversity switch, and crystal oscillator; best-in-class receive sensitivity (-76dBm)
Low-cost, low-BOM implementation for 802.11b/g standards
MAX2839 Direct-conversion, zero-IF RF transceiver for 2.3GHz to 2.7GHz MIMO WiMAX
1x2 MIMO RF transceiver with best-in-class noise figure (2.3dB) and linearity specifications; 8mm x 8mm TQFN package
Best-in-class performance supports longer range; small package enables compact designs
MAX2842 Direct-conversion, zero-IF RF transceiver for 3.3GHz to 3.9GHz MIMO WiMAX
2x2 MIMO RF transceiver with best-in-class noise figure (3.8dB) and linearity specifications
Best-in-class performance supports longer range
MAX7032 300MHz to 450MHz ASK/FSK transceiver with low current drain
Under 7mA active receiver current; SPI programmable; programmable sleep/wake mode
Good in-building range with long battery life
MAX7031 300MHz to 450MHz FSK transceiver with low current drain
Under 7mA active receiver current; hardwired or microprocessor controllable; factory-preset frequencies
Good in-building range with long battery life
MAX7030 300MHz to 450MHz ASK transceiver with low current drain
Under 7mA active receiver current; hardwired or microprocessor controllable; factory-preset frequencies
Good in-building range with long battery life
RF transmitter
MAX7049* 288MHz to 945MHz ASK/FSK transmitter with low current drain
Up to 25mW Tx power; SPI programmable; less than 500nA shutdown current
Good in-building range (including 800MHz/900MHz) with long battery life
Powerline communications ICs
MAX2981/82* Broadband HomePlug 1.0 chipset Up to 14Mbps data transmission Robust, high-data-rate transmission with guaranteed latency for industrial environments
MAX2990/91 (G3-PLC Lite)
Narrowband OFDM PLC chipset Up to 100kbps data transmission or lower-data-rate robust mode for extremely noisy environments; DES/3DES encryption engine
Lower network implementation cost from ability to cross transformers
MAX2991/92* (G3-PLC)
Narrowband OFDM PLC chipset AES-128 encryption engine; adaptive tone mapping allows coexistence with FSK protocols; 6LoWPAN compression enables IPv6
Lower network implementation cost from ability to cross transformers
Multiprotocol transceivers
MAX3160E Programmable 2Tx/2Rx RS-232 or 1Tx/1Rx RS-485/RS-422
Supports RS-232, RS-422, and RS-485; handles up to 128 devices on the bus; 20-pin SSOP
Eases system configuration while saving space
MAX3161E Programmable 2Tx/2Rx RS-232 or 1Tx/1Rx RS-485/RS-422
Supports RS-232, RS-422, and RS-485; handles up to 256 devices on the bus; 24-pin SSOP
Eases system configuration while saving space
MAX3162E Dedicated 2Tx/2Rx RS-232 and 1Tx RS-485/RS-422
Supports RS-232, RS-422, and RS-485; handles up to 256 devices on the bus; 28-pin SSOP
Eases system configuration while saving space
UART
MAX3107 Single-channel SPI/I2C UART Integrated oscillator; 24Mbps data rate; PLL; shutdown modes
Reduces solution cost and size; offloads μC
(Continued on next page)
Recommended solutions
*Future product—contact the factory for availability.
40 MaximSmart Grid Solutions
CommunicationsRecommended solutions
Part Description Features Benefits
RS-485 transceivers
MAX13442E Fault-protected RS-485 transceiver ±80V fault protection; ±15kV ESD protection Eliminates external circuitry
MAX13485E RS-485 transceiver with enhanced ESD protection
±15kV ESD protection; fail-safe circuitry; hot-swappable
Saves space and provides robust protection
MAX3535E Isolated RS-485 transceiver with enhanced ESD protection
Robust ±2.5kV capacitive isolation Eliminates external optocoupler and power supply
MAX13412E/13E RS-485 transceivers optimized for isolated applications
AutoDirection circuitry; integrated LDO Minimize solution size
MAX13430E RS-485 transceiver for multivoltage systems Integrated low-voltage logic interface Interfaces directly to low-voltage FPGAs and ASICs, eliminating level translator
Transformer drivers
MAX253 1W primary-side transformer H-bridge driver for isolated supplies
Simple solution for producing an isolated power supply up to 1W
Simple open-loop circuit speeds PSU design, allowing faster time to market
MAX256 3W primary-side transformer H-bridge driver for isolated supplies
Simple solution for producing an isolated power supply up to 3W
Simple open-loop circuit speeds PSU design, allowing faster time to market
Power amplifier
MAX2235 1W autoramping power amplifier for 900MHz applications
+30dBm (1W) typical output power from a 3.6V supply or +28dBm from a 2.7V supply
Maximizes read range; operates directly from a single 2.7V to 5.5V supply, making it suitable for use with 3-cell NiCd or 1-cell Li+ batteries
DC-DC regulator
MAX15062* 36V, 300mA DC-DC regulator with integrated MOSFET
Low quiescent current; 2mm x 2mm TDFN package
High integration with small footprint saves up to 50% total board area compared to competing solutions
Analog-to-digital converters (ADCs)
MAX11103/05 12-bit, 3Msps/2Msps SAR ADCs 73dB SNR; SPI interface; high 1.7MHz full linear bandwidth; 1-channel (SOT23) and 2-channel (μMAX®, TDFN) options
Tiny SOT23, μMAX, and TDFN packages save space; serial interface simplifies data transmission
MAX1379/83 12-bit, 1.25Msps, 4-channel, simultaneous-sampling SAR ADCs
0 to 5V, 0 to 10V, or ±10V inputs; 70dB SNR; four single-ended or two differential inputs; SPI interface
Serial interface saves cost and space on digital isolators
Recommended solutions (continued)
For a list of Maxim's recommended smart grid communications solutions, please go to: www.maxim-ic.com/communications.
Energy measurementOverview
www.maxim-ic.com/smartgrid 41
Figure 1. The power profile of a laptop computer during power-up, steady-state, and power-down using two different plug-in power supplies.
Energy measurement
OverviewEnergydemandaroundtheworldispredictedtoincreaseataratethatwilllikelyoutstripourabilitytogenerateit.EstimatesbytheU.S.DepartmentofEnergyforecasttotalenergyconsumptionintheU.S.toincreaseby30%toover5,000billionkWhin2035,whilenewplannedgeneration(includingrenewablesources)isexpectedtogrowonly22%duringthisperiod.Increasedenergyefficiencyandimprovedenergymanagementarecriticaltoavertingthispotentialenergycrisis.
Traditionalopen-loopstrategiesformanagingpowerusagearecrudeandinefficient,resultinginlowerreliabilityandreduceddistributionstability.Engineersareworkingtoimprovepowerefficiencyinallelectronicapplications—commer-cialequipment,homeappliances,industrialmotors,andnetworkequipment.Increasingefficiency,however,isonlypartoftheequation.Betterenergymanagementand,consequently,comprehensivemeasurementsystemsareessential.Incorporatingfeedbackabouthowpowerisconsumedyieldsthebenefitsofaclosed-loopsystemandreduceswaste.Additionally,giving
energyusersgreatervisibilityintotheirpowerconsumptioncanhelpovercomeconsumerindifferencetoenergyconcerns.
Accuratemeasurementprovidesthefeedbacknecessarytounderstand,confirm,andmodifyourpowerconsumption.Itiscriticaltoimple-mentinganenergy-managementcontrolloopandprovidinginsightformaintenanceandfailurediagnostics.
Thischapteraddressestwokeyareasthatbenefitfromnewenergy-measurementtechnologies:residential/commercialpointofloads(POLs)anddatacenters.
Measuring point-of–load efficiencyIntelligentpower-managementschemesrequireaccurateenergymeasurement,notonlyatanaggregatelevel(e.g.,anentirebuilding)butalsoatthePOL(e.g.,airconditioner,lighting,dishwasher,orcomputer).
Smartmeterscantracktime-of-daypowerconsumptionandenableutilitiestoofferincentivestoconsumerstochangetheirusagepatterns.Toimproveautomation
weneedtoequipconsumerswithchoicesandenhancedservices.IndividualPOLsmustbetiedtoalocaldataandcontrolnetworkthatmonitorsandallowscontrolofthevariousloadswithinabuildingorhousehold.Servicescanbeenhancedthroughpower-qualitymeasurementsandusagestatistics,whichcanbeusedtoschedulemaintenance.Suchanetworkcanbeimplementedusingawidevarietyofconfigurationsandprotocols,dependingupontheapplication.
Alocaldataandcontrolnetworkthatincludesaccuratepowermeasure-mentcanenablesignificantcostsavingsbyidentifyinghowpowerisbeingused.Consumerswhocanseethatrunningtheairconditionercosts$200/month(valueofuse)orquantifythecostdifferencebetweenrunningthedryeratnooninsteadof7p.m.(time-valueofuse)aremorelikelytochangetheirusagepatterns.
Datathatusedtobeacquiredbyexpensivehigh-endutilitymetersisnowavailableforanorder-of-magni-tudelesscost.Powerfactor(PF),harmonicdistortion,activepower(watts),andapparentpower(VA)informationcanbereadilyavailableforoptimizingpower-delivery
50
45
40
WAT
TS (G
REEN
) AND
VA
(BLU
E)
POW
ER F
ACTO
R (R
ED L
INE)
SECONDS
35
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20
15
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5
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1.00
0.75
0.50
0.25
0
50
45
40
WAT
TS (G
REEN
) AND
VA
(BLU
E)
POW
ER F
ACTO
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ED L
INE)
SECONDS
35
30
25
20
15
10
5
0
1.00
0.75
0.50
0.25
0
Energy measurementOverview
42 MaximSmart Grid Solutions
budgets,forpredictingmaintenance,andforunderstandingthestrainonasystem.
Figure 1showsthepowerconsump-tionofalaptopcomputerusingtwodifferentplug-inpowersupplies.Eventhoughtheactualloadisthesame,thepowersuppliedfromthelinebytheutility,calledapparentpower,issubstantiallydifferentfromthepowerconsumedbytheload,calledactivepower.Suchdifferencesleadtounnecessaryandunaccountedforpowerloss.Withenergy-measurementsolutions,statisticscanbeusedtoadjustdeviceoperatingbehaviortooptimizeenergyefficiency.
Measurementaccuracyisimportanttoeffectivelyprotectagainstpowerfailuresandsafeguardequipment.Smalldropsinvoltageorlinefrequencycanindicatependingpowerfailure,enablingdevicestoswitchintoaprotectionmode.Additionally,voltagezero-crossinginformationcanbeusedtotimewhenrelaysshouldbeturnedonandofftoreducewearfromarcing.
Measuring data center efficiencyDatacentersaregettingalotofattention.TheEnvironmentalProtectionAgency(EPA)estimatesthatdatacentersaccountedfor1.5%ofU.S.electricityconsumptionin2006,andthisdemandisexpectedtonearlydoubleby2011,necessitatingthedevelopmentofanadditional10powerplants.Increasingdatacenterenergyefficiencycanhelpavoidtheseinfrastructuralcosts,whileofferingdatacenteroperatorssignifi-cantsavingsontheirelectricitybills.
ENERGYSTARrecentlyreleasedguidelinesfordatacenterstomitigatethisdemandthroughincreasedenergyefficiency.Keytotheseguidelinesisanewmetriccalledpowerusageeffectiveness(PUE),whichmeasuresfacilityinfra-
structureefficiency.PUEiscalculatedbydividingtotaldatacenterenergyconsumptionbytheITequipmentenergyconsumption.Thisrequiresmeteringatmultiplelocationswithinthedatacenter,includingtheunin-terruptiblepowersupply(UPS)andpowerdistributionunits(PDUs).
Real-timepowerconsumptiondataisneededtopreventcostlyoverloadingofbreakers,aswellasoverallocationtoequipmentinidleorstandbymodes.Armedwiththisinformation,datacentermanagerscanimplementoperationalstrategiesfordynamicpowercappingandreallocationtomaximizePUE.
Anaddedbenefitofenergy-measure-mentsystemsisthattheygivedatacentermanagersearlyfailurenotifica-tionsothatpreventativemaintenancecanbescheduled.Early-warningnotificationprovidestheextratimeneededtoseamlesslyutilizearedundantoptionbeforefailure.Energy-measurementsystemsenablecontinuousmonitoringofthehealthofthepowernetwork.Thiscapabilityisespeciallyimportantasequipmentissequenced,becauseitcanallowmechanismsthatavoidcircuitoverloadssuchasthosefoundduringablack-startrecovery.
Energy-measurement SoCsImplementationofintelligentpower-managementalgorithmsrequiresclearrepresentationofbothactualpowerconsumptionandactualdemand.Thisnecessitateshighaccuracyandmultiplemetrologyfunctions,including:distortion;active,reactive,andapparentpower;energy;RMSvoltageandcurrent;andfrequency.Thisinformationprovidesvaluablefeedbackforimprovingoperatingefficiency,preventingpowerfailure,andfacilitatingpower-upsequencingduringablackstart.
Measurementaccuracyisdeterminedbyresolution,precision,anddynamicrange.Manygeneral-purposeMCUs
arelimitedintheiraccuracyanddynamicrangebecauseoftheir10-or12-bitADCs.Discretedesigns,meanwhile,requiremultiplecompo-nents,in-depthknowledgeofACmetering,andextensivedevelop-menttime.
Today,SoCsareavailablethatbringthecapabilitiesofintelligentmeteringtoindividualdevices,fromPOLstoPDUs.Advancesinmanu-facturinganddesigntechnologyenablethemetrologycontainedinasingleSoCtomeetcriticalcost,functionality,robustness,andsizerequirements.Today'sstate-of-the-artSoCscannowbeintegratedintoservercabinets,UPSs,AC-DCpowermodules,PDUs,smartappliances,andluminaires.
Figure 2. A ZigBee®-based outlet-monitoring unit.
Figure 2showsaneasy-to-usedatacollectionsystemforPOLs.Thislow-costoutlet-monitoringunitdemonstratesthecapabilitiesofthe78M6612energy-measurementSoC.Itallowsuserstocollecttime-stampeddatafromapoweroutletandwirelesslytransferitforgraphicalanalysisorcomparisontoareferencemeter.
The78M6612AC-power-monitoringSoCcanmeasurefrom10mAto20Awithlessthan0.5%measure-menterroracrossawide-40°Cto+85°Ctemperaturerange.Itsonboard22-bitADCenablesthis
Energy measurementOverview
www.maxim-ic.com/smartgrid 43
widedynamicrangeandaccuracy,allowingthedevicetodetectvariousPOLlow-powermodes.Additionally,thewidedynamicrangeallowsthesamecircuitrytomonitoradiverserangeofapplications,providingeconomy-of-scalecostsavings.
Technical benefits of using an energy-measurement SoC• Accuratepowermeasurement
acrossawidecurrentdynamicrangecanbeusedtoconfirmdifferentlow-powermodes.For
example,asingleSoCcanmeasurefrom10mAto20Awith0.5%accuracy.
• Voltageandline-frequencymeasurementscanbeusedtodeterminetheappropriatetimetousepower,especiallywhenthesourceisnotthelocalutilitysupplier.Smalldropsinvoltageorlinefrequencyareanindicationofpendingpowerfailure.
• AC-voltagezerocrossingcanbeusedtosynchronizewhen
switchesshouldbeturnedofforon—anopportunitythatoccursevery8msto10ms,dependingonthelinefrequency.
• StatisticaldatacanbecollectedtodetectearlyfailureofalocalAC-DCpower-supplymoduleortoprovideinformationaboutthetypeofloadthatwasjustpluggedintotheoutlet.
44 MaximSmart Grid Solutions
Energy measurementFeatured products
A single chip implements a highly integrated outlet-monitoring system, saving the time, space, and cost of a multichip solution78M6612/78M6613
The78M6612/78M6613arehighlyintegrated,single-phaseACpower-measurementandmonitoring(AC-PMON)ICsforconsumerandenterpriseapplications.Whilethe78M6612targetsgeneral-purposeACpower-measurementapplications,the78M6613providesasimplifiedintegrationofsingle-phaseACpowermeasurementforthepower-supplymarket.Withaccuracyof0.5%Whorbetterovera2000:1currentrangeandovertemperature,eachsinglechipprovidesthemetrologydatatypicallyfoundincomplex,multichipmeteringsystems.
Featuringfouranaloginputs,bothdevicesuseTeridian’sSingleConverterTechnology®designandanintegrated32-bitcomputationengine(CE)tomeasureuptotwoACloadsorwalloutlets.Thedevicesarehighlyintegrated,whichreducesboardspaceandlowerscosts.Eachincludesan8-bitMPUcorewith32KBofembeddedflashmemory,aUARTinterface,andmultipleGPIOsforeasyintegrationintoanypowersupplyoroutlet-monitoringunit.The78M6612/78M6613consumeroughly30mWundertypicaloperatingconditions.The78M6612isavailablein64-pinLQFPand68-pinQFNlead-freepackages,whilethe78M6613isavailableina32-pinQFNlead-freepackage.
Designingwiththe78M6612/78M6613isgreatlysimplifiedwithacomplimentarysuiteofdevelopmenttools.Completeenergy-measurementfirmwaresupportstheserialUARTinterfaceandsimplifiescalibration,configuration,anddataextraction.FirmwareoptionsareavailableforemulatingI2C,PMBus™,orSMBusinterfacesusingtheonboardGPIOs.FirmwarecanbepreloadedduringICmanufactureormodifiedbycustomersasneeded.Softwarelibrariesgreatlyexpeditethedevelopmentprocess.
Benefits
• Single-chip solution provides the metrology accuracy typically found in multichip metering systems
– 0.5%Whaccuracyover2000:1currentrangeandovertemperature
• Adds intelligence to energy monitoring– Fullrangeofembeddedenergydiagnostics(powerfactor,harmonicdistortion,voltagesaganddip)foreachoutlet
– Predictspower-supplyfailures– Intelligentswitchrelaycontrol,includingzero-crossingdetectionforeachoutlet
• High integration reduces the bill-of-materials (BOM) cost
– Monitorstwooutletssimultaneously– Dual-outletpowerreducescostperoutlet– Completeenergy-measurementcommunicationprotocol
– Eliminatestheneedforexternalcomponentstobootorloadcalibrationparameters
• Reduces time to market– Softwaresupporttoolssimplifydesigncycles
– Nocodedevelopmentisrequiredbythecustomer
– Completeenergy-measurementandhost-interfacefirmwareavailable
Diagram of a typical energy-measurement SoC embedded in a single-phase application.
2000:1 22-BIT ∆-∑ ADC
MUL
TIPL
EXER 32-BIT
REAL-TIMECOMPUTATIONENGINE (CE)
8051 MCUSINGLE CLOCK/INSTRUCTION
5MHz
2KB SRAM
32KB FLASHTEMP COMPENSATION
UART
GPIOsTEMPERATURE AND
ALARMS STATUS
VOLTAGE, CURRENT, ANDLINE FREQUENCY
ACTIVE, REACTIVE, ANDAPPARENT POWER
POWER FACTOR ANDPHASE ANGLE
SINGLE CONVERTERTECHNOLOGY ARCHITECTURE
SINGLE-PHASE AC
CALIBRATIONCOMMANDS
CONFIGURATIONAND RELAY CONTROL
78M6612
SHUNTOR CTAC LOAD
INTERFACE-SPECIFIC CODE
8051 AC-PMON POST PROCESSING
32-BIT CE
www.maxim-ic.com/smartgrid 45
Energy measurementFeatured products
Benefits
• Single-chip solution provides the metrology accuracy typically found in multichip metering systems
– 0.5%Whaccuracyover2000:1currentrangeandovertemperature
• Adds intelligence to energy monitoring– Measuresthepowerfactorforeachoutlet– Predictspower-supplyfailures– Intelligentswitchrelaycontrol,includingzero-crossingdetectionforeachoutlet
• High integration reduces BOM cost– Monitorseightoutletssimultaneously– Octal-outletpowerreducescostperoutlet– Completeenergy-measurementcommunicationprotocolinasinglechip
• Shortens time to market– Softwaresupporttoolssimplifydesigncycles
– Nocodedevelopmentisrequiredbythecustomer
– Completeenergy-measurementandhost-interfacefirmwareavailable
78M6618
The78M6618isahighlyintegrated,single-phase,8-outlet,power-measurementandmonitoringSoC.ItisdesignedformultichannelpowermonitoringinPDUs,smartbreakersandrelaypanelsforhomes,andbuildingautomation.
The78M6618’saccuracyis0.5%Whovera2000:1currentrangeandovertemperature—whatonewouldtypicallyfindinmultichipmeteringsystems.Ithasunprecedentedintegrationinanenergy-measurementIC:a32-bitCE,anMPUcore,128KBflashmemory,4KBsharedRAM,andanRTC;threelow-powermodeswithinternaltimerorexternaleventwake-up;twoUARTs;andanI2C/MICROWIRE®EEPROMinterfaceoranSPI™interface.TheSoCalsofeaturesTeridian’sSingleConverterTechnologydesign,whichincorporatesa22-bitdelta-sigmaADC,10analoginputs,digitaltemperaturecompensation,andaprecisionvoltagereference.Withthesemanycapabilities,the78M6618supportsawiderangeofsingle-phasemeteringapplications.Needingveryfewexternalcomponents,thissinglechipalsogreatlyreducesthecostofimplementingcomplexPDUsystems.
Acompletearrayofin-circuitemulationanddevelopmenttoolsassistscustomersandreducesdesigntime.Metrologylibrariesarespecificallydesignedformeasurementandswitchcontrolofeightsingle-phaseACoutlets(samephase).Asoftwaredevelopmentkit,referencedesigns,andreferencemanualsexpeditedevelopmentandcertificationofpowerandenergymeasurement.
8-channel energy-measurement IC simplifies complex server PDU system design while reducing costs
(Block diagram on next page)
46 MaximSmart Grid Solutions
Energy measurementFeatured products
8-channel energy-measurement IC simplifies complex server PDU system design while reducing costs (continued)
AC-DCPOWER SUPPLY
I1
I2
I3
I4
I5
I6
I7
I8
I1
OUTLET1CT1
CT2
CT3
CT4
CT5
CT6
CT7
CT8
OUTLET2
OUTLET3
OUTLET4
OUTLET5
OUTLET6
OUTLET7
OUTLET8
LIVE
LIVE
NEUTRALNEUTRAL
I2I3I4I5I6I7I8V
V
V1
AUX
V3.3A V3.3D GNDA GNDD
VBATT
V2.5TX1RX1
TX2RX2
XIN
XOUT
VREF
COMPARATOR
A/D CONVERTER
REGULATOR
UARTs
I2C
SPI
TIMERS
RTC
OSC/PLL
TEMPSENSOR
RAM
COMPUTATIONENGINE
FLASH
80515MPU
ICEDIGITAL I/O
DCPOWER FAULT
RELAY DRIVERS,7-SEG LCD, ETC.
32kHz
BATTERY(OPTIONAL)
CONSOLE
EEPROM(OPTIONAL)
HOST μC,ADDITIONAL 78M6618s
78M6618
Block diagram of the 78M6618 power- and energy-measurement IC.
Legal noticesTrademark information
www.maxim-ic.com/smartgrid 47
Trademark information
µMAXisaregisteredtrademarkofMaximIntegratedProducts,Inc.
1-WireisaregisteredtrademarkofMaximIntegratedProducts,Inc.
AutoShutdownisatrademarkofMaximIntegratedProducts,Inc.
CENELECisaservicemarkoftheEuropeanCommitteeforElectrotechnicalStandardization.
EchelonisaregisteredtrademarkofEchelonCorporation.
HomePlugisaregisteredservicemarkofHomePlugPowerlineAlliance,Inc.
IEEEisaregisteredservicemarkoftheInstituteofElectricalandElectronicsEngineers,Inc.
InnovationDeliveredisaregisteredtrademarkandregisteredservicemarkofMaximIntegratedProducts,Inc.
MaximisaregisteredtrademarkofMaximIntegratedProducts,Inc.
MAXQisaregisteredtrademarkofMaximIntegratedProducts,Inc.
MICROWIREisaregisteredtrademarkofNationalSemiconductorCorporation.
PMBusisatrademarkofSMIF,Inc.
SingleConverterTechnology,formerlyatrademarkofTeridianSemiconductor,isaregisteredtrademarkofMaximIntegratedProducts,Inc.
SPIisatrademarkofMotorola,Inc.
Wi-FiisaregisteredcertificationmarkofWi-FiAllianceCorporation.
WiMAXisaregisteredcertificationmarkoftheWiMAXForum.
ZigBeeisaregisteredtrademarkandregisteredservicemarkoftheZigBeeAlliance.
Z-WaveisaregisteredtrademarkofSigmaDesigns,Inc.
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48 MaximSmart Grid Solutions
Maxim Integrated Products, Inc. • 120 San Gabriel Drive Sunnyvale, California 94086 • 1-408-737-7600
www.maxim-ic.com/smartgrid