maximumykt

TheDesignofLowPowerBandgapReferenceYunqianZhang1,a,WeidongGeng1,b*,XiZeng1,c,ZhixunYang2,a1InstituteofPhoto-electronicsThinFilmDevicesandTechniqueofNankaiUniversity,KeyLaboratoryofPhoto-ElectronicsThinFilmDevicesandTechniqueofTianjin,KeyLaboratoryofOpto-electronicInformationScienceandTechnology,NankaiUniversity,Tianjin300071,China;2BeijingSigmaMicroCompany,Beijing100085,China.
1,azhangyq_nku@163.
com,1,bgengwd@nankai.
edu.
cn,1,czengxi1213@126.
com2,ayangzx@sigma.
com*Correspondingauthor:WeidongGeng:gengwd@nankai.
edu.
cn.
Keywords:Bandgap,Lowpower,Non-overlapclock,Capacitance-RatioAbstract.
Thispaperpresentsanovellowpowerbandgapreferencecircuit,thebandgapreferenceadoptshalfaperiodworkingmechanism.
Theoperationalamplifierdoesn'tworkduringtheswitchedcapacitornetworksampling.
Andtheoperationalamplifierworksafterthechargebalanced.
Thebandgapreferencerunsdiscontinuously.
Thedesignimplementsinstandard0.
18umCMOSprocess.
Thesimulationresultshowsthat,thecircuitconsumes19.
8uAat3.
3V.
Thenoiseofthecircuitinlowfrequencyachieves3.
9/√andthetemperaturecoefficientis21ppm/℃.
1.
IntroductionReferencevoltageblockisthefundamentalpartofthepowermoduleofelectricalsystem,itsperformanceparameters,suchasaccuracystabilityandsoon,decidestheperformanceoftheelectricalsystem.
Inrecentyears,especially,electronicproductsbecomeminiaturizationandportability,referencevoltageblockneedslowerpowerdissipation.
Thedesignofthereferencevoltageblockadoptsbandgapreferencestructuregenerally.
In2012,Zhouzekunpresentsahighprecisionhigh-ordercurvature-compensatedbandgapreferencecompatiblewithstandardBiCMOSprocess.
Experimentalresultsoftheproposedbandgapreferencedemonstratethatatemperaturecoefficientof5ppm/℃isrealizedat3.
6Vpowersupplywhiledissipatingamaximumsupplycurrentof25uA[1].
Inthesameyear,Peng-YuChenpresentsabandgapreferencewhichusesalow-gainamplifiertogenerateanaccuratereferencevoltage.
Theaveragepowerconsumptionisapproximately24.
6uWat1Vsupplyvoltage,whichexport434.
2mV[2].
In2013,CaoYingshowsatotal-ionizing-doseradiationtoleranceofbandgapreferenceindeep-submicronCMOStechnology,whichreachesatemperaturecoefficientof15ppm/℃from-40℃to125℃andconsumes50uA[3].
Inthesameyear,A.
Martnez-Nietodesignsalowtemperaturecoefficient,curvature-compensatedCMOSbandgapvoltagereference,whichimplementsinstandard0.
18umCMOSprocesswith1.
8Vpowersupply.
Thecircuithasa4-bittrimmingcircuittocompensateforprocessvariations.
Theoutputvoltageis1.
225VandshowsaTClowerthan2ppm/℃overatemperaturerangeof160℃andthepowerdissipationis620uW[4].
In2014,TommasoVerginepresetsabandgapreferencecircuitwhichhasbeendesignedtobeRadiation-Hardupto1Grad.
Thecircuithasbeendevelopedinacommercial65nmCMOStechnologywith1.
2Vofnominalvoltagesupply.
Thepowerconsumptionis240uWandtheoutputvoltageis331.
6mV[5].
Inthesameyear,BillMaproposesanovelCMOSbandgapreferencewithhigh-ordercurvature-compensationbyusingMOStransistorsoperatinginweakinversionregion.
Theexperimentalresultsshowthatthebandgapreferenceachieves4.
5ppm/℃andconsumes36uAat1.
2V[6].
Allresearchmentionedaboveemploytypicalbandgapreferencestructurewiththemechanismofworkingcontinuously.
Theprincipleofthetypicalbandgapreferencestructureamplifiesthevoltagewithratio-resistance,whichintroducesthethermalnoiseunavoidably.
Inallusiontoproblemsproposed,thispaperpresentsamechanismofhalfaperiodwhichreducestheworkingtimeoftheoperationalamplifiertolessenthepowerdissipation.
Thisbandgapreferencecircuitadoptscapacitancetoamplifythevoltagewithlowerthermalnoise.
2.
Ratio-capacitanceBandgapReferenceCircuitBasedonprincipleofswitchedcapacitance,capacitanceratiobandgapreferencedividedtheworkingtimeintotwonon-overlappartsemployingtwonon-overlapclock,asshowedinFig.
1.
ThecapacitanceC1samplesVBE1-VBE2inthefirstphaseandtheoutputvoltageofthecircuitismaintainedbyloadcapacitance.
Accordingtotheprincipleofchargeconservation,thechargeofcapacitanceC1transferstocapacitanceC2.
ThemultipleofC1toC2willamplifythevalueofVBE1-VBE2whiletheswitchattheoutputendclosingwiththeoutputvoltageVbg.
Fig.
1CapacitanceRatioBandgapReference3.
HalfaperiodWorkingmechanismCapacitanceratiobandgapreferencedividestheworkingtimeintotwoparts.
Theoperationalamplifierisusedasabufferinthefirstphasewhilesamplingthedifferenceofvoltage.
Accordingtotheprincipleofchargeconservation,thecircuitmultiplythedifferenceofvoltage.
Thestableoutputreferencevoltageiscomposedofthenegativetemperaturecoefficientofthevoltageandthemagnifiedpositivetemperaturecoefficientofthevoltage.
Powerdissipationoftheoperationalamplifieristhemainsourceinthebandgapreference.
Auniversalmethodoflow-powerdesignistoreducethepowerconsumption.
Reducingtheworkingtimeisalsoaneffectivewaytodesignalowpowerbandgapreference.
Theoperationalamplifierinthecapacitanceratiobandgapreferencedoesn'tneedtoworkinthefirstphasewithoutlossofchargeinthesamplingcapacitor.
Andtheoperationalamplifierinthebandgapreferenceworksinclosedloop,exportingthestableoutputvoltageasreferencevoltagedirectlyinthesecondphase.
Thispapersavesthepowerdissipationoftheoperationalamplifierinthefirstphasewithclosedoperationalamplifier.
Bottomplatesamplingtechnique,replacingtheclosedoperationalamplifierusedasabuffer,hasbeenusedinthedesignforsavingthechargeatthenegativeport.
Afteroptimizingthestructure,showedinFig.
1forlowerpowerdissipation,enablesignalEN_Phase2hasbeenaddedtotheoperationalamplifier,asFig.
2.
ThechargeinthecapacitanceC1transferstothecapacitanceC2inthesecondphasewiththeopeningoperationalamplifier.
Forthetimebeing,theoutputendofoperationalamplifierlinkstotheoutputendofthecircuitwhentheoutputvoltageoftheoperationalamplifierbecomesthereferencevoltageVbg.
Vbg=VBE1+nVBE.
(1)Fig.
2Half-periodCapacitorRatioBandgapReferencePhase1Phase2Phase2Phase2C1C2CLVBE1VBE2VbgPhase1Phase1Phase2Phase2Phase2C1C2CLVBE1VBE2VbgEN_Phase2Theoperationalamplifierinthebandgapreferenceadoptsthemechanismofhalfcycleworktimewhichcanreducethepowerconsumptionavailably.
Afterturningontheoperationalamplifier,thecircuitchargetheparasiticcapacitance,whichdecreasesthesettlingtimeoftheoutputvoltagewiththehalfaperiodworkingmechanism.
Sothehalfaperiodworkingmechanismneedsfasteroperationalamplifierwhichwillincreasethepowerconsumptionofthecircuit.
Apeakvalueoftheoutputvoltagewillbeproducedbecauseofnon-overlapclock,whichinfluencestheaccuracyofthebandgapreference.
AsshownasFig.
3,theenablesignalEN_Phase2hasbeenoptimizedtoresolvetheproblemoftheparasiticcapacitance.
Ensuringtheparasiticcapacitancecharged,theenablesignalEN_Phase2Fwillbeenabledadvanced.
Fig.
3OptimizedHalf-periodCapacitorRatioBandgapReference4.
SimulationExperimentsandAnalysisConsideringthecurrentapplyingtotheloadoutsideandtheloadcapacitanceinside,thespeedoftheclockshouldbechosen.
Theparasiticcapacitancesshouldreachthebalancedstatebeforetheoperationalamplifierworkingintheclosedloop.
Aheadofthesecondphase,theoperationalamplifierhasbeenenabledtoensurestableoutputvoltagewhilethecapacitanceratiomultipliesthevoltage.
Inlogic,thefallingedgeoftheEN_Phase2FissynchronizedwiththerisingedgeofthePhase2but,actually,thefallingedgeoftheEN_Phase2Fenablestheoperationalamplifierinadvance.
ThetimeinadvanceofEN_Phase2Fcanbedecidedconsideringthevalueoftheparasiticcapacitance.
Inthispaper,theratioofcapacitancebetweenC1andC2iselectedas4,aftertakingareaofthechip,powerconsumedbygeneratingtheVBE1andVBE2andthenoisecharacterofthecapacitance.
Thetemperaturecharacteristicofthecapacitanceratiobandgapreferencefrom-20℃to80℃hasbeenshownasFig.
4withthevarietyof7mVattheendofthecircuit.
Theoutputvoltagecanbestableat10.
75uswithsteadypowersupply,asshowninFig.
5.
Fig.
4SimulationResultofTemperaturecharacteristicFig.
5SimulationResultoftransientresponseTable1showsthesimulationresult.
Aftercomparingthisworkwithothers,thepowerdissipationofthecircuitissuperiortoothers.
Table1AnalysisofSimulationResultPerformanceParameterThiswork[2][3]SupplyCurrent(uA)19.
8uA24.
6uA50uATemperatureCoefficient(ppm/℃)21ppm/℃13.
29ppm/℃15ppm/℃Phase1Phase2Phase2Phase2C1C2CLVBE1VBE2VbgEN_Phase2F5.
SummaryAfteranalyzinganddiscussingtheapplicationanddevelopmentdirectionofbandgapreference,thispaperpresentsalowpowerratio-capacitancebandgapreferencecircuit,whichcanreducepowerdissipation.
ThecircuitadoptscascadeOp-ampwhichcanimproveresponsespeedandaccuracyofthecircuit.
Simulationresultshowsthatthetotalpowerdissipationis19.
8uAat3.
3V,low-frequencynoiseachieves3.
9uV/√Hzandthetemperaturecoefficientofthecircuitis21ppm/℃.
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