Linewww.7160.com

UC1625-SPwww.
ti.
comSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011RAD-TOLERANTCLASSV,BRUSHLESSDCMOTORCONTROLLERCheckforSamples:UC1625-SP1FEATURESHigh-speedCurrent-SenseAmplifierwithIdealDiodeQML-VQualified,SMD5962-91689Pulse-by-PulseandAverageCurrentSensingRad-Tolerant:40kRad(Si)TID(1)Over-VoltageandUnder-VoltageProtectionDrivesPowerMOSFETsorPowerDarlingtonsDirectionLatchforSafeDirectionReversalDirectlyTachometer50-VOpenCollectorHigh-SideDriversTrimmedReferenceSources30mALatchedSoftStartProgrammableCross-ConductionProtection(1)Radiationtoleranceisatypicalvaluebaseduponinitialdevicequalificationwithdoserate=10mrad/sec.
RadiationLotTwo-QuadrantandFour-QuadrantOperationAcceptanceTestingisavailable-contactfactoryfordetials.
DESCRIPTION/ORDERINGINFORMATIONTheUC1625motorcontrollerintegratesmostofthefunctionsrequiredforhigh-performancebrushlessdcmotorcontrolintoonepackage.
WhencoupledwithexternalpowerMOSFETsorDarlingtons,thisdeviceperformsfixed-frequencyPWMmotorcontrolineithervoltageorcurrentmodewhileimplementingclosedloopspeedcontrolandbrakingwithsmartnoiserejection,safedirectionreversal,andcross-conductionprotection.
Althoughspecifiedforoperationfrompowersuppliesbetween10Vand18V,theUC1625cancontrolhighervoltagepowerdeviceswithexternallevel-shiftingcomponents.
TheUC1625containsfast,high-currentpush-pulldriversforlow-sidepowerdevicesand50-Vopen-collectoroutputsforhigh-sidepowerdevicesorlevelshiftingcircuitry.
TheUC1625ischaracterizedforoperationoverthemilitarytemperaturerangeof–55°Cto125°C.
ORDERINGINFORMATION(1)ORDERABLEPARTTAPACKAGE(2)TOP-SIDEMARKINGNUMBER5962-9168902VYA–55°Cto125°CCDIP–JT5962-9168902VYAUC1625-SP(1)Forthemostcurrentpackageandorderinginformation,seethePackageOptionAddendumattheendofthisdocument,orseetheTIwebsiteatwww.
ti.
com.
(2)Packagedrawings,thermaldata,andsymbolizationareavailableatwww.
ti.
com/packaging.
1Pleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsofTexasInstrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet.
PRODUCTIONDATAinformationiscurrentasofpublicationdate.
Copyright2011,TexasInstrumentsIncorporatedProductsconformtospecificationsperthetermsoftheTexasInstrumentsstandardwarranty.
Productionprocessingdoesnotnecessarilyincludetestingofallparameters.
UC1625-SPSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011www.
ti.
comTypicalApplicationABSOLUTEMAXIMUMRATINGS(1)(2)overoperatingfree-airtemperaturerange(unlessotherwisenoted)VALUEUNITVCC20SupplyvoltagePWRVCC20PWMIN–0.
3to6E/AIN(+),E/AIN(–)–0.
3to12VISENSE1,ISENSE2–1.
3to6OV-COAST,DIR,SPEED-IN,SSTART,QUADSEL–0.
3to8H1,H2,H3–0.
3to12PUOutputVoltage–0.
3to50PU+200continuousPD±200continuousE/A±10OutputcurrentmAISENSE–10TACHOUT±10VREF–50continuousTJMaximumJunctionTemperature150°C(1)Currentsarepositiveintoandnegativeoutofthespecifiedterminal.
(2)Stressesabovetheseratingsmaycausepermanentdamage.
Exposuretoabsolutemaximumconditionsforextendedperiodsmaydegradedevicereliability.
Thesearestressratingsonlyandfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthosespecifiedisnotimplied.
2SubmitDocumentationFeedbackCopyright2011,TexasInstrumentsIncorporatedProductFolderLink(s):UC1625-SPUC1625-SPwww.
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comSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011RECOMMENDEDOPERATINGCONDITIONSoveroperatingtemperaturerange(unlessotherwisenoted)MINNOMMAXUNITVCCSupplyVoltage1018VPUOutputCurrent+85mAcontinuousPD±85mAcontinuousTAOperatingtemperaturerange-55125°CTable1.
THERMALRATINGSTABLERθJA(°C/W)RθJC(°C/W)PACKAGE(Junction-to-ambientthermalresistance)(Junction-to-casethermalresistance)DIL-28(JT)43.
14.
95Figure1.
CONNECTIONDIAGRAMCopyright2011,TexasInstrumentsIncorporatedSubmitDocumentationFeedback3ProductFolderLink(s):UC1625-SPUC1625-SPSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011www.
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comELECTRICALCHARACTERISTICSUnlessotherwisestated,thesespecificationsapplyoverthefulltemperaturerange,typicalvaluesatTA=25°C;PwrVCC=VCC=12V;ROSC=20ktoVREF;COSC=2nF;RTACH=33k;CTACH=10nF;andalloutputsunloaded.
TA=TJ.
PARAMETERTESTCONDITIONSMINTYPMAXUNITOverallSupplycurrent14.
530.
0mAVCCturn-onthreshold-55°Cto125°C8.
658.
959.
55VVCCturn-offthreshold7.
758.
058.
55Overvoltage/CoastOV-COASTinhibitthreshold1.
651.
751.
85OV-COASTrestartthreshold1.
5351.
651.
75V-55°Cto125°COV-COASThysteresis0.
050.
100.
155OV-COASTinputcurrent–10–110μALogicInputsH1,H2,H3lowthreshold0.
81.
01.
25-55°Cto125°CVH1,H2,H3highthreshold1.
61.
92.
0H1,H2,H3inputcurrent-55°Cto125°C,to0V–400–250–120μAQUADSEL,dirthresholds0.
81.
43.
0VQUADSELhysteresis70130mVDIRhysteresis-55°Cto125°C0.
40.
60.
9VQUADSELinputcurrent–3050150μADIRinputcurrent–30–130PWMAmp/ComparatorE/AIN(+),E/AIN(–)inputcurrentTo2.
5V–5.
0–0.
15.
0μAPWMINinputcurrentTo2.
5V0330Errorampinputoffset0V253.
50V-55°C0.
254.
2PullupcurrentTo0V,25°C-16–10–5μATo0V,-55°Cto125°C–17.
5-5SSTARTDischargecurrentTo2.
5V0.
10.
43.
0mARestartthreshold0.
10.
20.
3VCurrentAmpGainISENSE1=0.
3V,ISENSE2=0.
5Vto0.
7V1.
751.
952.
15V/VLevelshiftISENSE1=0.
3V,ISENSE2=0.
3V2.
42.
52.
65Peakcurrentthreshold0.
140.
200.
26VISENSE1=0V,forceISENSE2Overcurrentthreshold0.
260.
300.
36ISENSE1,ISENSE2inputcurrent–850–3200To0VμAISENSE1,ISENSE2offsetcurrent-12±212RangeISENSE1,ISENSE2–12VTachometer/BrakeTACH-OUThighlevel4.
755.
3-55°Cto125°C,10kto2.
5VVTACH-OUTlowlevel0.
2Ontime170220280μsOntimechangewithtemp-55°Cto125°C0.
1%RC-BRAKEinputcurrentTo0V–4.
0–1.
9mA4SubmitDocumentationFeedbackCopyright2011,TexasInstrumentsIncorporatedProductFolderLink(s):UC1625-SPUC1625-SPwww.
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comSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011ELECTRICALCHARACTERISTICS(continued)Unlessotherwisestated,thesespecificationsapplyoverthefulltemperaturerange,typicalvaluesatTA=25°C;PwrVCC=VCC=12V;ROSC=20ktoVREF;COSC=2nF;RTACH=33k;CTACH=10nF;andalloutputsunloaded.
TA=TJ.
PARAMETERTESTCONDITIONSMINTYPMAXUNITThresholdtobrake,RC-brake0.
81.
01.
2VBrakehysteresis,RC-brake0.
090.
4-55°Cto125°CSPEED-INthreshold220257290mVSPEED-INinputcurrent–30–530μALow-SideDrivers(1)Voh,–1mA,downfromVCC1.
602.
50Voh,–50mA,downfromVCC1.
752.
45-55°Cto125°CVVol,1mA0.
050.
4Vol,50mA0.
360.
9Rise/falltime10%to90%slewtime,into1nF50500nsHigh-SideDriversVol,1mA0.
10.
4-55°Cto125°CVVol,50mA1.
01.
8LeakagecurrentOutputvoltage=50V30μAFalltime10%to90%slewtime,50mAload50nsOscillatorFrequency-55°Cto125°C3080kHzReferenceIref=0mA,25°C4.
855.
05.
15OutputvoltageV-55°Cto125°C4.
75.
05.
3Loadregulation0mAto–20mAload–40–5mVLineregulation10Vto18VVCC–10–110Shortcircuitcurrent-55°Cto125°C20100150mAMiscellaneousOutputturn-ondelay1μsOutputturn-offdelay1(1)Currentavailablefromthesepinscanpeakashighas0.
5A.
Copyright2011,TexasInstrumentsIncorporatedSubmitDocumentationFeedback5ProductFolderLink(s):UC1625-SPUC1625-SPSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011www.
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comBlockDiagram6SubmitDocumentationFeedbackCopyright2011,TexasInstrumentsIncorporatedProductFolderLink(s):UC1625-SPUC1625-SPwww.
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comSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011DEVICEINFORMATIONTerminalFunctionsTERMINALDESCRIPTIONNAMENO.
ThepositiondecoderlogictranslatestheHallsignalsandtheDIRsignaltothecorrectdriversignals(PUsandPDs).
Topreventoutputstagedamage,thesignalonDIRisfirstloadedintoadirectionlatch,thenshiftedthroughatwo-bitregister.
AslongasSPEED-INislessthan250mV,thedirectionlatchistransparent.
WhenSPEED-INishigherthan250mV,thedirectionlatchinhibitsallchangesindirection.
SPEED-INcanbeconnectedtoTACH-OUTthroughafilter,sothatthedirectionlatchisonlytransparentwhenthemotorisspinningslowly,andhastoolittlestoredenergytodamagepowerdevices.
Additionalcircuitrydetectswhentheinputandoutputofthedirectionlatcharedifferent,orDIR,SPEED-IN6,7whentheinputandoutputoftheshiftregisteraredifferent,andinhibitsalloutputdrivesduringthattime.
Thiscanbeusedtoallowthemotortocoasttoasafespeedbeforereversing.
Theshiftregisterensuresthatdirectioncannotbechangedinstantaneously.
TheregisterisclockedbythePWMoscillator,sothedelaybetweendirectionchangesisalwaysgoingtobebetweenoneandtwooscillatorperiods.
At40kHz,thiscorrespondstoadelayofbetween25μsand50μs.
Regardlessofoutputstage,25μsdeadtimeshouldbeadequatetoensurenooverlapcross-conduction.
TogglingDIRcausesanoutputpulseonTACH-OUTregardlessofmotorspeed.
E/AIN(+)andE/AIN(–)arenotinternallycommittedtoallowforawidevarietyofuses.
TheycanbeconnectedtotheISENSE,toTACH-OUTthroughafilter,toanexternalcommandvoltage,toaD/Aconverterforcomputercontrol,ortoanotheropampformoreelegantfeedbackloops.
Theerroramplifieriscompensatedforunitygainstability,soE/AOUTcanbetiedtoE/AIN(–)forfeedbackandmajorloopcompensation.
E/AIN(+),E/AIN(–),E/A1,28,27,26E/AOUTandPWMIndrivethePWMcomparator.
Forvoltage-modePWMsystems,PWMInOUT,PWMINcanbeconnectedtoRC-OSC.
ThePWMcomparatorclearsthePWMlatch,commandingtheoutputstochop.
TheerroramplifiercanbebiasedoffbyconnectingE/AIN(–)toahighervoltagethan/EAIN(+).
Whenbiasedoff,E/AOUTappearstotheapplicationasaresistortoground.
E/AOUTcanthenbedrivenbyanexternalamplifier.
GND15AllthresholdsandoutputsarereferredtotheGNDpinexceptforthePDandPUoutputs.
Thethreeshaftpositionsensorinputsconsistofhysteresiscomparatorswithinputpullupresistors.
LogicthresholdsmeetTTLspecificationsandcanbedrivenby5-VCMOS,12-VCMOS,NMOS,oropen-collectors.
Connecttheseinputstomotorshaftpositionsensorsthatarepositioned120electricaldegreesapart.
Ifnoisysignalsareexpected,zenerclampandfiltertheseinputswith6-VH1,H2,H38,9,10zenersandanRCfilter.
Suggestedfilteringcomponentsare1kand2nF.
Edgeskewinthefilterisnotaproblem,becausesensorsnormallygeneratemodifiedgraycodewithonlyoneoutputchangingatatime,butriseandfalltimesmustbeshorterthan20μsforcorrecttachometeroperation.
Motorswith60electricaldegreepositionsensorcodingcanbeusedifoneortwoofthepositionsensorsignalsisinverted.
Thecurrentsenseamplifierhasafixedgainofapproximatelytwo.
Italsohasabuilt-inlevelshiftofapproximately2.
5V.
ThesignalappearingonISENSEis:ISENSE=2.
5V+(2*ABS(ISENSE1–ISENSE2))ISENSE1andISENSE2areinterchangeableandcanbeusedasdifferentialinputs.
Thedifferentialsignalappliedcanbeashighas±0.
5Vbeforesaturation.
IfspikesareexpectedonISENSE1orISENSE2,theyarebestfilteredbyacapacitorfromISENSEtoground.
FilteringthiswayallowsfastsignalinversionstobecorrectlyprocessedISENSE1,ISENSE2,bytheabsolutevaluecircuit.
Thepeak-currentcomparatorallowsthePWMtoentera3,4,5ISENSEcurrent-limitmodewithcurrentinthewindingsneverexceedingapproximately0.
2V/RSENSE.
Theovercurrentcomparatorprovidesafail-safeshutdownintheunlikelycaseofcurrentexceeding0.
3V/RSENSE.
Then,softstartiscommanded,andalloutputsareturnedoffuntilthehighcurrentconditionisremoved.
ItisoftenessentialtousesomefilterdrivingISENSE1andISENSE2torejectextremespikesandtocontrolslewrate.
Reasonablestartingvaluesforfiltercomponentsmightbe250-seriesresistorsanda5-nFcapacitorbetweenISENSE1andISENSE2.
Inputresistorsshouldbekeptsmallandmatchedtomaintaingainaccuracy.
Thisinputcanbeusedasanover-voltageshut-downinput,asacoastinput,orboth.
ThisOV-COAST23inputcanbedrivenbyTTL,5-VCMOS,or12-VCMOS.
Copyright2011,TexasInstrumentsIncorporatedSubmitDocumentationFeedback7ProductFolderLink(s):UC1625-SPUC1625-SPSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011www.
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comTerminalFunctions(continued)TERMINALDESCRIPTIONNAMENO.
TheseoutputscandrivethegatesofN-channelpowerMOSFETsdirectlyortheycandrivethebasesofpowerDarlingtonsifsomeformofcurrentlimitingisused.
Theyaremeanttodrivelow-sidepowerdevicesinhigh-currentoutputstages.
CurrentavailablefromthesepinsPDA,PDB,PDC12,13,14canpeakashighas0.
5A.
Theseoutputsfeatureatruetotem-poleoutputstage.
Bewareofexceedingdevicepowerdissipationlimitswhenusingtheseoutputsforhighcontinuouscurrents.
Theseoutputspullhightoturna"low-side"deviceon(activehigh).
Theseoutputsareopen-collector,high-voltagedriversthataremeanttodrivehigh-sidepowerdevicesinhigh-currentoutputstages.
Theseareactivelowoutputs,meaningthattheseoutputspulllowtocommandahigh-sidedeviceon.
TheseoutputscandrivePUA,PUB,PUC16,17,18low-voltagePNPDarlingtonsandP-channelMOSFETsdirectly,andcandriveanyhigh-voltagedeviceusingexternalchargepumptechniques,transformersignalcoupling,cascodelevel-shifttransistors,oropto-isolateddrive(high-speedoptodevicesarerecommended).
(Seeapplications).
ThissupplypincarriesthecurrentsourcedbythePDoutputs.
WhenconnectingPDoutputsdirectlytothebasesofpowerDarlingtons,thePWRVCCpincanbecurrentlimitedwithaPWRVCC11resistor.
Darlingtonoutputscanalsobe"BakerClamped"withdiodesfromcollectorsbacktoPWRVCC.
(SeeApplications)Thedevicecanchoppowerdevicesineitheroftwomodes,referredtoas"two-quadrant"(QuadSellow)and"fourquadrant"(QuadSelhigh).
Whentwo-quadrantchopping,thepulldownpowerdevicesarechoppedbytheoutputofthePWMlatchwhilethepullupdriversremainon.
Theloadchopsintoonecommutationdiode,andexceptforback-EMF,willexhibitslowdischargecurrentandfasterchargecurrent.
Two-quadrantchoppingcanbeQUADSEL22moreefficientthanfour-quadrant.
Whenfour-quadrantchopping,allpowerdriversarechoppedbythePWMlatch,causingtheloadcurrenttoflowintotwodiodesduringchopping.
Thismodeexhibitsbettercontrolofloadcurrentwhencurrentislow,andispreferredinservosystemsforequalcontroloveraccelerationanddeceleration.
TheQUADSELinputhasnoeffectonoperationduringbraking.
EachtimetheTACH-OUTpulses,thecapacitortiedtoRC-BRAKEdischargesfromapproximately3.
33Vdownto1.
67Vthrougharesistor.
ThetachometerpulsewidthisapproximatelyT=0.
67RTCT,whereRTandCTarearesistorandcapacitorfromRC-BRAKEtoground.
RecommendedvaluesforRTare10kto500k,andrecommendedvaluesforCTare1nFto100nF,allowingtimesbetween5μsand10ms.
Bestaccuracyandstabilityareachievedwithvaluesinthecentersofthoseranges.
RC-BRAKEalsohasanotherfunction.
IfRC-BRAKEpinispulledbelowthebrakethreshold,RC-BRAKE21thedeviceentersbrakemode.
Thismodeconsistsofturningoffallthreehigh-sidedevices,enablingallthreelow-sidedevices,anddisablingthetachometer.
Theonlythingsthatinhibitlow-sidedeviceoperationinbrakingarelow-supply,exceedingpeakcurrent,OV-COASTcommand,andthePWMcomparatorsignal.
Thelastofthesemeansthatifcurrentsenseisimplementedsuchthatthesignalinthecurrentsenseamplifierisproportionaltobrakingcurrent,thelow-sidedeviceswillbrakethemotorwithcurrentcontrol.
(Seeapplications)Simplercurrentsenseconnectionsresultsinuncontrolledbrakingandpotentialdamagetothepowerdevices.
TheUC1625canregulatemotorcurrentusingfixed-frequencypulsewidthmodulation(PWM).
TheRC-OSCpinsetsoscillatorfrequencybymeansoftimingresistorROSCfromtheRC-OSCpintoVREFandcapacitorCOSCfromRC-OSCtoGnd.
Resistors10kto100kandcapacitors1nFto100nFworksthebest,butfrequencyshouldalwaysbebelow500kHz.
Oscillatorfrequencyisapproximately:F=2/(ROSCxCOSC)RC-OSC25Additionalcomponentscanbeaddedtothisdevicetocauseittooperateasafixedoff-timePWMratherthanafixedfrequencyPWM,usingtheRC-OSCpintoselectthemonostabletimeconstant.
ThevoltageontheRC-OSCpinisnormallyarampofabout1.
2Vpeak-to-peak,centeredatapproximately1.
6V.
Thisrampcanbeusedforvoltage-modePWMcontrol,orcanbeusedforslopecompensationincurrent-modecontrol.
8SubmitDocumentationFeedbackCopyright2011,TexasInstrumentsIncorporatedProductFolderLink(s):UC1625-SPUC1625-SPwww.
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comSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011TerminalFunctions(continued)TERMINALDESCRIPTIONNAMENO.
AnytimethatVCCdropsbelowthresholdorthesensedcurrentexceedstheover-currentthreshold,thesoft-startlatchisset.
Whenset,itturnsonatransistorthatpullsdownonSSTART.
Normally,acapacitorisconnectedtothispin,andthetransistorwillcompletelydischargethecapacitor.
AcomparatorsenseswhentheNPNtransistorhascompletelydischargedthecapacitor,andallowsthesoft-startlatchtoclearwhenthefaultisremoved.
Whenthefaultisremoved,thesoft-startcapacitorchargesfromtheon-chipcurrentsource.
SSTARTclampstheoutputoftheerroramplifier,notallowingtheerroramplifieroutputSSTART24voltagetoexceedSSTARTregardlessofinput.
TheramponRC-OSCcanbeappliedtoPWMInandcomparedtoE/AOUT.
WithSSTARTdischargedbelow0.
2Vandtherampminimumbeingapproximately1.
0V,thePWMcomparatorkeepsthePWMlatchclearedandtheoutputsoff.
AsSSTARTrises,thePWMcomparatorbeginstoduty-cyclemodulatethePWMlatchuntiltheerroramplifierinputsovercometheclamp.
Thisprovidesforasafeandorderlymotorstart-upfromanofforfaultcondition.
A51-kresisterisaddedbetweenVREFandSSTARTtoensureswitching.
AnychangeintheH1,H2,orH3inputsloadsdatafromtheseinputsintothepositionsensorlatches.
Atthesametimedataisloaded,afixed-width5-VpulseistriggeredonTACH-OUT.
TheaveragevalueofthevoltageonTACH-OUTisdirectlyproportionaltospeed,sothisoutputcanbeusedasatruetachometerforspeedfeedbackwithanexternalfilterorTACH-OUT20averagingcircuitwhichusuallyconsistsofaresistorandcapacitor.
WheneverTACH-OUTishigh,thepositionlatchesareinhibited,suchthatduringthenoisiestpartofthecommutationcycle,additionalcommutationsarenotpossible.
Althoughthiseffectivelysetsamaximumrotationalspeed,themaximumspeedcanbesetabovethehighestexpectedspeed,preventingfalsecommutationandchatter.
Thisdeviceoperateswithsuppliesbetween10Vand18V.
Under-voltagelockoutkeepsalloutputsoffbelow7.
5V,insuringthattheoutputtransistorsneverturnonuntilfulldriveVCC19capabilityisavailable.
BypassVCCtogroundwithan0.
1-μFceramiccapacitor.
Usinga10-μFelectrolyticbypasscapacitoraswellcanbebeneficialinapplicationswithhighsupplyimpedance.
Thispinprovidesregulated5VfordrivingHall-effectdevicesandspeedcontrolcircuitry.
VREFreaches5VbeforeVCCenables,ensuringthatHall-effectdevicespoweredfromVREF2VREFbecomesactivebeforetheUC1625drivesanyoutput.
ForproperperformanceVREFshouldbebypassedwithatleasta0.
1-μFcapacitortoground.
TYPICALCHARACTERISTICSOscillatorFrequencyTachometeronTimevsvsCOSCandROSCRTandCTFigure2.
Figure3.
Copyright2011,TexasInstrumentsIncorporatedSubmitDocumentationFeedback9ProductFolderLink(s):UC1625-SPUC1625-SPSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011www.
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comTYPICALCHARACTERISTICS(continued)SupplyCurrentSoft-StartPullupCurrentvsvsTemperatureTemperatureFigure4.
Figure5.
Soft-StartDischargeCurrentCurrentSenseAmplifierTransferFunctionvsvsTemperatureISENSE2–ISENSE1Figure6.
Figure7.
10SubmitDocumentationFeedbackCopyright2011,TexasInstrumentsIncorporatedProductFolderLink(s):UC1625-SPUC1625-SPwww.
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comSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011APPLICATIONINFORMATIONCrossConductionPreventionTheUC1625insertsdelaystopreventcrossconductionduetooverlappingdrivesignals.
However,somethoughtmustalwaysbegiventocrossconductioninoutputstagedesignbecausenoamountofdeadtimecanpreventfastslewingsignalsfromcouplingdrivetoapowerdevicethroughaparasiticcapacitance.
TheUC1625containsinputlatchesthatserveasnoiseblankingfilters.
Theselatchesremaintransparentthroughanyphaseofamotorrotationandlatchimmediatelyafteraninputtransitionisdetected.
TheyremainlatchedfortwocyclesofthePWMoscillator.
AtaPWMoscillatorspeedof20kHz,thiscorrespondsto50μsto100μsofblanktimewhichlimitsmaximumrotationalspeedto100kRPMforamotorwithsixtransitionsperrotationor50kRPMforamotorwith12transitionsperrotation.
Thispreventsnoisegeneratedinthefirst50μsofatransitionfrompropagatingtotheoutputtransistorsandcausingcross-conductionorchatter.
TheUC1625alsocontainssixflipflopscorrespondingtothesixoutputdrivesignals.
Oneoftheseflipflopsisseteverytimethatanoutputdrivesignalisturnedon,andclearedtwoPWMoscillatorcyclesafterthatdrivesignalisturnedoff.
Theoutputofeachflipflopisusedtoinhibitdrivetotheopposingoutput(Figure8).
Inthisway,itisimpossibletoturnondriverPUAandPDAatthesametime.
ItisalsoimpossibleforoneofthesedriverstoturnonwithouttheotherdriverhavingbeenoffforatleasttwoPWMoscillatorclocks.
Figure8.
CrossConductionPreventionCopyright2011,TexasInstrumentsIncorporatedSubmitDocumentationFeedback11ProductFolderLink(s):UC1625-SPUC1625-SPSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011www.
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comPowerStageDesignTheUC1625isusefulinawidevarietyofapplications,includinghigh-powerinroboticsandmachinery.
Thepoweroutputstagesusedinsuchequipmentcantakeanumberofforms,accordingtotheintendedperformanceandpurposeofthesystem.
Figure9showfourdifferentpowerstageswiththeadvantagesanddisadvantagesofeach.
Forhigh-frequencychopping,fastrecoverycirculatingdiodesareessential.
Sixarerequiredtoclampthewindings.
Thesediodesshouldhaveacontinuouscurrentratingatleastequaltotheoperatingmotorcurrent,sincediodeconductionduty-cyclecanbehigh.
Forlow-voltagesystems,Schottkydiodesarepreferred.
Inhighervoltagesystems,diodessuchasMicrosemiUHVPhighvoltageplatinumrectifiersarerecommended.
Inapulse-by-pulsecurrentcontrolarrangement,currentsensingisdonebyresistorRS,throughwhichthetransistor'scurrentsarepassed(Fig.
A,B,andC).
Inthesecases,RDisnotneeded.
Thelow-sidecirculatingdiodesgotogroundandthecurrentsenseterminalsoftheUC1625(ISENSE1andISENSE2)areconnectedtoRSthroughadifferentialRCfilter.
Theinputbiascurrentofthecurrentsenseamplifiercausesacommonmodeoffsetvoltagetoappearatbothinputs,soforbestaccuracy,keepthefilterresistorsbelow2kandmatched.
ThecurrentthatflowsthroughRSisdiscontinuousbecauseofchopping.
Itflowsduringtheontimeofthepowerstageandiszeroduringtheofftime.
Consequently,thevoltageacrossRSconsistsofaseriesofpulses,occurringatthePWMfrequency,withapeakvalueindicativeofthepeakmotorcurrent.
Tosenseaveragemotorcurrentinsteadofpeakcurrent,addanothercurrentsenseresistor(RDinFig.
D)tomeasurecurrentinthelow-sidecirculatingdiodes,andoperateinfourquadrantmode(pin22high).
ThenegativevoltageacrossRDiscorrectedbytheabsolutevaluecurrentsenseamplifier.
WithinthelimitationsimposedbyTable2,thecircuitofFig.
Bcanalsosenseaveragecurrent.
12SubmitDocumentationFeedbackCopyright2011,TexasInstrumentsIncorporatedProductFolderLink(s):UC1625-SPUC1625-SPwww.
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comSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011Figure9.
FourPowerStageDesignsTable2.
ImposedLimitationsforFigure9CURRENTSENSESAFE2QUADRANT4QUADRANTPOWERREVERSEBRAKINGPulse-by-PulseAverageFigureAYesNoNoN0YesNoFigureBYesYesNoIn4-quadmodeonlyYesYesFigureCYesYesYesIn4-quadmodeonlyYesNoFigureDYesYesYesIn4-quadmodeonlyYesYesCopyright2011,TexasInstrumentsIncorporatedSubmitDocumentationFeedback13ProductFolderLink(s):UC1625-SPUC1625-SPSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011www.
ti.
comFordriveswherespeediscritical,P-channelMOSFETscanbedrivenbyemitterfollowersasshowninFigure10.
Here,boththelevelshiftNPNandthePNPmustwithstandhighvoltages.
Azenerdiodeisusedtolimitgate-sourcevoltageontheMOSFET.
Aseriesgateresistorisnotnecessary,butalwaysadvisabletocontrolovershootandringing.
High-voltageoptocouplerscanquicklydrivehigh-voltageMOSFETsifaboostsupplyofatleast10Vgreaterthanthemotorsupplyisprovided(SeeFigure11)ToprotecttheMOSFET,theboostsupplyshouldnotbehigherthan18Vabovethemotorsupply.
Forunder200-V2-quadrantapplications,apowerNPNdrivenbyasmallP-ChannelMOSFETperformswellasahigh-sidedriverasinFigure12.
Ahighvoltagesmall-signalNPNisusedasalevelshiftandahighvoltagelow-currentMOSFETprovidesdrive.
AlthoughtheNPNdoesnotsaturateifusedwithinitslimitations,thebase-emitterresistorontheNPNisstillthespeed-limitingcomponent.
Figure13showsapowerNPNDarlingtondrivetechniqueusingaclamptopreventdeepsaturation.
Bylimitingsaturationofthepowerdevice,excessivebasedriveisminimizedandturn-offtimeiskeptfairlyshort.
Lackofbaseseriesresistancealsoaddstothespeedofthisapproach.
Figure10.
FastHigh-SideP-ChannelDriverFigure11.
OptocoupledN-ChannelHigh-SideDriver14SubmitDocumentationFeedbackCopyright2011,TexasInstrumentsIncorporatedProductFolderLink(s):UC1625-SPUC1625-SPwww.
ti.
comSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011Figure12.
PowerNPNHigh-SideDriverFigure13.
PowerNPNLow-SideDriverCopyright2011,TexasInstrumentsIncorporatedSubmitDocumentationFeedback15ProductFolderLink(s):UC1625-SPUC1625-SPSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011www.
ti.
comFastHigh-SideN-ChannelDriverwithTransformerIsolationAsmallpulsetransformercanprovideexcellentisolationbetweentheUC1625andahigh-voltageN-ChannelMOSFETwhilealsocouplinggatedrivepower.
Inthiscircuit(showninFigure14),aUC3724isusedasatransformerdriver/encoderthatduty-cyclemodulatesthetransformerwitha150-kHzpulsetrain.
TheUC3725rectifiesthispulsetrainforgatedrivepower,demodulatesthesignal,anddrivesthegatewithover2-Apeakcurrent.
Figure14.
FastHigh-SideN-ChannelDriverwithTransformerIsolationBoththeUC3724andtheUC3725canoperateupto500kHzifthepulsetransformerisselectedappropriately.
Toraisetheoperatingfrequency,eitherlowerthetimingresistoroftheUC3724(1kmin),lowerthetimingcapacitoroftheUC3724(500pFmin)orboth.
Ifthereissignificantcapacitancebetweentransformerprimaryandsecondary,togetherwithveryhighoutputslewrate,thenitmaybenecessarytoaddclampdiodesfromthetransformerprimaryto12Vandground.
Generalpurposesmallsignalswitchingdiodessuchas1N4148arenormallyadequate.
TheUC3725alsohasprovisionsforMOSFETcurrentlimiting.
SeetheUC3725datasheetformoreinformationonimplementingthis.
16SubmitDocumentationFeedbackCopyright2011,TexasInstrumentsIncorporatedProductFolderLink(s):UC1625-SPUC1625-SPwww.
ti.
comSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011ComputationalTruthTableTable3showstheoutputsofthegatedriveandopencollectoroutputsforgivenhallinputcodesanddirectionsignals.
Numbersatthetopofthecolumnsarepinnumbers.
Thesedevicesoperatewithpositionsensorencodingthathaseitheroneortwosignalshighatatime,neverallloworallhigh.
Thiscodingissometimesreferredtoas"120°Coding"becausethecodingisthesameascodingwithpositionsensorsspaced120magneticdegreesabouttherotor.
Inresponsetothesepositionsensesignals,onlyonelow-sidedriverturnson(gohigh)andonehigh-sidedriverturnson(pulllow)atanytime.
Table3.
ComputationalTruthTableINPUTSOUTPUTSDIRH1H2H3Low-SideHigh-Side689101213141617181001LHLLHH1011LLHLHH1010LLHHLH1110HLLHLH1100HLLHHL1101LHLHHL0101LLHHLH0100LLHLHH0110LHLLHH0010LHLHHL0011HLLHHL0001HLLHLHX111LLLHHHX000LLLHHHCopyright2011,TexasInstrumentsIncorporatedSubmitDocumentationFeedback17ProductFolderLink(s):UC1625-SPUC1625-SPSLUSAG8A–SEPTEMBER2011–REVISEDSEPTEMBER2011www.
ti.
comFigure15.
45-V/8-ABrushlessDCMotorDriveCircuitN-ChannelpowerMOSFETsareusedforlow-sidedrivers,whileP-ChannelpowerMOSFETsareshownforhigh-sidedrivers.
ResistorsareusedtolevelshifttheUC1625open-collectoroutputs,drivingemitterfollowersintotheMOSFETgate.
A12-VzenerclampinsuresthattheMOSFETgate-sourcevoltageneverexceeds12V.
Series10-gateresistorstamegatereactance,preventingoscillationsandminimizingringing.
Theoscillatortimingcapacitorshouldbeplacedclosetopins15and25,tokeepgroundcurrentoutofthecapacitor.
Groundcurrentinthetimingcapacitorcausesoscillatordistortionandslavingtothecommutationsignal.
Thepotentiometerconnectedtopin1controlsPWMdutycycledirectly,implementingacrudeformofspeedcontrol.
Thiscontrolisoftenreferredtoas"voltagemode"becausethepotentiometerpositionsetstheaveragemotorvoltage.
Thiscontrolsspeedbecausesteady-statemotorspeediscloselyrelatedtoappliedvoltage.
Pin20(Tach-Out)isconnectedtopin7(SPEEDIN)throughanRCfilter,preventingdirectionreversalwhilethemotorisspinningquickly.
Intwo-quadrantoperation,thisreversalcancausekineticenergyfromthemotortobeforcedintothepowerMOSFETs.
Adiodeinserieswiththelow-sideMOSFETsfacilitatesPWMcurrentcontrolduringbrakingbyinsuringthatbrakingcurrentwillnotflowbackwardsthroughlow-sideMOSFETs.
Dualcurrent-senseresistorsgivecontinuouscurrentsense,whetherbrakingorrunninginfour-quadrantoperation,anunnecessaryluxuryfortwo-quadrantoperation.
The68-kand3-nFtachometercomponentssetmaximumcommutationtimeat140μs.
Thispermitssmoothoperationupto35,000RPMforfour-polemotors,yetgives140μsofnoiseblankingaftercommutation.
18SubmitDocumentationFeedbackCopyright2011,TexasInstrumentsIncorporatedProductFolderLink(s):UC1625-SPPACKAGEOPTIONADDENDUMwww.
ti.
com14-Feb-2021Addendum-Page1PACKAGINGINFORMATIONOrderableDeviceStatus(1)PackageTypePackageDrawingPinsPackageQtyEcoPlan(2)Leadfinish/Ballmaterial(6)MSLPeakTemp(3)OpTemp(°C)DeviceMarking(4/5)Samples5962-9168902VYAACTIVECDIPSBJDJ281Non-RoHS&GreenCallTIN/AforPkgType-55to1255962-9168902VYAUC1625-SP(1)Themarketingstatusvaluesaredefinedasfollows:ACTIVE:Productdevicerecommendedfornewdesigns.
LIFEBUY:TIhasannouncedthatthedevicewillbediscontinued,andalifetime-buyperiodisineffect.
NRND:Notrecommendedfornewdesigns.
Deviceisinproductiontosupportexistingcustomers,butTIdoesnotrecommendusingthispartinanewdesign.
PREVIEW:Devicehasbeenannouncedbutisnotinproduction.
Samplesmayormaynotbeavailable.
OBSOLETE:TIhasdiscontinuedtheproductionofthedevice.
(2)RoHS:TIdefines"RoHS"tomeansemiconductorproductsthatarecompliantwiththecurrentEURoHSrequirementsforall10RoHSsubstances,includingtherequirementthatRoHSsubstancedonotexceed0.
1%byweightinhomogeneousmaterials.
Wheredesignedtobesolderedathightemperatures,"RoHS"productsaresuitableforuseinspecifiedlead-freeprocesses.
TImayreferencethesetypesofproductsas"Pb-Free".
RoHSExempt:TIdefines"RoHSExempt"tomeanproductsthatcontainleadbutarecompliantwithEURoHSpursuanttoaspecificEURoHSexemption.
Green:TIdefines"Green"tomeanthecontentofChlorine(Cl)andBromine(Br)basedflameretardantsmeetJS709Blowhalogenrequirementsof<=1000ppmthreshold.
Antimonytrioxidebasedflameretardantsmustalsomeetthe<=1000ppmthresholdrequirement.
(3)MSL,PeakTemp.
-TheMoistureSensitivityLevelratingaccordingtotheJEDECindustrystandardclassifications,andpeaksoldertemperature.
(4)Theremaybeadditionalmarking,whichrelatestothelogo,thelottracecodeinformation,ortheenvironmentalcategoryonthedevice.
(5)MultipleDeviceMarkingswillbeinsideparentheses.
OnlyoneDeviceMarkingcontainedinparenthesesandseparatedbya"~"willappearonadevice.
IfalineisindentedthenitisacontinuationofthepreviouslineandthetwocombinedrepresenttheentireDeviceMarkingforthatdevice.
(6)Leadfinish/Ballmaterial-OrderableDevicesmayhavemultiplematerialfinishoptions.
Finishoptionsareseparatedbyaverticalruledline.
Leadfinish/Ballmaterialvaluesmaywraptotwolinesifthefinishvalueexceedsthemaximumcolumnwidth.
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