2023年高性能电流模式PWM控制器MXT7111

千里之行，始于足下让知识带有温度。第第2页/共2页精品文档推荐高性能电流模式PWM控制器MXT7111MXT7111isofferedinSOT23-6packages.MXT7111offerscompleteprotectioncoveragewithconverterapplicationsinsub36Wrange.MXT7111.AlargevalueresistMXT7111isahighlyint

CurrentModePWMPowerSwitch

ProductSpecification

FreqShuffling

GENERALDESCRIPTION

egratedcurrentmodePWMcontrolICoptimizedforhighperformance,lowstandbypowerandcosteffectiveofflineflybackPWMswitchingfrequencyatnormaloperationisexternallyprogrammableandtrimmedtotightrange.

Atnoloadorlightloadcondition,theICoperatesinextended‘burstmode’tominimizeswitchingloss.Lowerstandbypowerandhigherconversionefficiencyisthusachieved.

VDDlowstartupcurrentandlowoperatingcurrentcontributetoareliablepoweronstartupdesignwithorcouldthusbeusedinthestartupcircuittominimizethestandbypower.TheinternalslopecompensationimprovessystemlargesignalstabilityandreducesthepossiblesubharmonicoscillationathighPWMdutycycleoutput.

Leading-edgeblankingoncurrentsense(CS)inputremovesthesignalglitchduetosnubbercircuitdiodereverserecoveryandthusgreatlyreducestheexternalcomponentcountandsystemcostinthedesign.

automaticself-recoveryfeatureincludingCycle-by-Cyclecurrentlimiting(OCP),overloadprotection(OLP),VDDovervoltageclampandundervoltagelockout(UVLO).TheGate-driveoutputisclampedtomaximum18VtoprotectthepowerMOSFET.ExcellentEMIperformanceisachievedwithPower-Sourceproprietaryfrequencyshufflingtechniquetogetherwithsoftswitchingcontrolatthetotempolegatedriveoutput.

Toneenergyatbelow20KHZisminimizedinthe

designandaudionoiseiseliminatedduringoperation.

FEATURES

■Level5compliancewith<100mWstandbypoweratuniversalACinput.

■PowerSourceProprietaryFrequencyShufflingTechnologyforImprovedEMIPerformance.■ExtendedBurstModeControlForImprovedEfficiencyandMinimumStandbyPowerDesign■AudioNoiseFreeOperation

■ExternalProgrammablePWMSwitchingFrequency

■InternalSynchronizedSlopeCompensation■LowVDDStartupCurrentandLowOperatingCurrent(1.4mA)

■LeadingEdgeBlankingonCurrentSenseInput■GoodProtectionCoverageWithAutoSelf-Recovery

oVDDOverVoltageClampandUnderVoltageLockoutwithHysteresis(UVLO)

oGateOutputMaximumVoltageClamp(18V)oPowerSourceProprietaryLineInput

CompensatedCycle-by-CycleOver-currentThresholdSetting

ForConstantOutputPowerLimitingOverUniversalInputVoltageRange.oOverloadProtection(OLP)

APPLICATIONS

OfflineAC/DCflybackconverterfor■BatteryCharger■PowerAdaptor

■Set-TopBoxPowerSupplies■Open-frameSMPS

TYPICALAPPLICATION

MXT7111

7111:ProductNameX:LotNumberCode

TheMXT7111isofferedinSOT23-6packages,

GENERALINFORMATION

PinConfiguration

shownasbelow.

PackageDissipationRatingPackageRθJA(℃/W)

SOT23-6200

AbsoluteMaximumRatingsParameterValueVDDDCSupplyVoltage30VVDDZenerClamp

VoltageNote

VDD_Clamp+0.1V

VDDDCClampCurrent10mAVFBInputVoltage-0.3to7VVSENSEInputVoltageto

SensePin

-0.3to7V

VRIInputVoltagetoRI

Pin

-0.3to7V

Min/MaxOperating

JunctionTemperatureTJ-20to150oC

Min/MaxStorage

TemperatureTstg

-55to160oC

Note:VDD_Clamphasanominalvalueof34V.

Stressesbeyondthoselistedunder“absolutemaximumratings”maycausepermanentdamagetothedevice.Thesearestressratingsonly,functionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedunder“recommendedoperatingconditions”isnotimplied.Exposuretoabsolute

maximum-ratedconditionsforextendedperiodsmayaffectdevicereliability.

MarkingInformation

TERMINALASSIGNMENTS

PinNameI/ODescriptionGNDPGround

FBI

Feedbackinputpin.ThePWMdutycycleisdetermainedbyvoltagelevelinto

thispinandSENSEpininput.

RII

InternalOscillatorfrequencysettingpin.AresistorconnectedbetweenRIand

GNDsetsthePWMfrequency.

SENSEICurrentsenseinputpin.ConnectedtoMOSFETcurrentsensingresistornode.VDDPChipDCpowersupplypin.GATEOTotem-polegatedriveoutputforthepowerMOSFET.

GNDFBRI

SENSE

VDDGATECurrentModePWMPowerSwitch

ProductSpecification

FreqShuffling

S:Package

RECOMMENDEDOPERATINGCONDITION

UnitSymbolParameterMin/Max

VDDVDDSupplyVoltage10to30V

RIRIResistorValue100Kohm

TAOperationAmbientTemperature-20to85℃

BLOCKDIAGRAM

ELECTRICALCHARACTERISTICS

(TA=25℃ifnototherwisenoted)

SymbolParameterTestConditionsMinTypMaxUnitSupplyVoltage(VDD)

I_VDD_StartupVDDStartup

Current

VDD=12.5V,RI=100K

MeasureLeakagecurrentintoVDD320uA

I_VDD_OpsOperationCurrentVDD=16V,RI=100K,

VFB=3V

1.4mA

UVLO(ON)VDDUnderVoltage

LockoutEnter

6.2

7.2

8.2V

UVLO(OFF)VDDUnderVoltage

LockoutExit

(Recovery)

131415VVDD_ClampVDDZenerClamp

Voltage

IVDD=5mA

34VFeedbackInputSection(FBPin)

AVCSPWMInputGain

△VFB/△VCS2.0V/VVFB_OpenVFBOpenLoop

Voltage

4.8V

IFB_ShortFBpinshortcircuitcurrentShortFBpintoGND

andmeasurecurrent1.0mA

VTH_0DZeroDutyCycleFB

ThresholdVoltageVDD=16V,RI=100K0.75V

VTH_PLPowerLimitingFB

ThresholdVoltage3.7V

TD_PLPowerLimiting

DebounceTime

35mSec

ZFB_INInputImpedance6Kohm

DC_MAXMaximumDutyCycleVDD=18V,RI=100K,

FB=3V,CS=0V

75%

CurrentSenseInput(SensePin)

T_blankingLeadingedge

blankingtime

RI=100K300ns

ZSENSE_INInputImpedance40Kohm

TD_OCOverCurrent

Detectionand

ControlDelayVDD=16V,

CS＞VTH_OC,FB=3.3V

75nSecVTH_OCOverCurrent

ThresholdVoltageat

zeroDutyCycle

FB=3.3V,RI=100K0.700.750.80VOscillator

FOSCNormalOscillation

FrequencyRI=100K606570KHz

△f_TempFrequency

Temperature

Stability

VDD=16V,RI=100K,

TA-20℃to100℃

5%△f_VDDFrequencyVoltage

Stability

VDD=12-25V,RI=100K5%

RI_rangeOperatingRIRange50100150KohmV_RI_openRIopenloadvoltage2V

FOSC_BMBurstModeBase

Frequency

VDD=16V,RI=100K22KHz

SymbolParameterTest

ConditionsMin

Typ

Max

UnitGateDriveOutput

VOLOutputLowLevelVDD=16V,IO

=-20mA0.8VVOHOutputHighLevelVDD=16V,IO

=20mA10V

V_ClampOutputClamp

VoltageLevel

18

V

T_rOutputRisingTimeVDD=16V,CL=1nF220nSecT_fOutputFallingTimeVDD=16V,CL=1nF70nSecFrequencyShuffling

△f_OSCFrequency

Modulationrange

/BaseFrequency

RI

=100K-3

3

%

f_shufflingShuffling

FrequencyRI=100K64Hz

CHARACTERIZATIONPLOTS

VDD=16V,RI=100Kohm,TA=25℃conditionappliesifnototherwisenoted.

applicationsinsub36Wpowerrange.Theextended

TheMXT7111isahighlyin

OPERATIONDESCRIPTION

tegratedPWMcontroller

ICoptimizedforofflineflybackconverterburstmodecontrolgreatlyreducesthestandbypower

consumptionandhelpsthedesigneasilymeettheinternationalpowerconservationrequirements.

?StartupCurrentandStartupControl

sothatVDDcouldbechargedupaboveUVLOthresholdlevelanddevicestartsupquickly.Alarge

valuestartupresistorcanthereforebeusedtominimizethepowerlossyetprovidesreliablestartup

inapplication.ForAC/DCadaptorwithuniversal

inputrangedesign,a2M?,1/8WstartupresistorcouldbeusedtogetherwithaVDDcapacitorto

provideafaststartupandlowpowerdissipationsolution.

?OperatingCurrentoperatingcurrenttogetherwithextendedburstmodecontrolfeatures.?FrequencyshufflingforEMIimprovementThefrequencyShuffling/jittering(switchingTheoscillationfrequencyismodulatedwitharandomsourcesothatthetoneenergyisspreadout.ThespreadspectrumminimizestheconductionbandEMIandthereforereducessystemdesignchallenge.?ExtendedBurstModeOperationAtzeroloadorlightloadcondition,majorityofthepowerdissipationinaswitchingmodepowersupplyisfromswitchinglossontheMOSFETtransistor,thecorelossofthetransformerandthelossonthesnubbercircuit.Themagnitudeofpowerlossisin

proportiontothenumberofswitchingeventswithinafixedperiodoftime.Reducingswitchingeventsleadstothereductiononthepowerlossandthusconservestheenergy.theloadingcondition.Atfromnoloadtolight/mediumloadcondition,theFBinputdropsbelowburstmodethresholdlevel.DeviceentersBurstModecontrol.TheGatedriveoutputswitchesonlywhenVDDvoltagedropsbelowapresetlevelandFBinputisactivetooutputanonstate.Otherwisethegatedriveremainsatoffstatetominimizethe

switchinglossandreducesthestandbypowerconsumptiontothegreatestextend.Thefrequency

controlalsoeliminatestheaudionoiseatanyloadingconditions.

?OscillatorOperationAresistorconnectedbetweenRIandGNDsetstheconstantcurrentsourcetocharge/dischargetheinternalcapandthusthePWMoscillatorfrequencyisdetermined.TherelationshipbetweenRIand

switchingfrequencyfollowsthebelowequationwithinthespecifiedRIinKohmrangeatnominal

loadingoperationalcondition.6500()(ohm)

OSCFKHzRIK

?CurrentSensingandLeadingEdgeBlankingCycle-by-Cyclecurrentlimitingisofferedin

currentisdetectedbyasenseresistorintothesense

pin.Aninternalleadingedgeblankingcircuitchops

offthesensevoltagespikeatinitialMOSFETonstate

duetoSnubberdiodereverserecoverysothattheexternalRCfilteringonsenseinputisnolonger

required.ThecurrentlimitcomparatorisdisabledandthuscannotturnofftheexternalMOSFETduringtheblankingperiod.PWMdutycycleisdeterminedbythecurrentsenseinputvoltageandtheFBinput

voltage.?InternalSynchronizedSlopeCompensationBuilt-inslopecompensationcircuitaddsvoltageramp

ontothecurrentsenseinputvoltageforPWMgeneration.ThisgreatlyimprovesthecloseloopstabilityatCCMandpreventsthesub-harmonicoscillationandthusreducestheoutputripplevoltage.

?GateDrivegateforpowerswitchcontrol.TooweakthegatedrivestrengthresultsinhigherconductionandswitchlossofMOSFETwhiletoostronggatedriveoutputcompromisestheEMI.

Agoodtradeoffisachievedthroughthebuilt-intotempolegatedesignwithrightoutputstrengthanddeadtimecontrol.ThelowidlelossandgoodEMIsystemdesigniseasiertoachievewiththisdedicatedcontrolscheme.Aninternal18VclampisaddedforMOSFETgateprotectionathigherthanexpectedVDDinput.

CurrentModePWMPowerSwitchProductSpecification

FreqShuffling

StartupcurrentofMXT7111isdesignedtobeverylow

TheOperatingcurrentofMXT7111islowat1.4mA.frequencymodulation)isimplementedinMXT7111.

MXT7111selfadjuststheswitchingmodeaccordingto

GoodefficiencyisachievedwithMXT7111low

MXT7111currentmodePWMcontrol.Theswitch

MXT7111GateisconnectedtoanexternalMOSFET

?ProtectionControls

GoodpowersupplysystemreliabilityisachievedwithitsrichprotectionfeaturesincludingCycle-by-Cyclecurrentlimiting(OCP),OverLoadProtection(OLP)andovervoltageclamp,Under