1
FileNumber4275.2
HIP6004
BuckandSynchronous-Rectifier(PWM)
ControllerandOutputVoltageMonitor
TheHIP6004providescompletecontrolandprotectionfora
DC-DCconverteroptimizedforhigh-performance
microprocessorapplications.Itisdesignedtodrivetwo
N-ChannelMOSFETsinasynchronous-rectifiedbuck
topology.TheHIP6004integratesallofthecontrol,output
adjustment,monitoringandprotectionfunctionsintoasingle
package.
Theoutputvoltageoftheconverteriseasilyadjustedand
preciselyregulated.TheHIP6004includesa5-input
digital-to-analogconverter(DAC)thatadjuststheoutput
voltagefrom2.1V
DC
to3.5V
DC
in0.1Vincrementsandfrom
1.3V
DC
to2.1V
DC
in0.05Vsteps.Theprecisionreference
andvoltage-moderegulatorholdtheselectedoutputvoltage
towithin±1%overtemperatureandlinevoltagevariations.
TheHIP6004providessimple,singlefeedbackloop,
voltage-modecontrolwithfasttransientresponse.Itincludes
a200kHzfree-runningtriangle-waveoscillatorthatis
adjustablefrombelow50kHztoover1MHz.Theerror
amplifierfeaturesa15MHzgain-bandwidthproductand
6V/μsslewratewhichenableshighconverterbandwidthfor
fasttransientperformance.TheresultingPWMdutyratio
rangesfrom0%to100%.
TheHIP6004monitorstheoutputvoltagewithawindow
comparatorthattrackstheDACoutputandissuesaPower
Goodsignalwhentheoutputiswithin±10%.TheHIP6004
protectsagainstover-currentconditionsbyinhibitingPWM
operation.Built-inover-voltageprotectiontriggersan
externalSCRtocrowbartheinputsupply.TheHIP6004
monitorsthecurrentbyusingther
DS(ON)
oftheupper
MOSFETwhicheliminatestheneedforacurrentsensing
resistor.
AlphaMicro?isatrademarkofDigitalComputerEquipmentCorporation.
Pentium?isaregisteredtrademarkofIntelCorporation.
PowerPC?isaregisteredtrademarkofIBM.
Features
?DrivesTwoN-ChannelMOSFETs
?Operatesfrom+5Vor+12VInput
?SimpleSingle-LoopControlDesign
-Voltage-ModePWMControl
?FastTransientResponse
-High-BandwidthErrorAmplifier
-Full0%to100%DutyRatio
?ExcellentOutputVoltageRegulation
-±1%OverLineVoltageandTemperature
?5-BitDigital-to-AnalogOutputVoltageSelection
-WideRange...................1.3V
DC
to3.5V
DC
-0.1VBinarySteps...............2.1V
DC
to3.5V
DC
-0.05VBinaryStep...............1.3V
DC
to2.1V
DC
?Power-GoodOutputVoltageMonitor
?Over-VoltageandOver-CurrentFaultMonitors
-DoesNotRequireExtraCurrentSensingElement,
UsesMOSFETsr
DS(ON)
?SmallConverterSize
-ConstantFrequencyOperation
-200kHzFree-RunningOscillatorProgrammablefrom
50kHztoover1MHz
Applications
?
PowerSupplyforPentium?,PentiumPro,PowerPC?and
Alpha?Microprocessors
?
High-Power5Vto3.xVDC-DCRegulators
?
Low-VoltageDistributedPowerSupplies
Pinout
HIP6004
(SOIC)
TOPVIEW
OrderingInformation
PARTNUMBER
TEMP.
RANGE(
o
C)PACKAGE
PKG.
NO.
HIP6004CB0to7020LdSOICM20.3
Thisdatasheetdescribesapre-releasedproduct.
11
12
13
14
15
16
17
18
20
19
10
9
8
7
6
5
4
3
2
1VSEN
OCSET
SS
VID0
VID1
VID2
VID4
VID3
COMP
FB
RT
VCC
LGATE
PGND
OVP
BOOT
UGATE
PHASE
PGOOD
GND
DataSheetMarch2000
CAUTION:Thesedevicesaresensitivetoelectrostaticdischarge;followproperICHandlingProcedures.
1-888-INTERSILor321-724-7143|Copyright?IntersilCorporation2000
2
TypicalApplication
BlockDiagram
+12V
+V
OUT
PGND
HIP6004
VSEN
RT
FB
COMP
VID0
VID1
VID2
VID3
SS
PGOOD
D/A
GND
OSC
LGATE
UGATE
OCSET
PHASE
BOOT
EN
VCC
V
IN
=+5Vor+12V
OVP
MONITORAND
PROTECTION
+
-
+
-VID4
D/A
CONVERTER
(DAC)
OSCILLATOR
SOFT-
START
REFERENCE
POWER-ON
RESET(POR)
115%
110%
90%
INHIBIT
PWM
COMPARATOR
ERROR
AMP
VCC
PGOOD
SS
PWM
OVP
RT
GND
VSEN
OCSET
VID0
VID1
VID2
VID3
FB
COMP
DACOUT
OVER-
VOLTAGE
OVER-
CURRENT
GATE
CONTROL
LOGIC
BOOT
UGATE
PHASE
200μA
10μA
4V
+
-
+
-
+
-
+
-
+
-
+
-
VID4
LGATE
PGND
HIP6004
3
AbsoluteMaximumRatingsThermalInformation
SupplyVoltage,V
CC
................................+15V
BootVoltage,V
BOOT
-V
PHASE
........................+15V
Input,OutputorI/OVoltage...........GND-0.3VtoVCC+0.3V
ESDClassification.................................Class2
OperatingConditions
SupplyVoltage,V
CC
...........................+12V±10%
AmbientTemperatureRange.....................0
o
Cto70
o
C
JunctionTemperatureRange....................0
o
Cto125
o
C
ThermalResistance(Typical,Note1)θ
JA
(
o
C/W)
SOICPackage.............................118
MaximumJunctionTemperature(PlasticPackage)........150
o
C
MaximumStorageTemperatureRange..........-65
o
Cto150
o
C
MaximumLeadTemperature(Soldering10s).............300
o
C
(SOIC-LeadTipsOnly)
CAUTION:Stressesabovethoselistedin“AbsoluteMaximumRatings”maycausepermanentdamagetothedevice.Thisisastressonlyratingandoperationofthe
deviceattheseoranyotherconditionsabovethoseindicatedintheoperationalsectionsofthisspecificationisnotimplied.
NOTE:
1.θ
JA
ismeasuredwiththecomponentmountedonaloweffectivethermalconductivitytestboardinfreeair.SeeTechBrief379fordetails.
ElectricalSpecificationsRecommendedOperatingConditions,UnlessOtherwiseNoted
PARAMETERSYMBOLTESTCONDITIONSMINTYPMAXUNITS
VCCSUPPLYCURRENT
NominalSupplyI
CC
UGATEandLGATEOpen-5-mA
POWER-ONRESET
RisingVCCThresholdV
OCSET
=4.5V--10.4V
FallingVCCThresholdV
OCSET
=4.5V8.2--V
RisingV
OCSET
Threshold-1.26-V
OSCILLATOR
FreeRunningFrequencyRT=OPEN185200215kHz
TotalVariation6k?
RampAmplitude?V
OSC
RT=Open-1.9-V
P-P
REFERENCEANDDAC
DACOUTVoltageAccuracy-1.0-+1.0%
ERRORAMPLIFIER
DCGain-88-dB
Gain-BandwidthProductGBW-15-MHz
SlewRateSRCOMP=10pF-6-V/μs
GATEDRIVERS
UpperGateSourceI
UGATE
V
BOOT
-V
PHASE
=12V,V
UGATE
=6V350500-mA
UpperGateSinkR
UGATE
I
LGATE
=0.3A-5.510?
LowerGateSourceI
LGATE
VCC=12V,V
LGATE
=6V300450-mA
LowerGateSinkR
LGATE
I
LGATE
=0.3A-3.56.5?
PROTECTION
Over-VoltageTrip(V
SEN
/DACOUT)-115120%
OCSETCurrentSourceI
OCSET
V
OCSET
=4.5V
DC
170200230μA
OVPSourcingCurrentI
OVP
V
SEN
=5.5V,V
OVP
=0V60--mA
SoftStartCurrentI
SS
-10-μA
POWERGOOD
UpperThreshold(V
SEN
/DACOUT)VSENRising106-111%
LowerThreshold(V
SEN
/DACOUT)VSENFalling89-94%
Hysteresis(VSEN/DACOUT)UpperandLowerThreshold-2-%
PGOODVoltageLowV
PGOOD
I
PGOOD
=-5mA-0.5-V
HIP6004
4
FunctionalPinDescription
VSEN(Pin1)
Thispinisconnectedtotheconvertersoutputvoltage.The
PGOODandOVPcomparatorcircuitsusethissignalto
reportoutputvoltagestatusandforovervoltageprotection.
OCSET(Pin2)
Connectaresistor(R
OCSET
)fromthispintothedrainofthe
upperMOSFET.R
OCSET
,aninternal200μAcurrentsource
(I
OCS
),andtheupperMOSFETon-resistance(r
DS(ON)
)set
theconverterover-current(OC)trippointaccordingtothe
followingequation:
Anover-currenttripcyclesthesoft-startfunction.
SS(Pin3)
Connectacapacitorfromthispintoground.Thiscapacitor,
alongwithaninternal10μAcurrentsource,setsthesoft-
startintervaloftheconverter.
VID0-4(Pins4-8)
VID0-4aretheinputpinstothe5-bitDAC.Thestatesof
thesefivepinsprogramtheinternalvoltagereference
(DACOUT).ThelevelofDACOUTsetstheconverteroutput
voltage.ItalsosetsthePGOODandOVPthresholds.Table
1specifiesDACOUTforthe32combinationsofDACinputs.
COMP(Pin9)andFB(Pin10)
COMPandFBaretheavailableexternalpinsoftheerror
amplifier.TheFBpinistheinvertinginputoftheerror
amplifierandtheCOMPpinistheerroramplifieroutput.
Thesepinsareusedtocompensatethevoltage-control
feedbackloopoftheconverter.
GND(Pin11)
SignalgroundfortheIC.Allvoltagelevelsaremeasuredwith
respecttothispin.
PGOOD(Pin12)
PGOODisanopencollectoroutputusedtoindicatethe
statusoftheconverteroutputvoltage.Thispinispulledlow
whentheconverteroutputisnotwithin±10%ofthe
DACOUTreferencevoltage.
PHASE(Pin13)
ConnectthePHASEpintotheupperMOSFETsource.This
pinisusedtomonitorthevoltagedropacrosstheMOSFET
forover-currentprotection.Thispinalsoprovidesthereturn
pathfortheuppergatedrive.
UGATE(Pin14)
ConnectUGATEtotheupperMOSFETgate.Thispin
providesthegatedrivefortheupperMOSFET.
BOOT(Pin15)
ThispinprovidesbiasvoltagetotheupperMOSFETdriver.
AbootstrapcircuitmaybeusedtocreateaBOOTvoltage
suitabletodriveastandardN-ChannelMOSFET.
TypicalPerformanceCurves
FIGURE1.R
T
RESISTANCEvsFREQUENCYFIGURE2.BIASSUPPLYCURRENTvsFREQUENCY
101001000
SWITCHINGFREQUENCY(kHz)
RESIST
ANCE(k
?
)
10
100
1000
R
T
PULLUP
TO+12V
R
T
PULLDOWNTOV
SS
1002003004005006007008009001000
I
CC
(mA)
SWITCHINGFREQUENCY(kHz)
C
GATE
=3300pF
C
GATE
=1000pF
C
GATE
=10pF
C
UPPER
=C
LOWER
=C
GATE
80
70
60
50
40
30
20
10
0
11
12
13
14
15
16
17
18
20
19
10
9
8
7
6
5
4
3
2
1VSEN
OCSET
SS
VID0
VID1
VID2
VID4
VID3
COMP
FB
RT
VCC
LGATE
PGND
OVP
BOOT
UGATE
PHASE
PGOOD
GND
I
PEAK
I
OCS
R
OCSET
?
r
DSON()
--------------------------------------------=
HIP6004
5
PGND(Pin16)
Thisisthepowergroundconnection.TiethelowerMOSFET
sourcetothispin.
LGATE(Pin17)
ConnectLGATEtothelowerMOSFETgate.Thispin
providesthegatedriveforthelowerMOSFET.
VCC(Pin18)
Providea12Vbiassupplyforthechiptothispin.
OVP(Pin19)
TheOVPpincanbeusedtodriveanexternalSCRinthe
eventofanovervoltagecondition.
RT(Pin20)
Thispinprovidesoscillatorswitchingfrequencyadjustment.
Byplacingaresistor(R
T
)fromthispintoGND,thenominal
200kHzswitchingfrequencyisincreasedaccordingtothe
followingequation:
Conversely,connectingapull-upresistor(R
T
)fromthispin
toVCCreducestheswitchingfrequencyaccordingtothe
followingequation:
FunctionalDescription
Initialization
TheHIP6004automaticallyinitializesuponreceiptofpower.
Specialsequencingoftheinputsuppliesisnotnecessary.
ThePower-OnReset(POR)functioncontinuallymonitors
theinputsupplyvoltages.ThePORmonitorsthebias
voltageattheVCCpinandtheinputvoltage(V
IN
)onthe
OCSETpin.ThelevelonOCSETisequaltoV
IN
lessafixed
voltagedrop(seeover-currentprotection).ThePORfunction
initiatessoftstartoperationafterbothinputsupplyvoltages
exceedtheirPORthresholds.Foroperationwithasingle
+12Vpowersource,V
IN
andV
CC
areequivalentandthe
+12VpowersourcemustexceedtherisingV
CC
threshold
beforePORinitiatesoperation.
SoftStart
ThePORfunctioninitiatesthesoftstartsequence.Aninternal
10μAcurrentsourcechargesanexternalcapacitor(C
SS
)on
theSSpinto4V.Softstartclampstheerroramplifieroutput
(COMPpin)andreferenceinput(+terminaloferroramp)tothe
SSpinvoltage.Figure3showsthesoftstartintervalwith
C
SS
=0.1μF.Initiallytheclampontheerroramplifier(COMP
pin)controlstheconverter’soutputvoltage.Att
1
inFigure3,the
SSvoltagereachesthevalleyoftheoscillator’strianglewave.
Theoscillator’striangularwaveformiscomparedtotheramping
erroramplifiervoltage.ThisgeneratesPHASEpulsesof
increasingwidththatchargetheoutputcapacitor(s).This
intervalofincreasingpulsewidthcontinuestot
2
.Withsufficient
outputvoltage,theclamponthereferenceinputcontrolsthe
outputvoltage.Thisistheintervalbetweent
2
andt
3
inFigure3.
Att
3
theSSvoltageexceedstheDACOUTvoltageandthe
outputvoltageisinregulation.Thismethodprovidesarapid
andcontrolledoutputvoltagerise.ThePGOODsignaltoggles
‘high’whentheoutputvoltage(VSENpin)iswithin±5%of
DACOUT.The2%hysteresisbuiltintothepowergood
comparatorspreventsPGOODoscillationduetonominal
outputvoltageripple.
Over-CurrentProtection
Theover-currentfunctionprotectstheconverterfroma
shortedoutputbyusingtheupperMOSFETson-resistance,
r
DS(ON)
tomonitorthecurrent.Thismethodenhancesthe
converter’sefficiencyandreducescostbyeliminatinga
currentsensingresistor.
Theover-currentfunctioncyclesthesoft-startfunctionina
hiccupmodetoprovidefaultprotection.Aresistor(R
OCSET
)
programstheover-currenttriplevel.Aninternal200μAcurrent
sinkdevelopsavoltageacrossR
OCSET
thatisreferencedto
V
IN
.WhenthevoltageacrosstheupperMOSFET(also
Fs200kHz
510
6
?
R
T
k?()
---------------------+≈
(R
T
toGND)
Fs200kHz
410
7
?
R
T
k?()
---------------------–≈
(R
T
to12V)
0V
0V
0V
TIME(5ms/DIV.)
SOFT-START
(1V/DIV.)
OUTPUT
(1V/DIV.)
VOLTAGE
t
2
t
3
PGOOD
(2V/DIV.)
t
1
FIGURE3.SOFTSTARTINTERVAL
OUTPUTINDUCT
OR
SOFT
-ST
AR
T
0A
0V
TIME(20ms/DIV.)
5A
10A
15A
2V
4V
FIGURE4.OVER-CURRENTOPERATION
HIP6004
6
referencedtoV
IN
)exceedsthevoltageacrossR
OCSET
,the
over-currentfunctioninitiatesasoft-startsequence.Thesoft-
startfunctiondischargesC
SS
witha10μAcurrentsinkand
inhibitsPWMoperation.Thesoft-startfunctionrechargesC
SS
,
andPWMoperationresumeswiththeerroramplifierclamped
totheSSvoltage.Shouldanoverloadoccurwhilerecharging
C
SS
,thesoftstartfunctioninhibitsPWMoperationwhilefully
chargingC
SS
to4Vtocompleteitscycle.Figure4showsthis
operationwithanoverloadcondition.Notethattheinductor
currentincreasestoover15AduringtheC
SS
charginginterval
andcausesanover-currenttrip.Theconverterdissipatesvery
littlepowerwiththismethod.Themeasuredinputpowerforthe
conditionsofFigure4is2.5W.
Theover-currentfunctionwilltripatapeakinductorcurrent
(I
PEAK)
determinedby:
whereI
OCSET
istheinternalOCSETcurrentsource(200μA
typical).TheOCtrippointvariesmainlyduetotheMOSFETs
r
DS(ON)
variations.Toavoidover-currenttrippinginthe
normaloperatingloadrange,findtheR
OCSET
resistorfrom
theequationabovewith:
1.Themaximumr
DS(ON)
atthehighestjunctiontemperature.
2.TheminimumI
OCSET
fromthespecificationtable.
3.DetermineI
PEAK
for,
where?Iistheoutputinductorripplecurrent.
Foranequationfortheripplecurrentseethesectionunder
componentguidelinestitled‘OutputInductorSelection’.
Asmallceramiccapacitorshouldbeplacedinparallelwith
R
OCSET
tosmooththevoltageacrossR
OCSET
inthe
presenceofswitchingnoiseontheinputvoltage.
OutputVoltageProgram
TheoutputvoltageofaHIP6004converterisprogrammed
todiscretelevelsbetween1.3V
DC
and3.5V
DC
.The
voltageidentification(VID)pinsprogramaninternalvoltage
reference(DACOUT)witha5-bitdigital-to-analogconverter
(DAC).ThelevelofDACOUTalsosetsthePGOODand
OVPthresholds.Table1specifiestheDACOUTvoltagefor
the32combinationsofopenorshortconnectionsonthe
VIDpins.Theoutputvoltageshouldnotbeadjustedwhile
theconverterisdeliveringpower.Removeinputpower
beforechangingtheoutputvoltage.Adjustingtheoutput
voltageduringoperationcouldtogglethePGOODsignal
andexercisetheovervoltageprotection.
TheDACfunctionisaprecisionnon-invertingsummation
amplifiershowninFigure5.Theresistorvaluesshownare
onlyapproximationsoftheactualprecisionvaluesused.
GroundinganycombinationoftheVIDpinsincreasesthe
DACOUTvoltage.The‘open’circuitvoltageontheVIDpins
isthebandgapreferencevoltage,1.26V.
I
PEAK
I
OCSET
R
OCSET
?
r
DSON()
---------------------------------------------------=
I
PEAK
I
OUTMAX()
?I()2?+>
TABLE1.OUTPUTVOLTAGEPROGRAM
PINNAMENOMINAL
OUTPUT
VOLTAGE
DACOUT
PINNAMENOMINAL
OUTPUT
VOLTAGE
DACOUTVID4VID3VID2VID1VID0VID4VID3VID2VID1VID0
011111.30111112.0
011101.35111102.1
011011.40111012.
011001.45111002.3
010111.50110112.4
010101.55110102.5
010011.60110012.6
010001.65110002.7
001111.70101112.8
001101.75101102.9
001011.80101013.0
001001.85101003.1
000111.90100113.2
000101.95100103.
000012.00100013.4
000002.05100003.5
NOTE:0=connectedtoGNDorV
SS
,1=OPEN.
HIP6004
7
ApplicationGuidelines
LayoutConsiderations
Asinanyhighfrequencyswitchingconverter,layoutisvery
important.Switchingcurrentfromonepowerdevicetoanother
cangeneratevoltagetransientsacrosstheimpedancesofthe
interconnectingbondwiresandcircuittraces.These
interconnectingimpedancesshouldbeminimizedbyusing
wide,shortprintedcircuittraces.Thecriticalcomponents
shouldbelocatedasclosetogetheraspossible,usingground
planeconstructionorsinglepointgrounding.
Figure6showsthecriticalpowercomponentsofthe
converter.Tominimizethevoltageovershootthe
interconnectingwiresindicatedbyheavylinesshouldbe
partofgroundorpowerplaneinaprintedcircuitboard.The
componentsshowninFigure6shouldbelocatedasclose
togetheraspossible.PleasenotethatthecapacitorsC
IN
andC
O
eachrepresentnumerousphysicalcapacitors.
LocatetheHIP6004within3inchesoftheMOSFETs,Q1
andQ2.ThecircuittracesfortheMOSFETs’gateand
sourceconnectionsfromtheHIP6004mustbesizedto
handleupto1Apeakcurrent.
Figure7showsthecircuittracesthatrequireadditional
layoutconsideration.Usesinglepointandgroundplane
constructionforthecircuitsshown.Minimizeanyleakage
currentpathsontheSSPINandlocatethecapacitor,C
ss
closetotheSSpinbecausetheinternalcurrentsourceis
only10μA.ProvidelocalV
CC
decouplingbetweenVCCand
GNDpins.Locatethecapacitor,C
BOOT
ascloseaspractical
totheBOOTandPHASEpins.
FeedbackCompensation
Figure8highlightsthevoltage-modecontrolloopfora
synchronous-rectifiedbuckconverter.Theoutputvoltage
(V
OUT
)isregulatedtotheReferencevoltagelevel.Theerror
amplifier(ErrorAmp)output(V
E/A
)iscomparedwiththe
oscillator(OSC)triangularwavetoprovideapulse-width
modulated(PWM)wavewithanamplitudeofV
IN
atthe
PHASEnode.ThePWMwaveissmoothedbytheoutput
filter(L
O
andC
O
).
1.26V
VID3
VID2
VID1
VID0
COMP
DACOUT
ERROR
AMPLIFIER
2.7k?
1.7k?
5.4k?
10.7k?
21.5k?
2.9k?
DAC
VID4
3.6k?
12k?
12k?
BANDGAP
REFERENCE
+
-
FB
+
-
FIGURE5.DACFUNCTIONSCHEMATIC
PGND
L
O
C
OLGATE
UGATE
PHASE
Q1
Q2
D2
V
IN
V
OUT
RETURN
HIP6004
C
IN
LO
AD
FIGURE6.PRINTEDCIRCUITBOARDPOWERAND
GROUNDPLANESORISLANDS
FIGURE7.PRINTEDCIRCUITBOARDSMALLSIGNAL
LAYOUTGUIDELINES
+12V
HIP6004
SS
GND
VCC
BOOT
D1
L
O
C
O
V
OUT
LO
AD
Q1
Q2
PHASE
+V
IN
C
BOOT
C
VCC
C
SS
FIGURE8.VOLTAGE-MODEBUCKCONVERTER
COMPENSATIONDESIGN
V
OUT
OSC
REFERENCE
L
O
C
O
ESR
V
IN
?V
OSC
ERROR
AMP
PWM
DRIVER
(PARASITIC)
Z
FB
+
-
DACOUT
R1
R3R2
C3
C2
C1
COMP
V
OUT
FB
Z
FB
HIP6004
Z
IN
COMPARATOR
DRIVER
DETAILEDCOMPENSATIONCOMPONENTS
PHASE
V
E/A
+
-
+
-Z
IN
HIP6004
8
Themodulatortransferfunctionisthesmall-signaltransfer
functionofV
OUT
/V
E/A
.ThisfunctionisdominatedbyaDC
Gainandtheoutputfilter(L
O
andC
O
),withadoublepole
breakfrequencyatF
LC
andazeroatF
ESR
.TheDCGainof
themodulatorissimplytheinputvoltage(V
IN
)dividedbythe
peak-to-peakoscillatorvoltage?V
OSC
.
ModulatorBreakFrequencyEquations
Thecompensationnetworkconsistsoftheerroramplifier
(internaltotheHIP6004)andtheimpedancenetworksZ
IN
andZ
FB
.Thegoalofthecompensationnetworkistoprovide
aclosedlooptransferfunctionwiththehighest0dBcrossing
frequency(f
0dB
)andadequatephasemargin.Phasemargin
isthedifferencebetweentheclosedloopphaseatf
0dB
and
180degrees.Theequationsbelowrelatethecompensation
network’spoles,zerosandgaintothecomponents(R1,R2,
R3,C1,C2,andC3)inFigure8.Usetheseguidelinesfor
locatingthepolesandzerosofthecompensationnetwork:
1.PickGain(R2/R1)fordesiredconverterbandwidth
2.Place1
ST
ZeroBelowFilter’sDoublePole(~75%F
LC
)
3.Place2
ND
ZeroatFilter’sDoublePole
4.Place1
ST
PoleattheESRZero
5.Place2
ND
PoleatHalftheSwitchingFrequency
6.CheckGainagainstErrorAmplifier’sOpen-LoopGain
7.EstimatePhaseMargin-RepeatifNecessary
CompensationBreakFrequencyEquations
Figure9showsanasymptoticplotoftheDC-DCconverter’s
gainvs.frequency.TheactualModulatorGainhasahighgain
peakduetothehighQfactoroftheoutputfilterandisnot
showninFigure9.Usingtheaboveguidelinesshouldgivea
CompensationGainsimilartothecurveplotted.Theopen
looperroramplifiergainboundsthecompensationgain.
CheckthecompensationgainatF
P2
withthecapabilitiesof
theerroramplifier.TheClosedLoopGainisconstructedon
thelog-loggraphofFigure9byaddingtheModulatorGain(in
dB)totheCompensationGain(indB).Thisisequivalentto
multiplyingthemodulatortransferfunctiontothe
compensationtransferfunctionandplottingthegain.
Thecompensationgainusesexternalimpedancenetworks
Z
FB
andZ
IN
toprovideastable,highbandwidth(BW)overall
loop.Astablecontrolloophasagaincrossingwith
-20dB/decadeslopeandaphasemargingreaterthan45
degrees.Includeworstcasecomponentvariationswhen
determiningphasemargin.
ComponentSelectionGuidelines
OutputCapacitorSelection
Anoutputcapacitorisrequiredtofiltertheoutputandsupply
theloadtransientcurrent.Thefilteringrequirementsarea
functionoftheswitchingfrequencyandtheripplecurrent.
Theloadtransientrequirementsareafunctionoftheslew
rate(di/dt)andthemagnitudeofthetransientloadcurrent.
Theserequirementsaregenerallymetwithamixof
capacitorsandcarefullayout.
Modernmicroprocessorsproducetransientloadratesabove
1A/ns.Highfrequencycapacitorsinitiallysupplythetransient
andslowthecurrentloadrateseenbythebulkcapacitors.
Thebulkfiltercapacitorvaluesaregenerallydeterminedby
theESR(effectiveseriesresistance)andvoltagerating
requirementsratherthanactualcapacitancerequirements.
Highfrequencydecouplingcapacitorsshouldbeplacedas
closetothepowerpinsoftheloadasphysicallypossible.Be
carefulnottoaddinductanceinthecircuitboardwiringthat
couldcanceltheusefulnessoftheselowinductance
components.Consultwiththemanufactureroftheloadon
specificdecouplingrequirements.Forexample,Intel
recommendsthatthehighfrequencydecouplingforthe
PentiumProbecomposedofatleastforty(40)1μFceramic
capacitorsinthe1206surface-mountpackage.
Useonlyspecializedlow-ESRcapacitorsintendedfor
switching-regulatorapplicationsforthebulkcapacitors.The
bulkcapacitor’sESRwilldeterminetheoutputripplevoltage
andtheinitialvoltagedropafterahighslew-ratetransient.An
aluminumelectrolyticcapacitor’sESRvalueisrelatedtothe
casesizewithlowerESRavailableinlargercasesizes.
However,theequivalentseriesinductance(ESL)ofthese
capacitorsincreaseswithcasesizeandcanreducethe
usefulnessofthecapacitortohighslew-ratetransientloading.
Unfortunately,ESLisnotaspecifiedparameter.Workwith
yourcapacitorsupplierandmeasurethecapacitor’s
impedancewithfrequencytoselectasuitablecomponent.In
F
LC
1
2πL
O
C
O
??
---------------------------------------=F
ESR
1
2πESRC
O
??
----------------------------------------=
F
Z1
1
2πR2?C1?
----------------------------------=
F
Z2
2πR1R3+()C3??=
F
P1
1
2πR
2
C1C2?
C1C2+
----------------------
??
??
??
------------------------------------------------------=
F
P2
1
2πR3?C3?
----------------------------------=
100
80
60
40
20
0
-20
-40
-60
F
P1
F
Z2
10M1M100K10K1K10010
OPENLOOP
ERRORAMPGAIN
F
Z1
F
P2
20LOG
F
LC
F
ESR
COMPENSATION
GAIN(dB)
FREQUENCY(Hz)
GAIN
20LOG
(V
IN
/?V
OSC
)
MODULATOR
GAIN
(R
2
/R
1
)
FIGURE9.ASYMPTOTICBODEPLOTOFCONVERTERGAIN
CLOSEDLOOP
GAIN
HIP6004
9
mostcases,multipleelectrolyticcapacitorsofsmallcasesize
performbetterthanasinglelargecasecapacitor.
OutputInductorSelection
Theoutputinductorisselectedtomeettheoutputvoltage
ripplerequirementsandminimizetheconverter’sresponse
timetotheloadtransient.Theinductorvaluedeterminesthe
converter’sripplecurrentandtheripplevoltageisafunction
oftheripplecurrent.Theripplevoltageandcurrentare
approximatedbythefollowingequations:
Increasingthevalueofinductancereducestheripplecurrent
andvoltage.However,thelargeinductancevaluesreduce
theconverter’sresponsetimetoaloadtransient.
Oneoftheparameterslimitingtheconverter’sresponsetoa
loadtransientisthetimerequiredtochangetheinductor
current.Givenasufficientlyfastcontrolloopdesign,the
HIP6004willprovideeither0%or100%dutycyclein
responsetoaloadtransient.Theresponsetimeisthetime
requiredtoslewtheinductorcurrentfromaninitialcurrent
valuetothetransientcurrentlevel.Duringthisintervalthe
differencebetweentheinductorcurrentandthetransient
currentlevelmustbesuppliedbytheoutputcapacitor.
Minimizingtheresponsetimecanminimizetheoutput
capacitancerequired.
Theresponsetimetoatransientisdifferentforthe
applicationofloadandtheremovalofload.Thefollowing
equationsgivetheapproximateresponsetimeintervalfor
applicationandremovalofatransientload:
where:I
TRAN
isthetransientloadcurrentstep,t
RISE
isthe
responsetimetotheapplicationofload,andt
FALL
isthe
responsetimetotheremovalofload.Witha+5Vinput
source,theworstcaseresponsetimecanbeeitheratthe
applicationorremovalofloadanddependentuponthe
DACOUTsetting.Besuretocheckbothoftheseequations
attheminimumandmaximumoutputlevelsfortheworst
caseresponsetime.Witha+12Vinput,andoutputvoltage
levelequaltoDACOUT,t
FALL
isthelongestresponsetime.
InputCapacitorSelection
Useamixofinputbypasscapacitorstocontrolthevoltage
overshootacrosstheMOSFETs.Usesmallceramic
capacitorsforhighfrequencydecouplingandbulkcapacitors
tosupplythecurrentneededeachtimeQ1turnson.Placethe
smallceramiccapacitorsphysicallyclosetotheMOSFETs
andbetweenthedrainofQ1andthesourceofQ2.
Theimportantparametersforthebulkinputcapacitorarethe
voltageratingandtheRMScurrentrating.Forreliable
operation,selectthebulkcapacitorwithvoltageandcurrent
ratingsabovethemaximuminputvoltageandlargestRMS
currentrequiredbythecircuit.Thecapacitorvoltagerating
shouldbeatleast1.25timesgreaterthanthemaximum
inputvoltageandavoltageratingof1.5timesisa
conservativeguideline.TheRMScurrentratingrequirement
fortheinputcapacitorofabuckregulatorisapproximately
1/2theDCloadcurrent.
Forathroughholedesign,severalelectrolyticcapacitors
(PanasonicHFQseriesorNichiconPLseriesorSanyo
MV-GXorequivalent)maybeneeded.Forsurfacemount
designs,solidtantalumcapacitorscanbeused,butcaution
mustbeexercisedwithregardtothecapacitorsurgecurrent
rating.Thesecapacitorsmustbecapableofhandlingthe
surge-currentatpower-up.TheTPSseriesavailablefrom
AVX,andthe593DseriesfromSpraguearebothsurge
currenttested.
MOSFETSelection/Considerations
TheHIP6004requires2N-ChannelpowerMOSFETs.
Theseshouldbeselectedbaseduponr
DS(ON)
,gatesupply
requirements,andthermalmanagementrequirements.
Inhigh-currentapplications,theMOSFETpowerdissipation,
packageselectionandheatsinkarethedominantdesign
factors.Thepowerdissipationincludestwolosscomponents;
conductionlossandswitchingloss.Theconductionlossesare
thelargestcomponentofpowerdissipationforboththeupper
andthelowerMOSFETs.Theselossesaredistributed
betweenthetwoMOSFETsaccordingtodutyfactor(seethe
equationsbelow).OnlytheupperMOSFEThasswitching
losses,sincetheSchottkyrectifierclampstheswitchingnode
beforethesynchronousrectifierturnson.Theseequations
assumelinearvoltage-currenttransitionsanddonot
adequatelymodelpowerlossduethereverse-recoveryofthe
lowerMOSFETsbodydiode.Thegate-chargelossesare
dissipatedbytheHIP6004anddon''theattheMOSFETs.
However,largegate-chargeincreasestheswitchinginterval,
t
SW
whichincreasestheupperMOSFETswitchinglosses.
EnsurethatbothMOSFETsarewithintheirmaximumjunction
temperatureathighambienttemperaturebycalculatingthe
temperatureriseaccordingtopackagethermal-resistance
specifications.Aseparateheatsinkmaybenecessary
dependinguponMOSFETpower,packagetype,ambient
temperatureandairflow.
Standard-gateMOSFETsarenormallyrecommendedfor
usewiththeHIP6004.However,logic-levelgateMOSFETs
canbeusedunderspecialcircumstances.Theinputvoltage,
uppergatedrivelevel,andtheMOSFETsabsolutegate-to-
sourcevoltageratingdeterminewhetherlogic-level
MOSFETsareappropriate.
?I=
V
IN
-V
OUT
FsxL
V
OUT
V
IN
?V
OUT
=?IxESR
?
t
RISE
=
LxI
TRAN
V
IN
-V
OUT
t
FALL
=
LxI
TRAN
V
OUT
P
UPPER
=Io
2
xr
DS(ON)
xD+
1
2
IoxV
IN
xt
SW
xF
S
P
LOWER
=Io
2
xr
DS(ON)
x(1-D)
Where:Disthedutycycle=V
OUT
/V
IN
,
t
SW
istheswitchinginterval,and
F
S
istheswitchingfrequency.
HIP6004
10
Figure10showstheuppergatedrive(BOOTpin)supplied
byabootstrapcircuitfromV
CC
.Thebootcapacitor,C
BOOT
developsafloatingsupplyvoltagereferencedtothePHASE
pin.ThissupplyisrefreshedeachcycletoavoltageofVCC
lessthebootdiodedrop(V
D
)whenthelowerMOSFET,Q2
turnson.Logic-levelMOSFETscanonlybeusedifthe
MOSFETsabsolutegate-to-sourcevoltageratingexceeds
themaximumvoltageappliedtoV
CC
.
Figure11showstheuppergatedrivesuppliedbyadirect
connectiontoV
CC
.Thisoptionshouldonlybeusedin
convertersystemswherethemaininputvoltageis+5V
DC
or
less.Thepeakuppergate-to-sourcevoltageisapproximately
V
CC
lesstheinputsupply.For+5Vmainpowerand+12VDC
forthebias,thegate-to-sourcevoltageofQ1is7V.Alogic-
levelMOSFETisagoodchoiceforQ1andalogic-level
MOSFETcanbeusedforQ2ifitsabsolutegate-to-source
voltageratingexceedsthemaximumvoltageappliedtoV
CC
.
SchottkySelection
RectifierD2isaclampthatcatchesthenegativeinductor
swingduringthedeadtimebetweenturningoffthelower
MOSFETandturningontheupperMOSFET.Thediodemust
beaSchottkytypetopreventthelossyparasiticMOSFET
bodydiodefromconducting.Itisacceptabletoomitthediode
andletthebodydiodeofthelowerMOSFETclampthe
negativeinductorswing,butefficiencywilldroponeortwo
percentasaresult.Thediode''sratedreversebreakdown
voltagemustbegreaterthanthemaximuminputvoltage.
+12V
PGND
HIP6004
GND
LGATE
UGATE
PHASE
BOOT
VCC
+5Vor+12V
NOTE:
NOTE:
V
G-S
≈V
CC
C
BOOT
D
BOOT
Q1
Q2
+
-
FIGURE10.UPPERGATEDRIVE-BOOTSTRAPOPTION
V
G-S
≈V
CC
-V
D
D2
+V
D
-
+12V
PGND
HIP6004
GND
LGATE
UGATE
PHASE
BOOT
V
CC
+5VORLESS
NOTE:
NOTE:
V
G-S
≈V
CC
Q1
Q2
+
-
IGURE11.UPPERGATEDRIVE-DIRECTV
CC
DRIVEOPTION
V
G-S
≈V
CC
-5V
D2
HIP6004
11
HIP6004DC-DCConverterApplicationCircuit
Figure12showsanapplicationcircuitofaDC-DCConverter
foranIntelPentiumPromicroprocessor.Detailed
informationonthecircuit,includingacompleteBill-of-
Materialsandcircuitboarddescription,canbefoundin
ApplicationNoteAN9672.IntersilAnswerFAX(321-724-
7800)doc.#99672.
+12V
+V
O
PGND
HIP6004
VSEN
RT
FB
COMP
VID0
VID1
VID2
VID3
OVP
SSPGOOD
D/A
GND
MONITOR
OSC
VCC
L1-1μH
C1
L2
C
O
0.1μF
2x1μF
0.1μF
0.1μF
2.2nF
8.2nF
20K
1.33K
3μH
5x1000μF
9x1000μF
0.1μF
LGATE
UGATE
OCSET
PHASE
BOOT
15
D1
Q1
Q2
2N6394
1K
1000pF
D2
F1
2K
V
IN
=
+5V
OR
+12V
1
2
3
4
5
6
7
9
10
11
12
13
14
15
16
17
19
20
18
AND
PROTECTION
+
-
+
-
ComponentSelectionNotes;
C
0
-9Each1000μF6.3WVDC,SanyoMV-GXorEquivalent
C1-5Each330μF25WVDC,SanyoMV-GXorEquivalent
L2-Core:MicrometalsT50-52B;EachWinding:10Turnsof16AWG
L1-Core:MicrometalsT50-52;Winding:5Turnsof18AWG
D1-1N4148orEquivalent
D2-3A,40VSchottky,MotorolaMBR340orEquivalent
Q1,Q2-IntersilMOSFET;RFP70N03
FIGURE12.PENTIUMPRODC-DCCONVERTER
8
VID4
HIP6004
12
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outnotice.Accordingly,thereaderiscautionedtoverifythatdatasheetsarecurrentbeforeplacingorders.InformationfurnishedbyIntersilisbelievedtobeaccurateand
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HIP6004
SmallOutlinePlasticPackages(SOIC)
NOTES:
1.Symbolsaredefinedinthe“MOSeriesSymbolList”inSection2.2of
PublicationNumber95.
2.DimensioningandtolerancingperANSIY14.5M-1982.
3.Dimension“D”doesnotincludemoldflash,protrusionsorgateburrs.
Moldflash,protrusionandgateburrsshallnotexceed0.15mm(0.006
inch)perside.
4.Dimension“E”doesnotincludeinterleadflashorprotrusions.Interlead
flashandprotrusionsshallnotexceed0.25mm(0.010inch)perside.
5.Thechamferonthebodyisoptional.Ifitisnotpresent,avisualindex
featuremustbelocatedwithinthecrosshatchedarea.
6.“L”isthelengthofterminalforsolderingtoasubstrate.
7.“N”isthenumberofterminalpositions.
8.Terminalnumbersareshownforreferenceonly.
9.Theleadwidth“B”,asmeasured0.36mm(0.014inch)orgreater
abovetheseatingplane,shallnotexceedamaximumvalueof
0.61mm(0.024inch)
10.Controllingdimension:MILLIMETER.Convertedinchdimensions
arenotnecessarilyexact.
INDEX
AREA
E
D
N
123
-B-
0.25(0.010)CAMBS
e
-A-
L
B
M
-C-
A1
A
SEATINGPLANE
0.10(0.004)
hx45
o
C
H
0.25(0.010)BMM
α
M20.3(JEDECMS-013-ACISSUEC)
20LEADWIDEBODYSMALLOUTLINEPLASTICPACKAGE
SYMBOL
INCHESMILLIMETERS
NOTESMINMAXMINMAX
A0.09260.10432.352.65-
A10.00400.01180.100.30-
B0.0130.02000.330.519
C0.00910.01250.230.32-
D0.49610.511812.6013.003
E0.29140.29927.407.604
e0.050BSC1.27BSC-
H0.3940.41910.0010.65-
h0.0100.0290.250.755
L0.0160.0500.401.276
N20207
α0
o
8
o
0
o
8
o
-
Rev.012/93
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