www.德州仪器.com
0
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9
10 11 12 13 14 15
Vo1 − 输出 voltage − v
− 输出 电流 − ai
O
Vo3 = 18 v (doubler 模式)
T
一个
= 25
°
C
T
一个
= 85
°
C
T
一个
= −40
°
C
0
0.02
0.04
0.06
0.08
0.10
0.12
9
10 11 12 13 14 15
Vo1 − 输出 voltage − v
− 输出 电流 − ai
O
Vo3 = 28 v (tripler 模式)
T
一个
= 25
°
C
T
一个
= 85
°
C
T
一个
= −40
°
C
DETAILEDDESCRIPTION
MainBoostConverter
VCOMBuffer
enableandpoweronsequencing(en,enr)
TPS65100
TPS65105
SLVS496B–SEPTEMBER2003–REVISEDMARCH2004
typicalcharacteristics(持续)
Vo3MAXIMUMLOADCURRENTVo3MAXIMUMLOADCURRENT
figure13.figure14.
thetps65100/05consistsofamainboostconverteroperatingwithafixedswitchingfrequencyof1.6mhzto
allowforsmallexternalcomponents.theboostconverteroutputvoltagevo1isalsotheinputvoltage,连接
viathepinsup,forthepositiveandnegativechargepumpsandthebiassupplyforthevcombuffer.thelinear
regulatorcontrollerisindependentfromthissystemwithitsownenablepin.thisallowsthelinearregulator
controllertocontinuetooperatewhiletheothersupplyrailsaredisabledorinshutdownduetoafaultcondition
ononeoftheiroutputs.seethefunctionalblockdiagramformoreinformation.
themainboostconverteroperateswithpwmandafixedswitchingfrequencyof1.6mhz.theconverterusesa
uniquefastresponse,voltagemodecontrollerschemewithinputvoltagefeedforward.thisachievesexcellent
lineandloadregulation(0.2%aloadregulationtypical)andallowstheuseofsmallexternalcomponents.toadd
higherflexibilitytotheselectionofexternalcomponentvaluesthedeviceusesexternalloopcompensation.
Althoughtheboostconverterlookslikeanonsynchronousboostconvertertopologyoperatingindiscontinuous
modeatlightload,thetps65100/05maintainscontinuousconductionevenatlightloadcurrents.
ThisisachievedwithauniquearchitectureusinganexternalSchottkydiodeandanintegratedMOSFETin
parallelconnectedbetweenswandsup(seethefunctionalblockdiagram).theintegratedmosfetq2allows
theinductorcurrenttobecomenegativeatlightloadconditions.forthispurpose,asmallintegratedp-频道
MOSFETwithtypically10
Ω
r
DSon
issufficient.whentheinductorcurrentispositive,theexternalschottkydiode
withthelowerforwardvoltageconductsthecurrent.thiscausestheconvertertooperatewithafixedfrequency
incontinuousconductionmodeovertheentireloadcurrentrange.thisavoidstheringingontheswitchpinas
seenwithastandardnonsynchronousboostconverterandallowsasimplercompensationfortheboost
转换器.
vcoministheinputofthevcombuffer.ifthevcombufferisnotrequiredforcertainapplications,itispossible
toshutdownthevcombufferbystaticallyconnectingvcomintoground,reducingtheoverallquiescent
电流.thevcombufferfeaturessoftstartavoidingalargevoltagedropatvo1duringstart-向上.thevcomin
cannotbepulleddynamicallytogroundduringoperation.
thedevicehastwoenablepins.thesepinsshouldbeterminatedandnotleftfloatingtopreventunpredictable
运作.pullingtheenablepin(en)highenablesthedeviceandstartsthepoweronsequencingwiththemain
boostconvertervo1comingupfirstthenthenegativeandpositivechargepumpsandthevcombuffer.ifthe
vcominpinisheldlow,thevcombufferremainsdisabled.thelinearregulatorhasanindependentenablepin
(enr).pullingthispinlowdisablestheregulator,andpullingthispinhighenablesthisregulator.
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