www.德州仪器.com
电源-savemode
DeviceEnable
下面-voltagelockout
Autodischarge
低-batterydetectorcircuit(lbiandlbo)
AntiringingSwitch
tps61010,tps61011
tps61012,tps61013
tps61014,tps61015,tps61016
SLVS314D–SEPTEMBER2000–REVISEDJUNE2005
detaileddescription(持续)
thetps61010isdesignedforhighefficiencyoverawideoutputcurrentrange.evenatlightloads,theefficiency
stayshighbecausetheswitchinglossesoftheconverterareminimizedbyeffectivelyreducingtheswitching
频率.thecontrollerentersapowersave-modeifcertainconditionsaremet.inthismode,thecontrolleronly
switchesonthetransistoriftheoutputvoltagetripsbelowasetthresholdvoltage.itrampsuptheoutputvoltage
withoneorseveralpulses,andgoesagainintopowersave-modeoncetheoutputvoltageexceedsaset
thresholdvoltage.
thedeviceisshutdownwhenenissettognd.inthismode,theregulatorstopsswitching,allinternalcontrol
circuitryincludingthelow-batterycomparator,isswitchedoff,andtheloadisdisconnectedfromtheinput(作
describedaboveinthesynchronousrectifiersection).thisalsomeansthattheoutputvoltagemaydropbelow
theinputvoltageduringshutdown.
thedeviceisputintooperationwhenenissethigh.duringstart-upoftheconverter,thedutycycleislimitedin
ordertoavoidhighpeakcurrentsdrawnfromthebattery.thelimitissetinternallybythecurrentlimitcircuitand
isproportionaltothevoltageonthecomp-管脚.
anunder-voltagelockoutfunctionpreventsthedevicefromstartingupifthesupplyvoltageonvbatislower
thanapproximately0.7v.thisunder-voltagelockoutfunctionisimplementedinordertopreventthe
malfunctioningoftheconverter.wheninoperationandthebatteryisbeingdischarged,thedevicewill
automaticallyentertheshutdownmodeifthevoltageonvbatdropsbelowapproximately0.7v.
Theautodischargefunctionisusefulforapplicationswherethesupplyvoltageofa
µ
c,
µ
p,ormemoryhastobe
removedduringshutdowninordertoensureadefinedstateofthesystem.
theautodischargefunctionisenabledwhentheadenissethigh,andisdisabledwhentheadenissetto
地.whentheautodischargefunctionisenabled,theoutputcapacitorwillbedischargedafterthedeviceis
shutdownbysettingentognd.thecapacitorsconnectedtotheoutputaredischargedbyanintegratedswitch
of300
Ω
,hencethedischargetimedependsonthetotaloutputcapacitance.theresidualvoltageonvoutis
lessthan0.4vafterautodischarge.
thelow-batterydetectorcircuitistypicallyusedtosupervisethebatteryvoltageandtogenerateanerrorflag
whenthebatteryvoltagedropsbelowauser-setthresholdvoltage.thefunctionisactiveonlywhenthedeviceis
使能.whenthedeviceisdisabled,thelbo-pinishighimpedance.thelbo-pingoesactivelowwhenthe
voltageonthelbi-pindecreasesbelowthesetthresholdvoltageof500mv
±
15mv,whichisequaltothe
internalreferencevoltage.thebatteryvoltage,atwhichthedetectioncircuitswitches,canbeprogrammedwitha
resistivedividerconnectedtothelbi-管脚.theresistivedividerscalesdownthebatteryvoltagetoavoltagelevel
of500mv,whichisthencomparedtothelbithresholdvoltage.thelbi-pinhasabuilt-inhysteresisof10mv.
seetheapplicationsectionformoredetailsabouttheprogrammingofthelbi-门槛.
ifthelow-batterydetectioncircuitisnotused,thelbi-pinshouldbeconnectedtognd(ortovbat)andthe
lbo-pincanbeleftunconnected.donotletthelbi-pinfloat.
thedeviceintegratesacircuitthatremovestheringingthattypicallyappearsonthesw-nodewhenthe
converterentersthediscontinuouscurrentmode.inthiscase,thecurrentthroughtheinductorrampstozeroand
theintegratedpmosswitchturnsofftopreventareversecurrentfromtheoutputcapacitorsbacktothebattery.
duetoremainingenergythatisstoredinparasiticcomponentsofthesemiconductorsandtheinductor,aringing
ontheswpinisinduced.theintegratedantiringingswitchclampsthisvoltageinternallytov
BAT
andtherefore,
dampensthisringing.
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