www.德州仪器.com
BSNandBSPCapacitors
VCLAMPCapacitors
internalregulated5-vsupply(av
DD
)
DifferentialInput
SHUTDOWNOPERATION
usinglow-esrcapacitors
TPA3008D2
SLOS435A–MAY2004–REVISEDJULY2004
thefullh-bridgeoutputstagesuseonlynmostransistors.因此,theyrequirebootstrapcapacitorsforthe
highsideofeachoutputtoturnoncorrectly.a220-nfceramiccapacitor,ratedforatleast25v,mustbe
connectedfromeachoutputtoitscorrespondingbootstrapinput.specifically,one220-nfcapacitormustbe
connectedfromxoutptoxbsp,andone220-nfcapacitormustbeconnectedfromxoutntoxbsn.(seethe
applicationcircuitdiagraminfigure16.)
ThebootstrapcapacitorsconnectedbetweentheBSxxpinsandcorrespondingoutputfunctionasafloating
powersupplyforthehigh-siden-channelpowermosfetgatedrivecircuitry.duringeachhigh-sideswitching
循环,thebootstrapcapacitorsholdthegate-至-sourcevoltagehighenoughtokeepthehigh-sidemosfets
turnedon.
toensurethatthemaximumgate-至-sourcevoltageforthenmosoutputtransistorsisnotexceeded,二
internalregulatorsclampthegatevoltage.two1-µfcapacitorsmustbeconnectedfromvclampl(pin25)和
vclampr(pin36)togroundandmustberatedforatleast25v.thevoltagesatthevclampterminalsvary
withV
CC
andmaynotbeusedforpoweringanyothercircuitry.
TheAV
DD
终端(pin29)istheoutputofaninternallygenerated5-vsupply,usedfortheoscillator,
前置放大器,andvolumecontrolcircuitry.itrequiresa1-µfcapacitor,placedclosetothepin,tokeepthe
regulatorstable.
thisregulatedvoltagecanbeusedtocontrolgain0andgain1terminals,butshouldnotbeusedtodrive
externalcircuitry.
thedifferentialinputstageoftheamplifiercancelsanynoisethatappearsonbothinputlinesofthechannel.至
usethetpa3008d2withadifferentialsource,connectthepositiveleadoftheaudiosourcetotheinpinputand
thenegativeleadfromtheaudiosourcetotheinninput.tousethetpa3008d2withasingle-endedsource,交流
groundtheINPorINNinputthroughacapacitorequalinvaluetotheinputcapacitoronINNorINPandapply
theaudiosourcetoeitherinput.inasingle-endedinputapplication,theunusedinputshouldbeacgroundedat
theaudiosourceinsteadofatthedeviceinputforbestnoiseperformance.
thetpa3008d2employsashutdownmodeofoperationdesignedtoreducesupplycurrent(i
CC
)totheabsolute
minimumlevelduringperiodsofnonuseforpowerconservation.theshutdowninputterminalshouldbeheld
高(seespecificationtablefortrippoint)duringnormaloperationwhentheamplifierisinuse.拉
shutdownlowcausestheoutputstomuteandtheamplifiertoenteralow-currentstate.neverleave
shutdownunconnected,becauseamplifieroperationwouldbeunpredictable.
forthebestpower-offpopperformance,placetheamplifierintheshutdownmodepriortoremovingthepower
supplyvoltage.
低-esrcapacitorsarerecommendedthroughoutthisapplicationsection.areal(asopposedtoideal)电容
canbemodeledsimplyasaresistorinserieswithanidealcapacitor.thevoltagedropacrossthisresistor
minimizesthebeneficialeffectsofthecapacitorinthecircuit.thelowertheequivalentvalueofthisresistance,
themoretherealcapacitorbehaveslikeanidealcapacitor.
18
: 点此下载
