www.德州仪器.com
APPLICATIONINFORMATION
TPS71533
在 输出
V
在
V
输出
C1
0.1
µ
F
0.47
µ
F
地
ExternalCapacitorRequirements
PowerDissipationandJunctionTemperature
P
d(最大值)
T
J
最大值
T
一个
R
JA
(1)
P
D
V
在
V
输出
I
输出
(2)
RegulatorProtection
TPS715xx
SLVS338K–MAY2001–REVISEDSEPTEMBER2005
thetps715xxfamilyofldoregulatorshasbeenoptimizedforultra-lowpowerapplicationssuchasthe
msp430microcontroller.itsultra-lowsupplycurrentmaximizesefficiencyatlightloads,anditshighinputvoltage
rangemakesitsuitableforsuppliessuchasunconditionedsolarpanels.
figure13.typicalapplicationcircuit(fixedvoltageversion)
althoughnotrequired,a0.047-µforlargerinputbypasscapacitor,connectedbetweeninandgndandlocated
closetothedevice,isrecommendedtoimprovetransientresponseandnoiserejectionofthepowersupplyasa
全部的.ahigher-valueinputcapacitormaybenecessaryiflarge,快-上升-timeloadtransientsareanticipatedand
thedeviceislocatedseveralinchesfromthepowersource.
TheTPS715xxrequiresanoutputcapacitorconnectedbetweenOUTandGNDtostabilizetheinternalcontrol
循环.anycapacitor(includingceramicandtantalum)
≥
0.47µfproperlystabilizesthisloop.x7rtypecapacitors
arerecommendedbutx5randothersmaybeused.
toensurereliableoperation,worst-casejunctiontemperatureshouldnotexceed125°c.thisrestrictionlimitsthe
powerdissipationtheregulatorcanhandleinanygivenapplication.toensurethejunctiontemperatureiswithin
acceptablelimits,calculatethemaximumallowabledissipation,p
d(最大值)
,andtheactualdissipation,p
D
,这个
mustbelessthanorequaltoP
d(最大值)
.
themaximum-电源-dissipationlimitisdeterminedusingthefollowingequation:
在哪里:
•
T
J
maxisthemaximumallowablejunctiontemperature.
•
R
θ
JA
isthethermalresistancejunction-至-ambientforthepackage(seethedissipationratingstable).
•
T
一个
istheambienttemperature.
theregulatordissipationiscalculatedusing:
forahigherpowerpackageversionofthetps715xx,seetheTPS715Axx.
thetps715xxpmos-passtransistorhasabuilt-inbackdiodethatconductsreversecurrentwhentheinput
voltagedropsbelowtheoutputvoltage(e.g.,duringpowerdown).currentisconductedfromtheoutputtothe
inputandisnotinternallylimited.ifextendedreversevoltageoperationisanticipated,externallimitingmightbe
适合的.
thetps715xxfeaturesinternalcurrentlimiting.duringnormaloperation,thetps715xxlimitsoutputcurrentto
approximately500ma.whencurrentlimitingengages,theoutputvoltagescalesbacklinearlyuntilthe
overcurrentconditionends.takecarenottoexceedthepowerdissipationratingsofthepackage.
7
: 点此下载
