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应用程序
VIN
ctrl
软件
OVP
led指示灯
D1
fb
地
1.8 v 至 6 v
c
入点
4.7
f
启用/pwm 亮度
控制 100 赫兹 至 50 khz
L1
4.7
h
100 nf
右
s
13
c
o
VIN
右
s
25 v
8
5
1
2
3
7
6
4
TPS61043
SLVS465A–DECEMBER2003–REVISEDDECEMBER2003
CONSTANTCURRENTLEDDRIVER
•
currentsourcewith18vovervoltageprotec-
TheTPS61043isahighfrequencyboostconverter
操作
withconstantcurrentoutputthatdriveswhiteLEDsor
•
PowersUpto4LEDsinSeries
类似.theledcurrentissetwiththeexternal
senseresistor(右
s
)andisdirectlyregulatedbythe
•
inputvoltagerange..1.8vto6.0v
feedbackpin(fb)thatregulatesthevoltageacross
•
Internal30VSwitch
thesenseresistorR
s
to252mv(典型值).tocontrolled
•
Upto85%Efficiency
亮度,theledcurrentcanbepulsedbyapply-
•
PreciseBrightnessControlUsingPWMSignal
ingapwm(pulsewidthmodulated)signalwitha
orAnalogSignal
frequencyrangeof100Hzto50kHztothecontrol
管脚(ctrl).toallowhigherflexibility,thedevicecan
•
switchingfrequency..upto1mhz
beconfiguredwherethebrightnesscanbecontrolled
•
internalpowermosfetswitch..400ma
byananalogsignalaswell,asdescribedinthe
•
OperatesWithSmallOutputCapacitorsDown
applicationinformation
截面.toavoidpossible
to100nF
leakagecurrentsthroughtheledsduringshutdown,
•
DisconnectsLEDsDuringShutdown
thecontrolpin(ctrl)disablesthedeviceand
•
noloadquiescentcurrent..38µatyp
disconnectstheledsfromground.formaximum
safetyduringoperation,theoutputhasintegrated
•
shutdowncurrent..0.1µatyp
overvoltageprotectionthatpreventsdamagetothe
•
AvailableinaSmall3mm
×
3mmQFN
devicebylimitingtheoutputvoltagetotypically18V
包装
incaseofahighimpedanceoutput(e?.g.faultyled).
thetps61042deviceprovidesasolutionforappli-
cationswherehigherLEDcurrentsormorethanfour
•
WhiteLEDSupplyforDisplay
ledsinseriesneedtobepowered.
背光/sidelightin
–pda,pocketpc,smartphones
–HandheldDevices
–CellularPhones
一个.outputcapacitorvalueslike1µfandlarger,reducetheledripplecurrentandimprovelineregulation.
figure1.typicalapplication
pleasebeawarethatanimportantnoticeconcerningavailability,标准保修,anduseincriticalapplicationsoftexas
instrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet.
productiondatainformationiscurrentasofpublicationdate.
copyright©2003,texasinstrumentsincorporated
ProductsconformtospecificationsperthetermsoftheTexas
instrumentsstandardwarranty.productionprocessingdoesnot
必要包括测试所有参数.
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