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应用程序
VIN
C1+
C1−
C2+
C2−
EN1
EN2
地
PGND
VOUT
D1
D2
D3
ISET
0.47
f
0.47
f
1
f
1
f
vin = 2.7 v
至 6.5 v
TPS60231
SLVS544–OCTOBER2004
WHITELEDCHARGEPUMPCURRENTSOURCE
WITHPWMBRIGHTNESSCONTROL
•
regulatedoutputcurrentwith0.4%
TheTPS60231chargepumpisoptimizedforwhite
匹配
ledsuppliesincolordisplaybacklightapplications.
thedeviceprovidesaconstantcurrentforeachled,
•
Drivesupto3LEDsat25mAEach
whichtheinitialvaluecanbesetbyanexternal
•
LEDBrightnessControlThroughPWM
电阻.thesupplyvoltagerangesfrom2.7vto
ControlSignal
6.5vandisideallysuitedforallapplicationspowered
•
HighEfficiencybyFractionalConversion
byasingleli-ionbatterycellorthreetofournicd,
with1xand1.5xmodes
nimh,oralkalinebatterycells.overaninputvoltage
rangefrom3.1vto6.5v,thedeviceprovidesahigh
•
1MHzSwitchingFrequency
outputcurrentofupto25mAperLEDwithatotalof
•
2.7vto6.5voperatinginputvoltagerange
75ma.highefficiencyisachievedbyutilizinga
•
InternalSoftstartLimitsInrushCurrent
1x/1.5xfractionalconversiontechniqueincombi-
nationwithverylowdropoutcurrentsources.入点
•
LowInputRippleandLowEMI
加法,thecurrentcontrolledchargepumpensures
•
OvercurrentandOvertemperatureProtected
lowinputcurrentrippleandemi.onlytwoexternal
•
UndervoltageLockoutWithHysteresis
1µfandtwo0.47µfcapacitorsarerequiredtobuild
acompletesmallandlowcostpowersupplysolution.
•
超-small3mmx3mmqfnpackage
toreduceboardspacetoaminimum,设备
switchesat1mhzoperatingfrequencyandisavail-
ableinasmall16-pinqfn(rgt)包装.
•
WhiteLEDBacklightforColorDisplaysin
cellularphones,smartphones,pdas,
handheldpcs,digitalcameras,和
摄像机
•
KeypadBacklight
pleasebeawarethatanimportantnoticeconcerningavailability,标准保修,anduseincriticalapplicationsoftexas
instrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet.
productiondatainformationiscurrentasofpublicationdate.
copyright©2004,texasinstrumentsincorporated
ProductsconformtospecificationsperthetermsoftheTexas
instrumentsstandardwarranty.productionprocessingdoesnot
必要包括测试所有参数.
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