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ID:38666207
大小:161.25 KB
页数:20页
时间:2019-06-17
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1、元器件交易网www.cecb2b.comINTEGRATEDCIRCUITSPCA95318-bitI2CLEDdimmerProductdata2003Nov10PhilipsSemiconductors元器件交易网www.cecb2b.comPhilipsSemiconductorsProductdata8-bitI2CLEDdimmerPCA9531DESCRIPTIONThePCA9531isan8-bitI2C&SMBusI/OexpanderoptimizedfordimmingLEDsin256discretestepsforRed/Green/B
2、lue(RGB)colormixingandbacklightapplications.ThePCA9531containsaninternaloscillatorwithtwouserprogrammableblinkratesanddutycyclescoupledtotheoutputPWM.TheLEDbrightnessiscontrolledbysettingtheblinkratehighenough(>100Hz)thattheblinkingcannotbeseenandthenusingthedutycycletovarytheamounto
3、ftimetheLEDisonandthustheFEATURESaveragecurrentthroughtheLED.•EightLEDdrivers(on,off,flashingataprogrammablerate)Theinitialsetupsequenceprogramsthetwoblinkrates/dutycyclesforeachindividualPWM.Fromthenon,onlyonecommandfromthe•Twoselectable,fullyprogrammableblinkrates(frequencyandbusma
4、sterisrequiredtoturnindividualLEDsON,OFF,BLINKdutycycle)between0.625and160Hz(1.6and6.25milliseconds)RATE1orBLINKRATE2.Basedontheprogrammedfrequency•256brightnessstepsanddutycycle,BLINKRATE1andBLINKRATE2willcausetheLEDstoappearatadifferentbrightnessorblinkatperiodsupto1.6•Input/output
5、snotusedasLEDdriverscanbeusedasregularsecond.TheopendrainoutputsdirectlydrivetheLEDswithGPIOsmaximumoutputsinkcurrentof25mAperbitand100mAper•Internaloscillatorrequiresnoexternalcomponentspackage.•I2CinterfacelogiccompatiblewithSMBusToblinkLEDsatperiodsgreaterthan1.6secondthebusmaster
6、(MCU,MPU,DSP,chipset,etc.)mustsendrepeatedcommandsto•Internalpower-onresetturntheLEDonandoffasiscurrentlydonewhenusingnormalI/O•ExpanderslikethePhilipsPCF8574orPCA9554.AnybitsnotusedNoisefilteronSCL/SDAinputsforcontrollingtheLEDscanbeusedforGeneralPurposeParallel•ActivelowresetinputI
7、nput/Output(GPIO)expansionwhichprovidesasimplesolutionwhenadditionalI/OisneededforACPIpowerswitches,sensors,•EightopendrainoutputsdirectlydriveLEDsto25mApush-buttons,alarmmonitoring,fans,etc.•EdgeratecontrolonoutputsTheactivelowhardwareresetpin(RESET)andPowerOnReset•Noglitchonpower-u
8、p(POR)initia
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