AXP288-SCH-Design-Guide

AXP288AXP288AXP288AXP288SCHSCHSCHSCHDesignDesignDesignDesignGuideGuideGuideGuide1111BUCKBUCKBUCKBUCK1.1Theinductorvalueshouldbe1.0uH,thesaturationcurrentshouldbe1.5timesormorethanthemaximumcurrent,anddcresistanceshouldbelesserthan100mΩ.1.2Theinputcapacitorsvalueshouldbemorethan10uF.1.3Theoutputcapacitorsvalueshouldbemorethan10uF,andlargercapacitorscanbeusedtoreduceoutputripple.1.4WhenBUCK4SETconnectingtoGND,outputvoltageofBUCK4is1.5Vdefault;WhenBUCK4SETfloating,outputvoltageofBUCK4is1.24Vdefault;WhenBUCK4SETconnectingtoVINT,outputvoltageofBUCK4is1.36Vdefault.2222ChargerChargerChargerCharger2.1Theinductorvalueshouldbe1.0uH,thesaturationcurrentshouldbe1.5timesormorethanthemaximumcurrent,anddcresistanceshouldbelesserthan100mΩ.2.2Theinputcapacitorvalueshouldbemorethan10uF.2.3Theoutputcapacitorvalueshouldbemorethan10uF.2.4Thevalueofsamplingresistanceforbatterycurrentshouldbe10mΩand1%accuracy,andthepackageshouldbemorethan0805.2.5Two10uFcapacitorsshouldbeconnectedtothepadsofsamplingresistancerespectively,anda1uFcapacitorshouldbeconnectedinparallelwiththesamplingresistance.2.6TSpinshouldbeconnectedtoNTCthermistorifneedingbatterytemperaturedetection;ifnot,TSpinshouldbeconnectedtoa10Kresistance,orleftitfloatinganddisablethetemperaturedetectionfunctionthroughsoftware.2.7CHGLEDpincanbeusedfortheLEDofchargerstateindication;ifnoneedthisfunction,leftitfloating.NotethatCHGLEDisanopendrainstructureandneedstopulluptootherpower.3333LDOLDOLDOLDO3.1TheoutputcapacitorofVCC_RTCshouldbe10uF.3.2ALDOINshouldconnecttoPS,inputcapacitorvalueshouldbemorethan4.7uF,andvalueofoutputcapacitorsofALDO1/2/3shouldbe4.7~10uF.3.3DLDOINcanconnecttoPSorVBAT-EXT,inputcapacitorvalueshouldbemorethan4.7uF,andvalueoftheoutputcapacitorsofDLDO1/2/3/4shouldbe4.7~10uF.3.4ELDOIN/FLDOINcanconnecttoPS,VBAT-EXTorBUCKoutput,inputcapacitorvalueshouldbemorethan4.7uF,andvalueoftheoutputcapacitorsofELDO1/2/3,FLDO1/2/3shouldbe4.7~10uF.4444IPSIPSIPSIPS4.1ThevalueofinputcapacitorofVBUS1/VBUS2shouldbemorethan4.7uF,andthewithstandvoltageshouldbemorethan16V.4.2ThevalueofoutputcapacitorofPSshouldbemorethan10uF,andthewithstandvoltageshouldbemorethan10V.4.3ThePMOSconnectingBAT-EXTtoPSshouldsatisfythatVth1.5Vandresistanceislessthan30mΩwhenVgs=4.5V.4.43GmoduleandtheloadneedinglargercurrentcanbepoweredbyVBAT-EXT.4.5Fortheapplicationwithnobattery,IPSandChargershouldbemodifiedasbelow:(1)deletetheinductor,samplingresistanceandcorrespondingfiltercapacitors,andinputcapacitorofcharger.(2)deletethePMOSofIPS.(3)addadiodeconnectingPStoBATSENSE.(4)connectBATSENSEtoLOADSENSE.(5)VIN_CHGshouldconnecttoPS.Asthefigureshownbelow:5555OthersOthersOthersOthers5.1PWRONpincanbeusedtopoweronandpowerofftoaddakeyinthispin.5.2CORWPWROKpincanbeusedtoresettoaddakeyinthispin.5.3RSMRST_Bshouldbepulledup,anditisrecommendedtopulluptoALDO3.5.4IRQshouldbepulledup,anditisrecommendedtopulluptoVCC_RTC.