电流www.topit.me

BRCL4054MERev.
FApr.
-2020DATASHEEThttp://www.
fsbrec.
com1/25BRCL4054ME是一款完整的单节锂离子电池采用恒定电流/恒定电压线性充电器.
其SOT封装与较少的外部元件数目使得BRCL4054ME成为便携式应用的理想选择.
BRCL4054ME可以适合USB电源和适配器电源工作.
TheBRCL4054MEisacompleteconstant-current/constantvoltagelinearchargerforsinglecelllithium-ionbatteries.
ItsThinSOTpackageandlowexternalcomponentcountmaketheBRCL4054MEideallysuitedforportableapplications.
Furthermore,theBRCL4054MEisspecificallydesignedtoworkwithinUSBpowerspecifications.
由于采用了内部PMOSFET架构,加上防倒充电路,所以不需要外部检测电阻器和隔离二极管.
热反馈可对充电电流进行调节,以便在大功率操作或高环境温度条件下对芯片温度加以限制.
充电电压固定于4.
2V,而充电电流可通过一个电阻器进行外部设置当充电电流在达到最终浮充电压之后降至设定值1/10时,BRCL4054ME将自动终止充电循环.
Noexternalsenseresistorisneeded,andnoblockingdiodeisrequiredduetotheinternalMOSFETarchitecture.
Thermalfeedbackregulatesthechargecurrenttolimitthedietemperatureduringhighpoweroperationorhighambienttemperature.
Thechargevoltageisfixedat4.
2V,andthechargecurrentcanbeprogrammedexternallywithasingleresistor.
TheBRCL4054MEautomaticallyterminatesthechargecyclewhenthechargecurrentdropsto1/10ththeprogrammedvalueafterthefinalfloatvoltageisreached.
当输入电压(交流适配器或USB电源)被拿掉时,BRCL4054ME自动进入一个低电流状态,将电池漏电流降至2uA以下.
也可将BRCL4054ME置于停机模式,以而将供电电流降至25uA.
BRCL4054ME的其他特点包括充电电流监控器、欠压闭锁、自动再充电和一个用于指示充电结束和输入电压接入的状态引脚.
Whentheinputsupply(walladapterorUSBsupply)isremoved,theBRCL4054MEautomaticallyentersalowcurrentstate,droppingthebatterydraincurrenttolessthan2μA.
TheBRCL4054MEcanbeputintoshutdownmode,reducingthesupplycurrentto25μA.
Otherfeaturesincludechargecurrentmonitor,undervoltagelockout,automaticrechargeandastatuspintoindicatechargeterminationandthepresenceofaninputvoltage.
高达800mA的可编程充电电流ProgrammableChargeCurrentUpto800mA无需MOSFET、检测电阻器或隔离二极管NoMOSFET,SenseResistororBlockingDiodeRequired用于单节锂离子电池、采用SOT23-5封装的完整线性充电器CompleteLinearChargerin5-LeadSOT-23PackageforSingleCellLithium-IonBatteries恒定电流/恒定电压操作,并具有热调节功能Constant-Current/Constant-VoltageOperationwithThermalRegulationtoMaximizeChargeRateWithoutRiskofOverheating直接从USB端口给单节锂离子电池充电ChargesSingleCellLi-IonBatteriesDirectlyfromUSBPort4.
2V预设充电电压Preset4.
2VChargeVoltagewith±1%Accuracy用于电池电量检测的充电电流监控器输出ChargeCurrentMonitorOutputforGasGauging自动再充电AutomaticRecharge描述/Descriptions特征/FeaturesBRCL4054MERev.
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-2020DATASHEEThttp://www.
fsbrec.
com2/25充电状态输出引脚ChargeStatusOutputPinC/10充电终止C/10ChargeTermination待机模式下的供电电流为25μA25μASupplyCurrentinShutdown2.
9V涓流充电器件版本2.
9VTrickleChargeThreshold软启动限制了浪涌电流Soft-StartLimitsInrushCurrent单灯使用时,充满后灯正在消失.
Whenusingasinglelamp,thelightisfadingafterfullycharging.
蜂窝电话、PDA、MP3播放器;CellularTelephones,PDAs,MP3Players充电座ChargingDocksandCradles蓝牙应用BluetoothApplications.
特征/Features用途/ApplicationsBRCL4054MERev.
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-2020DATASHEEThttp://www.
fsbrec.
com3/25CHRG(引脚1):漏极开路充电状态输出.
在电池的充电过程中,由一个内部N沟道MOSFET将CHRG引脚拉至低电平.
当充电循环结束时,一个约20uA的弱下拉电流源被连接至CHRG引脚,指示一个AC存在状态.
当BRCL4054ME检测到一个欠压闭锁条件时,CHRG引脚被强制为高阻抗状态.
CHRG(Pin1):Open-DrainChargeStatusOutput.
Whenthebatteryischarging,theCHRGpinispulledlowbyaninternalN-channelMOSFET.
Whenthechargecycleiscompleted,aweakpull-downofapproximately20μAisconnectedtotheCHRGpin,indicatingan"ACpresent"condition.
WhentheBRCL4054MEdetectsanundervoltagelockoutcondition,CHRGisforcedhighimpedance.
GND(引脚2):地.
GND(Pin2):Ground.
BAT(引脚3):充电电流输出.
该引脚向电池提供充电电流并将最终浮充电压调节至4.
2V该引脚的一个精准内部电阻分压器设定浮充电压,在停机模式中,该内部电阻分压器断开.
BAT(Pin3):ChargeCurrentOutput.
Provideschargecurrenttothebatteryandregulatesthefinalfloatvoltageto4.
2V.
Aninternalprecisionresistordividerfromthispinsetsthefloatvoltagewhichisdisconnectedinshutdownmode.
VCC(引脚4):正的输入电源电压.
该引脚向充电器供电.
VCC的变化范围在4.
25V-6.
5V之间,并应通过至少一个1uF电容器进行旁路.
当VCC降至BAT引脚电压的30mV以内,BRCL4054ME进入停机模式,从而IBAT降至2uA以下.
VCC(Pin4):PositiveInputSupplyVoltage.
Providespowertothecharger.
VCCcanrangefrom4.
25Vto6.
5Vandshouldbebypassedwithatleasta1μFcapacitor.
WhenVCCdropstowithin30mVoftheBATpinvoltage,theBRCL4054MEentersshutdownmode,droppingIBATtolessthan2μA.
内部等效电路/应用电路EquivalentCircuitorApplicationCircuit引脚排列/Pinning13245BRCL4054MERev.
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com4/25PROG(引脚5):充电电流设定,充电电流监控和停机引脚.
在该引脚与地之间连接一个精度为1%的电阻器PPRGO可以设定充电电流.
当在恒定电流模式下进行充电时,该引脚的电压被维持在1V在所有的模式中都可以利用该引脚上的电压来测算充电电流,公式为IBAT=(VPROG/RPROG)*1000.
PROG引脚还可以用来关断充电器.
将设定电阻器与地短接,内部一个3.
0uA电流将PROG引脚拉至高电平.
当该引脚的电压达到1.
21V的停机门限电压时,充电器进入停机模式,充电停止且输入电源电流降至25uA.
该引脚还夹约2.
4V,电流1.
5mA,重新将RPROG与地相连将使充电器恢复正常操作状态.
PROG(Pin5):ChargeCurrentProgram,ChargeCurrentMonitorandShutdownPin.
Thechargecurrentisprogrammedbyconnectinga1%resistor,RPROG,toground.
Whencharginginconstant-currentmode,thispinservosto1V.
Inallmodes,thevoltageonthispincanbeusedtomeasurethechargecurrentusingthefollowingformula:IBAT=(VPROG/RPROG)*1000.
ThePROGpincanalsobeusedtoshutdownthecharger.
Disconnectingtheprogramresistorfromgroundallowsa3μAcurrenttopullthePROGpinhigh.
Whenitreachesthe1.
21Vshutdownthresholdvoltage,thechargerentersshutdownmode,chargingstopsandtheinputsupplycurrentdropsto25μA.
Thispinisalsoclampedtoapproximately2.
4V.
Drivingthispintovoltagesbeyondtheclampvoltagewilldrawcurrentsashighas1.
5mA.
ReconnectingRPROGtogroundwillreturnthechargertonormaloperation.
印章代码/Marking见印章说明.
SeeMarkingInstructions引脚排列/PinningBRCL4054MERev.
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-2020DATASHEEThttp://www.
fsbrec.
com5/25参数Parameter数值Rating单位UnitInputSupplyVoltage(VCC)-0.
3to10VPROG-0.
3toVCC+0.
3VBAT-0.
3to7VCHRG-0.
3to10VBATShort-CircuitDurationContinuousBATPinCurrent800mAPROGPinCurrent800μAMaximumJunctionTemperature125℃OperatingAmbientTemperatureRange(Note2)-40~85℃StorageTemperatureRange-65~125℃LeadTemperature(Soldering,10sec)300℃参数Parameter符号Symbol测试条件TestConditions最小值Min典型值Typ最大值Max单位UnitInputSupplyVoltageVCC4.
256.
5VInputSupplyCurrentICCChargeMode(Note3),RPROG=10k3002000μAStandbyMode(ChargeTerminated)200500μAShutdownMode(RPROGNotConnectedVCC1584.
204.
242VBATPinCurrentIBATRPROG=10kCurrentMode93100107mARPROG=2kCurrentMode465500535mAStandbyModeVBAT=4.
2V0-2.
5-6.
0μAShutdownMode(RPROGNotConnected)±1.
0±2.
0μASleepModeVCC=0V±1.
0±2.
0μATrickleChargeCurrentITRIKLVBAT82.
93.
0VTrickleChargeHysteresisVoltageVTRHYSRPROG=10k6080110mV极限参数/AbsoluteMaximumRatings(Ta=25℃)(Note1)电性能参数/ElectricalCharacteristics(Ta=25℃,VCC=5V)BRCL4054MERev.
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-2020DATASHEEThttp://www.
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com6/25参数Parameter符号Symbol测试条件TestConditions最小值Min典型值Typ最大值Max单位UnitVCCUndervoltageLockoutThresholdVUVFromVCCLowtoHigh3.
73.
83.
92VVCCUndervoltageLockoutHysteresisVUVHYS150200300mVManualShutdownThresholdVoltageVMSDPROGPinRising1.
151.
211.
30VPROGPinFalling0.
91.
01.
1VVCC–VBATLockoutThresholdVoltageVASDVCCfromLowtoHigh70100140mVVCCfromHightoLow5.
03050mVC/10TerminationCurrentThresholdITERMRPROG=10k(Note4)0.
0850.
100.
115mA/mARPROG=2k0.
0850.
100.
115mA/mAPROGPinVoltageVPROGRPROG=10kCurrentMode0.
931.
01.
07VCHRGPinWeakPull-DownCurrentICHRGVCHRG=5V8.
02035μACHRGPinOutputLowVoltageVCHRGICHRG=5mA0.
350.
60VRechargeBatteryThresholdVoltageVRECHRGVFLOAT-VRECHRG100150200mVJunctionTemperatureinConstantTemperatureModeTLIM120℃PowerFET"ON"Resistance(BetweenVCCandBAT)RON600mSoft-StartTimetSSIBAT=0toIBAT=1000V/RPROG100μsRechargeComparatorFilterTimetRECHARGEVBATHightoLow0.
752.
04.
5msTerminationComparatorFilterTimetTERMIBATFallingBelowICHG/1040010002500μsPROGPinPull-UpCurrentIPROG3.
0μANotes:Note1:AbsoluteMaximumRatingsarethosevaluesbeyondwhichthelifeofthedevicemaybeimpaired.
Note2:TheBRCL4054ME-4.
2isguaranteedtomeetperformancespecificationsfrom0°Cto70°C.
Specificationsoverthe–40°Cto85°Coperatingtemperaturerangeareassuredbydesign,characterizationandcorrelationwithstatisticalprocesscontrols.
Note3:SupplycurrentincludesPROGpincurrent(approximately100μA)butdoesnotincludeanycurrentdeliveredtothebatterythroughtheBATpin(approximately100mA).
Note4:ITERMisexpressedasafractionofmeasuredfullchargecurrentwithindicatedPROGresistor.
电性能参数/ElectricalCharacteristics(Ta=25℃)BRCL4054MERev.
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com7/25原理框图/FunctionalBlockDiagramBRCL4054MERev.
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com9/25电参数曲线图/ElectricalCharacteristicCurveBRCL4054MERev.
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-2020DATASHEEThttp://www.
fsbrec.
com10/25工作原理/OPERATIOUBRCL4054ME是一款采用恒定电流/恒定电压算法的单节锂离子电池充电器.
它能够提供800mA的充电电流(借助一个热设计良好的PCB布局)和一个内部P沟道功率MOSFET和热调节电路.
无需隔离二极管或外部电流检测电阻器;因此,基本充电器电路仅需要两个外部元件.
不仅如此,BRCL4054ME还能够从一个USB电源获得工作电源.
TheBRCL4054MEisasinglecelllithium-ionbatterychargerusingaconstant-current/constant–voltagealgorithm.
Itcandeliverupto800mAofchargecurrent(usingagoodthermalPCBlayout)withafinalfloatvoltageaccuracyof±1%.
TheBRCL4054MEincludesaninternalP-channelpowerMOSFETandthermalregulationcircuitry.
Noblockingdiodeorexternalcurrentsenseresistorisrequired;thus,thebasicchargercircuitrequiresonlytwoexternalcomponents.
Furthermore,theBRCL4054MEiscapableofoperatingfromaUSBpowersource.
正常充电循环/NormalChargeCycle当Vcc引脚电压升至UVLO门限电平以上且在PROG引脚与地之间连接了一个精度为1%的设定电阻器或当一个电池与充电器输出端相连时,一个充电循环开始.
如果BAT引脚电平低于2.
9V,则充电器进入涓流充电模式.
在该模式中,BRCL4054ME提供约1/10的设定充电电流,以便将电流电压提升至一个安全的电平,从而实现满电流充电.
AchargecyclebeginswhenthevoltageattheVCCpinrisesabovetheUVLOthresholdlevelanda1%programresistorisconnectedfromthePROGpintogroundorwhenabatteryisconnectedtothechargeroutput.
IftheBATpinislessthan2.
9V,thechargerenterstricklechargemode.
Inthismode,theBRCL4054MEsuppliesapproximately1/10theprogrammedchargecurrenttobringthebatteryvoltageuptoasafelevelforfullcurrentcharging.
当BAT引脚电压升至2.
9V以上时,充电器进入恒定电流模式,此时向电池提供恒定的充电电流.
当BAT引脚电压达到最终浮充电压(4.
2V)时,BRCL4054ME进入恒定电压模式,且充电电流开始减小.
当充电电流降至设定值的1/10,充电循环结束.
WhentheBATpinvoltagerisesabove2.
9V,thechargerentersconstant-currentmode,wheretheprogrammedchargecurrentissuppliedtothebattery.
WhentheBATpinapproachesthefinalfloatvoltage(4.
2V),theBRCL4054MEentersconstant-voltagemodeandthechargecurrentbeginstodecrease.
Whenthechargecurrentdropsto1/10oftheprogrammedvalue,thechargecycleends.
充电电流的设定/ProgrammingChargeCurrent充电电流是采用一个连接在PROG引脚与地之间的电阻器来设定的.
电流充电电流是PROG引脚输出电流的1000倍.
设定电阻器和充电电流采用下列公式来计算:ThechargecurrentisprogrammedusingasingleresistorfromthePROGpintoground.
Thebatterychargecurrentis1000timesthecurrentoutofthePROGpin.
Theprogramresistorandthechargecurrentarecalculatedusingthefollowingequations:从BAT引脚输出的充电电流可通过监视PROG引脚电压随时确定,公式如下:ThechargecurrentoutoftheBATpincanbedeterminedatanytimebymonitoringthePROGpinvoltageusingthefollowingequation:BRCL4054MERev.
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-2020DATASHEEThttp://www.
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com11/25充电终止/ChargeTermination当充电电流在达到最终浮充电压之后降至设定值的1/10时,充电循环被终止.
该条件是通过采用一个内部滤波比较器对PROG引脚进行监控来检测的.
当PROG引脚电压降至100mV以下的时间超过tTERM(一般为1.
0ms)时,充电被终止.
充电电流被锁断,BRCL4054ME进入待机模式,此时输入电源电流降至200μA.
(注:C/10终止在涓流充电和热限制模式中失效).
Achargecycleisterminatedwhenthechargecurrentfallsto1/10ththeprogrammedvalueafterthefinalfloatvoltageisreached.
Thisconditionisdetectedbyusinganinternal,filteredcomparatortomonitorthePROGpin.
WhenthePROGpinvoltagefallsbelow100mV1forlongerthantTERMtypically1ms),chargingisterminated.
ThechargecurrentislatchedoffandtheBRCL4054MEentersstandbymode,wheretheinputsupplycurrentdropsto200μA.
(Note:C/10terminationisdisabledintricklechargingandthermallimitingmodes).
充电时,BAT引脚上的瞬变负载会使PROG引脚电压在DC充电电流降至设定值的1/10之间短暂地降至100mV以下.
终止比较器上的1.
0ms滤波时间(tTERM)确保这种性质的瞬变负载不会导致充电循环过早终止.
一旦平均充电电流降至设定值的1/10以下,BRCL4054ME即终止充电循环并停止通过BAT引脚提供任何电流.
在这种状态下,BAT引脚上的所有负载都必须由电池来供电.
Whencharging,transientloadsontheBATpincancausethePROGpintofallbelow100mVforshortperiodsoftimebeforetheDCchargecurrenthasdroppedto1/10ththeprogrammedvalue.
The1msfiltertime(tTERM)ontheterminationcomparatorensuresthattransientloadsofthisnaturedonotresultinprematurechargecycletermination.
Oncetheaveragechargecurrentdropsbelow1/10ththeprogrammedvalue,theBRCL4054MEterminatesthechargecycleandceasestoprovideanycurrentthroughtheBATpin.
Inthisstate,allloadsontheBATpinmustbesuppliedbythebattery.
在待机模式中,BRCL4054ME对BAT引脚电压进行连续监控.
如果该引脚电压降到4.
05V的再充电电门限(VRECHRG)以下,则另一个充电循环开始并再次向电池供应电流.
当在待机模式中进行充电循环的手动再启动时,必须取消然后再施加输入电压,或者必须关断充电器并使用PROG引脚进行再启动.
图1示出了一个典型充电循环的状态图.
TheBRCL4054MEconstantlymonitorstheBATpinvoltageinstandbymode.
Ifthisvoltagedropsbelowthe4.
05Vrechargethreshold(VRECHRG),anotherchargecyclebeginsandcurrentisonceagainsuppliedtothebattery.
Tomanuallyrestartachargecyclewheninstandbymode,theinputvoltagemustberemovedandreapplied,orthechargermustbeshutdownandrestartedusingthePROGpin.
Figure1showsthestatediagramofatypicalchargecycle.
充电状态指示器/ChargeStatusIndicator(CHRG)充电状态输出具有三种不同的状态:强下拉(约10mA)、弱下拉(约20μA)和高阻抗.
强下拉状态表示BRCL4054ME处于一个充电循环中.
一旦充电循环被终止,则引脚状态由欠压闭锁条件来决定.
弱下拉状态表示Vcc满足UVLO条件且BRCL4054ME处于充电就绪状态.
高阻抗状态表示BRCL4054ME处于欠压闭锁模式:要么Vcc高出BAT引脚电压的幅度不足100mV,要么施加在Vcc引脚上的电压不足.
可采用一个微处理器来区分这三种状态--在"应用信息"部分将对此方法进行讨论.
Thechargestatusoutputhasthreedifferentstates:strongpull-down(~10mA),weakpull-down(~20μA)andhighimpedance.
Thestrongpull-downstateindicatesthattheBRCL4054MEisinachargecycle.
Oncethechargecyclehasterminated,thepinstateisdeterminedbyundervoltagelockoutconditions.
Aweakpull-downindicatesthatVCCmeetstheUVLOconditionsandtheBRCL4054MEisreadytocharge.
HighimpedanceindicatesthattheBRCL4054MEisinundervoltagelockoutmode:eitherVCCislessthan100mVabovetheBATpinvoltageorinsufficientvoltageisappliedtotheVCCpin.
Amicroprocessorcanbeusedtodistinguishbetweenthesethreestates—thismethodisdiscussedintheApplicationsInformationsection.
BRCL4054MERev.
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com12/25热限制/ThermalLimiting如果芯片温度试图上升超过120℃的预设值以上,则一个内部热反馈环路将减小设定的充电电流.
该功能可防止BRCL4054ME过热,并允许用户提高给定电路板功率处理能力的上限而没有损坏BRCL4054ME的风险.
在保证充电器将在最坏情况条件下自动减小电流的前提下,可根据典型(而不是最坏情况)环境温度来设定充电电流.
有关ThinSOT功率方面的考虑将在"应用信息"部分做进一步讨论.
Aninternalthermalfeedbackloopreducestheprogrammedchargecurrentifthedietemperatureattemptstoriseaboveapresetvalueofapproximately120℃.
ThisfeatureprotectstheRCL4054MEfromexcessivetemperatureandallowstheusertopushthelimitsofthepowerhandlingcapabilityofagivencircuitboardwithoutriskofdamagingtheBRCL4054ME.
Thechargecurrentcanbesetaccordingtotypical(notworst-case)ambienttemperaturewiththeassurancethatthechargerwillautomaticallyreducethecurrentinworst-caseconditions.
ThinSOTpowerconsiderationsarediscussedfurtherintheApplicationsInformationsection.
欠压闭锁/UndervoltageLockout(UVLO)一个内部欠压闭锁电路对输入电压进行监控,并在Vcc升至欠压闭锁门限以上之前使充电器保持在停机模式.
UVLO电路有一个内置的滞后200Mv.
此外在功率MOSFET的反向电流保护,UVLO电路将使充电器保持在停机模式.
如果UVLO比较器发生跳变,则在Vcc升至比电池电压高100mV之前充电器将不会退出停机模式.
AninternalundervoltagelockoutcircuitmonitorstheinputvoltageandkeepsthechargerinshutdownmodeuntilVCCrisesabovetheundervoltagelockoutthreshold.
TheUVLOcircuithasabuilt-inhysteresisof200mV.
Furthermore,toprotectagainstreversecurrentinthepowerMOSFET,theUVLOcircuitkeepsthechargerinshutdownmodeifVCCfallstowithin30mVofthebatteryvoltage.
IftheUVLOcomparatoristripped,thechargerwillnotcomeoutofshutdownmodeuntilVCCrises100mVabovethebatteryvoltage.
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-2020DATASHEEThttp://www.
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com13/25手动停机/ManualShutdown在充电循环中的任何时刻都能通过去掉RPROG(从而使RPROG引脚浮置)来把BRCL4054ME置于停机模式.
这使得电池漏电流降至2μA以下,且电源电流降至50μA以下.
重新连接设定电阻器可启动一个新的充电循环.
Atanypointinthechargecycle,theBRCL4054MEcanbeputintoshutdownmodebyremovingRPROGthusfloatingthePROGpin.
Thisreducesthebatterydraincurrenttolessthan2μAandthesupplycurrenttolessthan50μA.
Anewchargecyclecanbeinitiatedbyreconnectingtheprogramresistor.
在手动停机模式中,只要Vcc高到足以超过UVLO条件,CHRG引脚都将处于弱下拉状态.
如果BRCL4054ME处于欠压闭锁模式,则CHRG引脚呈高阻抗状态:要么Vcc高出BAT引脚电压的幅度不足100mV,要么施加在Vcc引脚上的电压不足.
Inmanualshutdown,theCHRG————————pinisinaweakpull-downstateaslongasVCCishighenoughtoexceedtheUVLOconditions.
TheCHRG————————pinisinahighimpedancestateiftheBRCL4054MEisinundervoltagelockoutmode:eitherVCCiswithin100mVoftheBATpinvoltageorinsufficientvoltageisappliedtotheVCCpin.
自动再启动/AutomaticRecharge一旦充电循环被终止,BRCL4054ME立即采用一个具有2.
0ms滤波时间(tRECHARGE)的比较器来对BAT引脚上的电压进行连续监控.
当电池电压降至4.
05V(大致对应于电池容量的80%至90%)以下时,充电循环重新开始.
这确保了电池被维持在(或接近)一个满充电状态,并免除了进行周期性充电循环启动的需要.
在再充电循环过程中,CHRG引脚输出进入一个强下拉状态.
Oncethechargecycleisterminated,theBRCL4054MEcontinuouslymonitorsthevoltageontheBATpinusingacomparatorwitha2msfiltertime(tRECHARGE).
Achargecyclerestartswhenthebatteryvoltagefallsbelow4.
05V(whichcorrespondstoapproximately80%to90%batterycapacity).
Thisensuresthatthebatteryiskeptatornearafullychargedconditionandeliminatestheneedforperiodicchargecycleinitiations.
CHRGoutputentersastrongpull-downstateduringrechargecycles.
Figure1.
StateDiagramofaTypicalChargeCycleBRCL4054MERev.
FApr.
-2020DATASHEEThttp://www.
fsbrec.
com14/25稳定性的考虑/StabilityConsiderations只要电池与充电器的输出端相连,恒定电压模式反馈环路就能够在未采用一个外部电容器的情况下保持稳定.
在没有接电池时,为了减小纹波电压,建议采用一个输出电容器.
当采用大数值的低ESR陶瓷电容器时,建议增加一个与电容器串联的1Ω电阻器.
如果使用的是钽电容,则不需要串联电阻器.
Theconstant-voltagemodefeedbackloopisstablewithoutanoutputcapacitorprovidedabatteryisconnectedtothechargeroutput.
Withnobatterypresent,anoutputcapacitorisrecommendedtoreduceripplevoltage.
Whenusinghighvalue,lowESRceramiccapacitors,itisrecommendedtoadda1resistorinserieswiththecapacitor.
Noseriesresistorisneedediftantalumcapacitorsareused.
在恒定电流模式中,位于反馈环路中的是PROG引脚,而不是电池.
恒定电流模式的稳定性受PROG引脚阻抗的影响.
当PROG引脚上没有附加电容会减小设定电阻器的最大容许阻值.
PROG引脚上的极点频率应保持在CPROG,则可采用下式来计算RPROG的最大电阻值:Inconstant-currentmode,thePROGpinisinthefeedbackloop,notthebattery.
Theconstant-currentmodestabilityisaffectedbytheimpedanceatthePROGpin.
WithnoadditionalcapacitanceonthePROGpin,thechargerisstablewithprogramresistorvaluesashighas20k.
However,additionalcapacitanceonthisnodereducesthemaximumallowedprogramresistor.
ThepolefrequencyatthePROGpinshouldbekeptabove100kHz.
Therefore,ifthePROGpinisloadedwithacapacitance,CPROG,thefollowingequationcanbeusedtocalculatethemaximumresistancevalueforRPROG:对用户来说,他们更感兴趣的可能是充电电流,而不是瞬态电流.
例如,如果一个运行在低电流模式的开关电源与电池并联,则从BAT引脚流出的平均电流通常比瞬态电流脉冲更加重要.
在这种场合,电流通常比瞬态电流脉冲更加重要.
在这种场合,可在PROG引脚上采用一个简单的RC滤波器来测量平均的电池电流(如图2所示).
在PROG引脚和滤波电容器之间增设了一个10k电阻器以确保稳定性.
Average,ratherthaninstantaneous,chargecurrentmaybeofinteresttotheuser.
Forexample,ifaswitchingpowersupplyoperatinginlowcurrentmodeisconnectedinparallelwiththebattery,theaveragecurrentbeingpulledoutoftheBATpinistypicallyofmoreinterestthantheinstantaneouscurrentpulses.
Insuchacase,asimpleRCfiltercanbeusedonthePROGpintomeasuretheaveragebatterycurrentasshowninFigure2.
A10kresistorhasbeenaddedbetweenthePROGpinandthefiltercapacitortoensurestability.
Figure2.
IsolatingCapacitiveLoadonPROGPinandFilteringBRCL4054MERev.
FApr.
-2020DATASHEEThttp://www.
fsbrec.
com15/25功率损耗/PowerDissipationBRCL4054ME因热反馈的缘故而减小充电电流的条件可通过IC中的功率损耗来估算.
这种功率损耗几乎全部都是由内部MOSFET产生的――这可由下式近似求出:TheconditionsthatcausetheBRCL4054MEtoreducechargecurrentthroughthermalfeedbackcanbeapproximatedbyconsideringthepowerdissipatedintheIC.
NearlyallofthispowerdissipationisgeneratedbytheinternalMOSFET-thisiscalculatedtobeapproximately:式中的PD为耗散的功率,VCC为输入电源电压,VBAT为电池电压,IBAT为充电电流.
当热反馈开始对IC提供保护时,环境温度近似为:WherePDisthepowerdissipated,VCCistheinputsupplyvoltage,VBATisthebatteryvoltageandIBATisthechargecurrent.
TheapproximateambienttemperatureatwhichthethermalfeedbackbeginstoprotecttheICis:实例:通过编程使一个从5VUSB电源获得工作电源的BRCL4054ME向一个具有3.
75V电压的放电锂离子电池提供400mA满幅度电流.
假设θJA为150℃/W(请参见电路板布局的考虑),当BRCL4054ME开始减小充电电流时,环境温度近似为:Example:AnBRCL4054MEoperatingfroma5VUSBsupplyisprogrammedtosupply400mAfull-scalecurrenttoadischargedLi-Ionbatterywithavoltageof3.
75V.
AssumingθJAis150℃/W(seeBoardLayoutConsiderations),theambienttemperatureatwhichtheBRCL4054MEwillbegintoreducethechargecurrentisapproximately:BRCL4054ME可在45℃以上的环境温度条件下使用,但充电电流将被降至400mA以下.
对于一个给定的环境温度,充电电流可有下式近似求出:TheBRCL4054MEcanbeusedabove45℃ambient,butthechargecurrentwillbereducedfrom400mA.
Theapproximatecurrentatagivenambienttemperaturecanbeapproximatedby:再以60℃的环境温度来考虑前面的例子.
充电电流将被大约减小至:Usingthepreviousexamplewithanambienttemperatureof60℃,thechargecurrentwillbereducedtoapproximately:BRCL4054MERev.
FApr.
-2020DATASHEEThttp://www.
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com16/25功率损耗/PowerDissipation不仅如此,正如工作原理部分所讨论的那样,当热反馈使充电电流减小时,PROG引脚上的电压也将成比例地减小.
Moreover,whenthermalfeedbackreducesthechargecurrent,thevoltageatthePROGpinisalsoreducedproportionallyasdiscussedintheOperationsection.
切记不需要在BRCL4054ME应用设计中考虑最坏的热条件,这一点很重要,因为该IC将在结温达到120℃左右时自动降低功耗.
ItisimportanttorememberthatBRCL4054MEapplicationsdonotneedtobedesignedforworst-casethermalconditionssincetheICwillautomaticallyreducepowerdissipationwhenthejunctiontemperaturereachesapproximately120℃.
热考虑/ThermalConsiderations由于SOT封装的外形尺寸很小,因此,需要采用一个热设计精良的PC板布局以最大幅度地增加可使用的充电电流,这一点非常重要.
用于耗散IC所产生的热量的散热通路从芯片至引线框架,并通过峰值后引线(特别是接地引线)到达PC板铜面.
PC板铜面为散热器.
引脚相连的铜箔面积应尽可能地宽阔,并向外延伸至较大的铜面积,以便将热量散播到周围环境中.
至内部或背部铜电路层的通孔在改善充电器的总体热性能方面也是颇有用处的.
当进行PC板布局设计时,电路板上与充电器无关的其他热源也是必须予以考虑的,因为它们将对总体温升和最大充电电流有所影响.
BecauseofthesmallsizeoftheThinSOTpackage,itisveryimportanttouseagoodthermalPCboardlayouttomaximizetheavailablechargecurrent.
ThethermalpathfortheheatgeneratedbytheICisfromthedietothecopperleadframe,throughthepackageleads,(especiallythegroundlead)tothePCboardcopper.
ThePCboardcopperistheheatsink.
Thefootprintcopperpadsshouldbeaswideaspossibleandexpandouttolargercopperareastospreadanddissipatetheheattothesurroundingambient.
Feedthroughviastoinnerorbacksidecopperlayersarealsousefulinimprovingtheoverallthermalperformanceofthecharger.
Otherheatsourcesontheboard,notrelatedtothecharger,mustalsobeconsideredwhendesigningaPCboardlayoutbecausetheywillaffectoveralltemperatureriseandthemaximumchargecurrent.
下表罗列了几种不同电路板尺寸和铜面积条件下的热阻.
所有的测量结果都是在静止空气中的3/32″FR-4电路板上(器件安装于其顶面)获得的.
Thefollowingtableliststhermalresistanceforseveraldifferentboardsizesandcopperareas.
Allmeasurementsweretakeninstillairon3/32"FR-4boardwiththedevicemountedontopside.
Table1.
实测热阻(双层电路板*)MeasuredThermalResistance(2-LayerBoard*)CopperAreaBoardAreaThermalRrsistanceJunction-to-AmbientTopsideBackside2500mm22500mm22500mm2125℃/W1000mm22500mm22500mm2125℃/W225mm22500mm22500mm2130℃/W100mm22500mm22500mm2135℃/W50mm22500mm22500mm2150℃/W*每层采用1盎司铜箔/EachlayerusesoneouncecopperTable2.
实测热阻(四层电路板*)MeasuredThermalResistance(4-LayerBoard**)CopperArea(EachSide)BoardAreaThermalResistanceJunction-to-Ambient2500mm2***2500mm280℃/W*顶层和底层采用2盎司铜箔,内层采用1盎司铜箔/Topandbottomlayersusetwoouncecopper,innerlayersuseoneouncecopper.
**总铜面积为10000mm2/10,000mm2totalcopperareaBRCL4054MERev.
FApr.
-2020DATASHEEThttp://www.
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com17/25增加热调节电流/IncreasingThermalRegulationCurrent降低内部MOSFET两端的压降能够显著减少IC中的功耗.
在热调节期间,这具有增加输送至电池的电流的作用.
对策之一是通过一个外部元件(例如一个电阻器或二极管)将一部分功率耗散掉.
ReducingthevoltagedropacrosstheinternalMOSFETcansignificantlydecreasethepowerdissipationintheIC.
Thishastheeffectofincreasingthecurrentdeliveredtothebatteryduringthermalregulation.
Onemethodisbydissipatingsomeofthepowerthroughanexternalcomponent,suchasaresistorordiode.
实例:通过编程使一个从5V交流适配器获得工作电源的BRCL4054ME向一个具有3.
75V电压的放电锂离子电池提供800mA的满幅充电电流.
假设θJA为125℃/W,则在25℃的环境温度条件下,充电电流近似为:Example:AnBRCL4054MEoperatingfroma5Vwalladapterisprogrammedtosupply800mAfull-scalecurrenttoadischargedLi-Ionbatterywithavoltageof3.
75V.
AssumingθJAis125℃/W,theapproximatechargecurrentatanambienttemperatureof25℃is:通过降低一个与5V交流适配器串联的电阻器两端的电压(如图3所示),可减少片上功耗,从而增大热调整的充电电流:Bydroppingvoltageacrossaresistorinserieswitha5Vwalladapter(showninFigure3),theon-chippowerdissipationcanbedecreased,thusincreasingthethermallyregulatedchargecurrentFigure3.
ACircuittoMaximizeThermalModeChargeCurrent利用二次方程可求出IBAT2.
SolvingforIBATusingthequadraticformula2.
BRCL4054MERev.
FApr.
-2020DATASHEEThttp://www.
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com18/25增加热调节电流/IncreasingThermalRegulationCurrent取RCC=0.
25Ω、VS=5V、VBAT=3.
75V、TA=25℃且θJA=125℃/W,我们可以计算出热调整的充电电流:IBAT=708.
4mAUsingRCC=0.
25,VS=5V,VBAT=3.
75V,TA=25℃CandθJA=125℃/Wwecancalculatethethermallyregulatedchargecurrenttobe:IBAT=708.
4mA虽然这种应用可以在热调整模式中向电池输送更多的能量并缩短充电时间,但在电压模式中,如果VCC变得足够低而使BRCL4054ME处于低压降状态,则它实际上有可能延长充电时间.
图4示出了该电路是如何随着RCC的变大而导致电压下降的.
Whilethisapplicationdeliversmoreenergytothebatteryandreduceschargetimeinthermalmode,itmayactuallylengthenchargetimeinvoltagemodeifVCCbecomeslowenoughtoputtheBRCL4054MEintodropout.
Figure4showshowthiscircuitcanresultindropoutasRCCbecomeslarge.
Figure4.
ChargeCurrentvsRCC当为了保持较小的元件尺寸并避免发生压降而使RCC值最小化时,该技术能起到最佳的作用.
请牢记选择一个具有足够功率处理能力的电阻器.
ThistechniqueworksbestwhenRCCvaluesareminimizedtokeepcomponentsizesmallandavoiddropout.
Remembertochoosearesistorwithadequatepowerhandlingcapability.
VCC旁路电容器/VCCBypassCapacitor输入旁路可以使用多种类型的电容器.
然而,在采用多层陶瓷电容器时必须谨慎.
由于有些类型的陶瓷电容器具有自谐振和高Q值的特点,因此,在某些启动条件下(比如将充电器输入与一个工作中的电源相连)有可能产生高的电压瞬态信号.
增加一个与X5R陶瓷电容器串联的1.
5Ω电阻器将最大限度地减小启动电压瞬态信号.
Manytypesofcapacitorscanbeusedforinputbypassing,however,cautionmustbeexercisedwhenusingmultilayerceramiccapacitors.
Becauseoftheself-resonantandhighQcharacteristicsofsometypesofceramiccapacitors,highvoltagetransientscanbegeneratedundersomestart-upconditions,suchasconnectingthechargerinputtoalivepowersource.
Addinga1.
5ΩresistorinserieswithanX5Rceramiccapacitorwillminimizestart-upvoltagetransients.
Formoreinformation,refertoApplicationNote88.
BRCL4054MERev.
FApr.
-2020DATASHEEThttp://www.
fsbrec.
com19/25充电电流软启动/ChargeCurrentSoft-StartBRCL4054ME包括一个用于在充电循环开始时最大限度地减小涌入电流的软启动电路.
当一个充电循环被启动时,充电电流将在100μs左右的时间里从0上升至满幅全标度值.
在启动过程中,这能够起到最大限度地减小电源上的瞬变电流负载的作用.
TheBRCL4054MEincludesasoft-startcircuittominimizetheinrushcurrentatthestartofachargecycle.
Whenachargecycleisinitiated,thechargecurrentrampsfromzerotothefull-scalecurrentoveraperiodofapproximately100μs.
Thishastheeffectofminimizingthetransientcurrentloadonthepowersupplyduringstart-up.
CHRG引脚能够提供一个输入电压高于欠压闭锁门限电平的指示.
一个约20μA的弱下拉电流表示VCC引脚上施加了开始充电循环所需的足够电压.
当一个放电电池被连接到充电器时,充电循环的恒定电流部分开始,CHRG引脚电平被拉至地.
CHRG引脚能够吸收高达10mA的电流,以驱动一个用于指示充电循环正在进行之中的LED.
TheCHRGpincanprovideanindicationthattheinputvoltageisgreaterthantheundervoltagelockoutthresholdlevel.
Aweakpull-downcurrentofapproximately20μAindicatesthatsufficientvoltageisappliedtoVCCtobegincharging.
Whenadischargedbatteryisconnectedtothecharger,theconstantcurrentportionofthechargecyclebeginsandtheCHRGpinpullstoground.
TheCHRGpincansinkupto10mAtodriveanLEDthatindicatesthatachargecycleisinprogress.
当电池接近充满时,充电器进入充电循环的恒定电压部分,充电电流开始下降.
当充电电流降至不足设定电流的1/10时,充电循环结束且强下拉被一个20μA下拉所取代,表示充电循环已经结束.
如果输入电压被拿掉或降至欠压闭锁门限以下,则CHRG引脚变成高阻抗.
利用两个不同阻值的上拉电阻器,一个微处理器能够从该引脚检测出所有三种状态,如图5所示.
Whenthebatteryisnearingfullcharge,thechargerenterstheconstant-voltageportionofthechargecycleandthechargecurrentbeginstodrop.
Whenthechargecurrentdropsbelow1/10oftheprogrammedcurrent,thechargecycleendsandthestrongpull-downisreplacedbythe20μApull-down,indicatingthatthechargecyclehasended.
Iftheinputvoltageisremovedordropsbelowtheundervoltagelockoutthreshold,theCHRGpinbecomeshighimpedance.
Figure5showsthatbyusingtwodifferentvaluepull-upresistors,amicroprocessorcandetectallthreestatesfromthispin.
Figure5.
UsingaMicroprocessortoDetermineCHRGStateBRCL4054MERev.
FApr.
-2020DATASHEEThttp://www.
fsbrec.
com20/25CHRG状态输出引脚/CHRGStatusOutputPin为了在BRCL4054ME处于充电模式时进行检测,将数字输出引脚(OUT)强制为高电平并测量CHRG引脚上的电压.
即使在采用2k上拉电阻器的情况下,N沟道MOSFET也将把该引脚拉至低电平.
一旦充电循环终止,N沟道MOSFET即被关断,并且一个20μA的电流源被连接至CHRG引脚.
IN引脚随后将由2K上拉电阻器拉至高电平.
为了确定是否存在一个弱下拉电流,应将OUT引脚强制为高阻抗状态.
弱电流源将通过一个800K电阻器将IN引脚引脚拉至低电平;如果CHRG引脚为高阻抗,则IN引脚将被拉至高电平,表示器件处于一个UVLO状态.
TodetectwhentheBRCL4054MEisinchargemode,forcethedigitaloutputpin(OUT)highandmeasurethevoltageattheCHRGpin.
TheN-channelMOSFETwillpullthepinvoltagelowevenwiththe2kpull-upresistor.
Oncethechargecycleterminates,theN-channelMOSFETisturnedoffanda20μAcurrentsourceisconnectedtotheCHRGpin.
TheINpinwillthenbepulledhighbythe2kpull-upresistor.
Todetermineifthereisaweakpull-downcurrent,theOUTpinshouldbeforcedtoahighimpedancestate.
TheweakcurrentsourcewillpulltheINpinlowthroughthe800kresistor;ifCHRGishighimpedance,theINpinwillbepulledhigh,indicatingthatthepartisinaUVLOstate.
反向极性输入电压保护/ReversePolarityInputVoltageProtection在有些应用中,需要在VCC上进行反向极性电压保护.
如果电源电压足够高,则可采用一个串联隔离二极管.
在其他必须保持低降压的场合,可以采用一个P沟道MOSFET(如图6所示).
Insomeapplications,protectionfromreversepolarityvoltageonVCCisdesired.
Ifthesupplyvoltageishighenough,aseriesblockingdiodecanbeused.
Inothercases,wherethevoltagedropmustbekeptlowaP-channelMOSFETcanbeused(asshowninFigure6).
Figure6.
LowLossInputReversePolarityProtectionBRCL4054MERev.
FApr.
-2020DATASHEEThttp://www.
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com21/25USB和交流适配器电源/USBandWallAdapterPowerBRCL4054ME允许从一个交流适配器或一个USB端口进行充电.
图7示出了如何将交流适配器与USB电源输入加以组合的一个实例.
一个P沟道MOSFET(MP1)被用于防止交流适配器接入时信号反向传入USB端口,而一个肖特基二极管(D1)则被用于防止USB功率在经过1K下拉电阻器时产生损耗.
TheBRCL4054MEallowschargingfrombothawalladapterandaUSBport.
Figure7showsanexampleofhowtocombinewalladapterandUSBpowerinputs.
AP-channelMOSFET,MP1,isusedtopreventbackconductingintotheUSBportwhenawalladapterispresentandaSchottkydiode,D1,isusedtopreventUSBpowerlossthroughthe1kpull-downresistor.
一般来说,交流适配器能够提供比电流限值为500mA的USB端口大得多的电流.
因此,当交流适配器接入时,可采用一个N沟道MOSFET(MN1)和一个附加的10K设定电阻器来把充电电流增加至600mA.
Typicallyawalladaptercansupplymorecurrentthanthe500mA-limitedUSBport.
Therefore,anN-channelMOSFET,MN1,andanextra10kprogramresistorareusedtoincreasethechargecurrentto600mAwhenthewalladapterispresent.
Figure7.
CombiningWallAdapterandUSBPowerBRCL4054MERev.
FApr.
-2020DATASHEEThttp://www.
fsbrec.
com22/25典型应用/TypicalApplicationsBRCL4054MERev.
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-2020DATASHEEThttp://www.
fsbrec.
com23/25外形尺寸图/PackageDimensionsBRCL4054MERev.
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-2020DATASHEEThttp://www.
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com24/25印章说明/MarkingInstructions说明:4054:为型号代码****:为生产批号代码,随生产批号变化.
Note:4054:ProductType.
****:LotNo.
Code,codechangewithLotNo.
4054****BRCL4054MERev.
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-2020DATASHEEThttp://www.
fsbrec.
com25/25回流焊温度曲线图(无铅)/TemperatureProfileforIRReflowSoldering(Pb-Free)说明:Note:1、预热温度150~180℃,时间60~90sec;1.
Preheating:150~180,Time:60~90sec.
℃2、峰值温度245±5℃,时间持续为5±0.
5sec;2.
PeakTemp.
:245±5,Duration:5±0.
5sec.
℃3、焊接制程冷却速度为2~10/sec.
℃3.
CoolingSpeed:2~10/sec.
℃耐焊接热试验条件/ResistancetoSolderingHeatTestConditions温度:260±5℃时间:10±1sec.
Temp.
:260±5℃Time:10±1sec包装规格/PackagingSPEC.
卷盘包装/REELPackageType封装形式Units包装数量Dimension包装尺寸(unit:mm3)Units/Reel只/卷盘Reels/InnerBox卷盘/盒Units/InnerBox只/盒nnerBoxes/OuterBox盒/箱Units/OuterBox只/箱ReelInnerBox盒OuterBox箱SOT23-5/63,0001030,0004120,0007〞*8210*205*205435*225*420使用说明/Notices