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| ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietary information. unauthorized photocopy and duplication prohibited 5/2009 ?2009 belling all rights reserved 1 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 features programmablechargecurrentupto800ma no mosfet, sense resistor or blocking dioderequired preset 4.2v charge voltage with 1% accuracy charge current monitor output for gas gauging thermal regulation maximizes charge rate withoutriskofoverheating charges single cell liion batteries directly fromusbport overvoltageprotect automaticrecharge chargestatusoutputpin c/10chargetermination 25 m asupplycurrentinshutdown 2.9vtricklechargethreshold softstartlimitsinrushcurrent availablein5leadsot23package applications cellularandsmartphones chargingdocksandcradles bluetoothapplications pdas mp3/mp4/mp5players description the bl4054/BL4054B is a complete constant current/constantvoltagelinearchargerforsingl e cell lithiumion batteries. no external sense resistor is needed, and no blocking diode is requiredduetotheinternalmosfet architecture. thermal feedbackregulatesthechargecurrentto limit the die temperature during high power operation or high ambient temperature. the charge voltage is fixed at 4.2v, and the charge current can be programmed externally with a singleresistor.thebl4054/BL4054Bautomatical ly terminates the charge cycle when the charge currentdropsto1/10theprogrammedvalueafter thefinalfloatvoltageisreached. when the input supply (wall adapter or usb supply) is removed, the bl4054/BL4054B automaticallyentersalowcurrentstate,dropping the battery drain current to less than 2 ma . the bl4054/BL4054Bcanbeputintoshutdownmode, reducing the supply current to 25 m a. other features include charge current monitor, undervoltage lockout, automatic recharge and a status pin to indicate charge termination and the presenceofaninputvoltage. the only difference between bl4054 and BL4054B is that at power on, bl4054 will check the battery voltage first, it will not start chargi ng unless the battery voltage is below the autorechrage threshold. BL4054B does not perform this check. so BL4054B can guarantee thehighbatterycapacityatalltime,whilebl4054 can prevent the battery from being repeatedly chargedinsomespecificapplications. ordering information bl4054/BL4054BCxx x x xxx typical application 600ma 4.2v li-ion battery gnd prog bat v cc bl4054/BL4054B 1.65k 1uf v cc 4.5v to 6.5v 600ma application circuit package: rn:sot235 trn:tsot235 features: p:standard(default,leadfree) c:customized tricklecharge: t:tricklecharge n:notricklecharge floatvoltage: 42:4.2v 43:4.3v 44:4.4v
ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietary information. unauthorized photocopy and duplication prohibited 5/2009 ?2009 belling all rights reserved 2 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 absolute maximum rating (note 1) inputsupplyvoltage(v cc ) 0.3vto+10v progvoltage 0.3vto+v cc batvoltage 0.3vto7v chrgb 0.3vto10v batshortcircuitduration continuous batpincurrent 800ma progpincurrent 800 m a maximumjunctiontemperature 125c operatingtemperaturerange (note2) 40cto85c storagetemperaturerange 65cto125c leadtemperature(soldering,10s) 300c package information thermal resistance (note 4) package ? ja ? jc tsot235 220 c/w 110c/w sot235 250 c/w 130c/w note 1: absolutemaximumratingsarethosevaluesbeyondwh ichthelifeofadevicemaybeimpaired. note 2: thebl4054/BL4054Bisguaranteedtomeetperformanc especificationsfrom0cto70c.specificationso vertheC40cto 85coperatingtemperaturerangeareassuredbydes ign,characterizationandcorrelationwithstatisti calprocesscontrols. note 3: x:productcode(bl4054:b,BL4054B:b )v:voltagecode(4.2v:a,4.3v:b,4.4v:c)y:yearof manufacturing(9:2009)w:weekof manufacturing(w:az,az).contactbellingmarketin gformoreinformationindetail. note 4: thermalresistanceisspecifiedwithapproximately 1squareof1ozcopper. 1 2 3 5 4 tsot23-5/sot23-5 top view chrgb gnd bat prog v cc marking partnumber topmark temprange bl40544.2 bayw (note3) bl40544.3 bbyw bl40544.4 bcyw BL4054B4.2 b ayw BL4054B4.3 b byw BL4054B4.4 b cyw 40cto+85c ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietary information. unauthorized photocopy and duplication prohibited 5/2009 ?2009 belling all rights reserved 3 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 pin description pin name function 1 chrgb opendrain charge status output. when the battery i s charging, the chrgb pin is pulled low by an interna l nchannel mosfet. when the charge cycle is completed, a weak pulldown of approximately 12 m a is connectedtothechrgbpin,indicatinganacprese nt condition. when the bl4054/BL4054B detects an undervoltage lockout condition, chrgb is forced hi gh impedance. 2 gnd ground 3 bat charge current output. provides charge current to t he battery and regulates the final float voltage to 4. 2v. an internal precision resistor divider from this pin s ets the floatvoltagewhichisdisconnectedinshutdownmod e. 4 v cc positive input supply voltage. provides power to th e charger.v cc canrangefrom4.25vto6.5vandshouldbe bypassedwithatleasta1 m fcapacitor.whenv cc drops to within 30mv of the bat pin voltage, the bl4054/BL4054Bentersshutdownmode,droppingi bat to lessthan2 m a. 5 prog charge current program, charge current monitor and shutdown pin. the charge current is programmed by connectinga1%resistor,r prog ,fromthispintoground. whencharginginconstantcurrentmode,thispinse rvos to1v.inallmodes,thevoltageonthispincanbe usedto measurethechargecurrentusingthefollowingform ula: i bat =(v prog /r prog )?1000 the prog pin can also be used to shut down the charger.disconnectingtheprogramresistorfromgr ound allowsa3 m acurrenttopulltheprogpinhigh.whenit reaches the 1.21v shutdown threshold voltage, the charger enters shutdown mode, charging stops and th e input supply current drops to 25 m a. this pin is also clamped to approximately 2.4v. driving this pin to voltagesbeyondtheclampvoltage willdrawcurrent sas highas1.5ma.reconnectingr prog togroundwillreturn thechargertonormaloperation. ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietary information. unauthorized photocopy and duplication prohibited 5/2009 ?2009 belling all rights reserved 4 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 block diagram + + + + - - - - + ++ + - -- - + + + + - -- - + ++ + - -- - + ++ + - -- - + ++ + - -- - + ++ + - -- - + + + + - -- - ref 1.21v 7.0v ov_shdn 120 o c t die shdn standby to bat 2.9v ovp ta ca c1 c2 c3 chrgb 5ma 3ma v cc r5 r4 0.1v 1v r3 va ma 1x 1000x r1 r2 5 2 gnd prog 1 r prog 4 v cc 3 bat ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietary information. unauthorized photocopy and duplication prohibited 5/2009 ?2009 belling all rights reserved 5 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 electrical characteristics (note 5) (v cc =5v,t a =25c,unlessotherwisenoted.) symbol parameter conditions min typ max i splychrg chargemodesupplycurrent (note6) r prog =2k r prog =10k 300 m a 2000 m a 2000 m a i batchrg chargemodebatterycurrent r prog =2k r prog =10k 465ma 93ma 500ma 100ma 535ma 107ma v progchrg progpinvoltage r prog =2k r prog =10k 0.93v 0.93v 1v 1v 1.07v 1.07v i splystby standbymodesupplycurrent 100 m a 500 m a i batstby standbymodebatterycurrent 0 2.5 m a 6 m a i splymsd manualshutdownmodesupplycurrent 90 m a i batmsd manualshutdownmodebatterycurrent 2 m a 0 2 m a v progclmp progpinclampvoltage 2v 3v i splyasd automaticshutdownmodesupply current 25 m a 50 m a i batasd automaticshutdownmodebattery current 2 m a 0 2 m a i splyuvlo uvlomodesupplycurrent 25 m a 50 m a i batuvlo uvlomodebatterycurrent 2 m a 2 m a i batsleep sleepmodebatterycurrent 1 m a 1 m a v float floatvoltage 4.158v 4.2v 4.242v i trikl tricklechargecurrent r prog =2k r prog =10k 20ma 5ma 50ma 10ma 70ma 15ma v trikl tricklechargethreshold 2.8v 2.9v 3v v trikl,hys tricklechargehysteresis 60mv 100mv 150mv v uvlo uvlothreshold 3.7v 3.9v 4.1v v uvlo,hys uvlohysteresis 150mv 200mv 300mv v ovp inputovervoltageprotectthreshold 6.8v 7v 7.2v v ovp,hys inputovervoltageprotecthysteresis 200mv ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietary information. unauthorized photocopy and duplication prohibited 5/2009 ?2009 belling all rights reserved 6 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 v msd,rise manualshutdownthreshold,prog rising 1.15v 1.21v 1.3v v msd,fall manualshutdownthreshold,prog falling 0.95v 1.0v 1.05v v asd,rise automaticshutdownthreshold,bat rising 5mv 30mv 50mv v asd,fall automaticshutdownthreshold,bat falling 70mv 100mv 140mv i term c/10terminationcurrentthreshold 85mv 100mv 115mv v rechrg autorechargebatteryvoltage 4v 4.05v 4.1v i chrgb chrgbpinweakpulldowncurrent 8 m a 12 m a 35 m a v chrgb chrgbpinoutputlowvoltage 0.35v 0.6v t lim junctiontemperatureinconstant temperaturemode 120c r on powerfetonresistance 600m t ss softstarttime r prog =2k 50 m s t rechrg rechargecomparatorfiltertime 0.75ms 2ms 4.5ms t term terminationcomparatorfiltertime 0.4ms 1ms 2.5ms i prog progpinpullupcurrent 3 m a note 5: 100%productiontestat+25c. specificationsover thetemperaturerangeareguaranteedbydesignand characterization. note 6: supplycurrentincludesprogpincurrent(approxima tely100 m a)butdoesnotincludeanycurrentdeliveredtoth ebattery throughthebatpin(approximately100ma). typical performance characteristics 4.0 4.5 5.0 5.5 6.0 6.5 7.0 0.990 0.995 1.000 1.005 1.010 v prog (v) v cc (v) prog pin voltage vs supply voltage (constant current mode) v cc =5v v bat =4v t a =25 c r prog =10k 50 25 0 25 50 75 100 1.0000 1.0025 1.0050 1.0075 1.0100 1.0125 1.0150 1.0175 1.0200 v prog (v) temperature( c) prog pin voltage vs temperature v cc =5v v bat =4v r prog =10k 0.00 0.25 0.50 0.75 1.00 1.25 0 100 200 300 400 500 600 i bat (ma) v prog (v) charge current vs prog pin voltage v cc =5v t a =25 c r prog =2k ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietary information. unauthorized photocopy and duplication prohibited 5/2009 ?2009 belling all rights reserved 7 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 typical performance characteristics 50 25 0 25 50 75 100 125 2.7 3.0 3.3 3.6 3.9 4.2 4.5 i prog ( m a) temperature( c) prog pin pull-up current vs temperature and supply voltage v cc =6.5v v cc =4.2v v bat =4.3v v prog =0v 2.0 2.1 2.2 2.3 2.4 2.5 2.6 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 i prog ( ma ) v prog (v) prog pin current vs prog pin voltage (pull-up current) v cc =5v v bat =4.3v t a =25 c 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 300 250 200 150 100 50 0 i prog ( ma ) v prog (v) prog pin current vs prog pin voltage (clamp current) v cc =5v v bat =4.3v t a =25 c 0 100 200 300 400 500 600 4.15 4.17 4.19 4.21 4.23 4.25 v float (v) i bat (ma) regulated output (float) voltage vs charge current v cc =5v t a =25 c r prog =1.25k 50 25 0 25 50 75 100 4.185 4.190 4.195 4.200 4.205 4.210 4.215 v float (v) temperature( c) regulated output (float) voltage vs temperature v cc =5v r prog =10k 4.0 4.5 5.0 5.5 6.0 6.5 7.0 4.185 4.190 4.195 4.200 4.205 4.210 4.215 v float (v) v cc (v) regulated output (float) voltage vs supply voltage t a =25 c r prog =10k 0 1 2 3 4 5 6 7 0 5 10 15 20 25 30 35 40 i chrgb (ma) v chrgb (v) chrgb pin i-v curve (strong pull-down state) v cc =5v v bat =4v t a =25 c 50 25 0 25 50 75 100 125 20 22 24 26 28 30 32 34 36 38 40 i chrgb (ma) temperature( c) chrgb pin current vs temperature (strong pull-down state) v cc =5v v bat =4v v chrgb =1v 0 1 2 3 4 5 6 7 0 5 10 15 20 i chrgb ( m a) v chrgb (v) chrgb pin i-v curve (weak pull-down state) v cc =5v v bat =4.3v t a =25 c ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietary information. unauthorized photocopy and duplication prohibited 5/2009 ?2009 belling all rights reserved 8 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 typical performance characteristics 50 25 0 25 50 75 100 125 5 10 15 20 25 i chrgb ( ma) temperature( c) chrgb pin current vs temperature (weak pull-down state) v cc =5v v bat =4.3v v chrgb =5v 50 25 0 25 50 75 100 125 0 10 20 30 40 50 60 i trikl (ma) temperature( c) trickle charge current vs temperature r prog =2k r prog =10k v cc =5v v bat =2.5v 4.0 4.5 5.0 5.5 6.0 6.5 7.0 0 10 20 30 40 50 60 i trikl (ma) v cc (v) trickle charge current vs supply voltage r prog =2k r prog =10k v bat =2.5v t a =25 c 50 25 0 25 50 75 100 125 2.800 2.825 2.850 2.875 2.900 2.925 2.950 2.975 3.000 v trikl (v) temperature( c) trickle charge threshold vs temperature v cc =5v r prog =10k 2.7 3.0 3.3 3.6 3.9 4.2 4.5 0 100 200 300 400 500 600 i bat (ma) v bat (v) charge current vs battery voltage v cc =5v r prog =2k t a =25 c 4.0 4.5 5.0 5.5 6.0 6.5 7.0 0 100 200 300 400 500 600 i bat (ma) v cc (v) r prog =2k r prog =10k v bat =4v t a =25 c charge current vs supply voltage 50 25 0 25 50 75 100 125 150 0 100 200 300 400 500 600 i bat (ma) temperature( c) r prog =10k r prog =2k v cc =5v v bat =4v charge current vs ambient temperature 50 25 0 25 50 75 100 125 3.99 4.01 4.03 4.05 4.07 4.09 4.11 v rechrg (v) temperature( c) v cc =5v r prog =10k recharge voltage threshold vs temperature 50 25 0 25 50 75 100 125 350 400 450 500 550 600 650 700 r ds(on) (m w ) temperature( c) power fet "on" resistance vs temperature v cc =4.2v i bat =100ma r prog =2k ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietar y information. unauthorized photocopy and duplicati on prohibited 5/2009 ?2009 belling all rights reserved 9 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 operation the bl4054/BL4054B is a single cell lithiumionbatterychargerusingaconstant current / constant voltage algorithm. it can deliver up to 800ma of charge current (using a good thermal pcb layout) with a final float voltage accuracy of 1%. the ? bl4054/BL4054B includes an internal pchannel power mosfet and thermal regulation circuitry. no blocking diode or external current sense resistor is required; thus,thebasicchargercircuitrequiresonly twoexternalcomponents.furthermore,the bl4054/BL4054B is capable of operating fromausbpowersource. normal charge cycle achargecyclebeginswhenthevoltageat thev cc pinrisesabovetheuvlothreshold level and a 1% program resistor is connectedfromtheprogpintogroundor whenabatteryisconnectedtothecharger output.ifthebatpinislessthan2.9v,the charger enters trickle charge mode. in this mode, the bl4054/BL4054B supplies approximately1/10theprogrammedcharge current tobring thebattery voltage up to a safelevelforfullcurrentcharging. whenthebatpinvoltagerisesabove2.9v, the charger enters constantcurrent mode, where the programmed charge current is suppliedtothebattery.ifthebatteryvoltage isabove2.9vatpoweron,BL4054Benters the constantcurrent mode immediately, whilebl4054willperformonemorecheck. if the battery voltage is below the autorechargethreshold,bl4054entersthe constantcurrentmode,otherwiseitgoesto standby mode. this is the only difference between the bl4054 and BL4054B. refer tofigure1aand1bformoredetails. whenthebatpinapproachesthefinalfloat voltage(4.2v),thebl4054/BL4054Benters constantvoltage mode and the charge current begins to decrease. when the charge current drops to 1/10 of the programmedvalue,thechargecycleends. programming charge current thechargecurrentisprogrammedusinga singleresistorfromtheprogpintoground. the battery charge current is 1000 times the current out of the prog pin. the programresistorandthechargecurrentare calculatedusingthefollowingequations: chg prog i v 1000 r = prog chg r v 1000 i = thechargecurrentoutofthebatpincan bedeterminedatanytimebymonitoringthe prog pin voltage using the following equation: 1000 r v i prog prog bat = charge termination a charge cycle is terminated when the chargecurrentfallsto1/10theprogrammed valueafterthefinalfloatvoltageisreached. this condition is detected by using an internal, filtered comparator to monitor the prog pin. when the prog pin voltage falls below 100mv for longer than t term (typically1ms),chargingisterminated.the charge current is latched off and the bl4054/BL4054B enters standby mode, where the input supply current drops to 100 m a. (note: c/10 termination is disabled intricklechargingmode). whencharging,transientloadsonthebat ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietar y information. unauthorized photocopy and duplicati on prohibited 5/2009 ?2009 belling all rights reserved 10 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 pin can cause the prog pin to fall below 100mvforshortperiodsoftimebeforethe dcchargecurrenthasdroppedto1/10the programmed value. the 1ms filter time (t term ) on the termination comparator ensures that transient loads of this nature do not result in premature charge cycle termination. once the average charge current drops below 1/10 the programmed value,thebl4054/BL4054Bterminatesthe charge cycle and ceases to provide any currentthroughthebatpin.inthisstate,all loads on the bat pin must be supplied by thebattery. the bl4054 constantly monitors the bat pinvoltageinstandbymode.ifthisvoltage drops below the 4.05v recharge threshold (v rechrg ),anotherchargecyclebeginsand currentisonceagainsuppliedtothebattery. tomanuallyrestartachargecyclewhenin standby mode, the input voltage must be removedandreapplied,orthechargermust be shut down and restarted using the prog pin. figure 1a and 1b shows the statediagramofatypicalchargecycle. 1/10 full current chrgb:strong pull-down full current chrgb:strong pull-down no charge current chrgb:weak pull-down 2.9v ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietar y information. unauthorized photocopy and duplicati on prohibited 5/2009 ?2009 belling all rights reserved 11 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 prog pin. this reduces the battery drain current to less than 2 m a and the supply current to less than 50 m a. a new charge cycle can be initiated by reconnecting the programresistor. inmanualshutdown,thechrgbpinisina weakpulldownstateaslongasv cc ishigh enough to exceed the uvlo conditions. the chrgb pin is in a high impedance state if the bl4054/BL4054B is in under voltage lockout mode: either v cc is within 100mvofthebatpinvoltageorinsufficient voltageisappliedtothev cc pin. over-voltage protect the bl4054/BL4054B has an internal overvoltageprotectcomparator,oncethe inputvoltagev cc risesabove7v(v ovp ),this comparator will shut down the chip. this feature can prevent the bl4054/BL4054B fromtheovervoltagestressduetotheinput transient at hot plug in. in this state, the chrgb pin will be high impedance. once thev cc fallsbacktosaferange(v ovp v ovp, hys ),normaloperationcontinues. automatic recharge once the charge cycle is terminated, the bl4054/BL4054Bcontinuouslymonitorsthe voltageonthebatpinusingacomparator with a 2ms filter time (t rechrg ). a charge cyclerestartswhenthebatteryvoltagefalls below 4.05v (which corresponds to approximately80%to90%batterycapacity). this ensures that the battery is kept at or near a fully charged condition and eliminates the need for periodic charge cycle initiations. chrgb output enters a strong pulldown state during recharge cycles. applications information stability considerations the constantvoltage mode feedback loop is stable without an output capacitor provided a battery is connected to the chargeroutput.withnobatterypresent,an outputcapacitorisrecommendedtoreduce ripple voltage.when using high value, low esrceramiccapacitors,itisrecommended to add a 1 w resistor in series with the capacitor. no series resistor is needed if tantalumcapacitorsareused. inconstantcurrentmode,theprogpinis in the feedback loop, not the battery. the constantcurrent mode stability is affected bytheimpedanceattheprogpin.withno additional capacitance on the prog pin, the charger is stable with program resistor valuesashighas20k.however,additional capacitance on this node reduces the maximum allowed program resistor thus it shouldbeavoided. average,ratherthaninstantaneous,charge current may be of interest to the user. for example, if a switching power supply operatinginlowcurrentmodeisconnected in parallel with the battery, the average current being pulled out of the bat pin is typically of more interest than the instantaneous current pulses. in such a case,asimplercfiltercanbeusedonthe prog pin to measure the average battery currentasshowninfigure2.a10kresistor has been added between the prog pin andthefiltercapacitortoensurestability. thermal limiting an internal thermal feedback loop reduces the programmed charge current if the die ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietar y information. unauthorized photocopy and duplicati on prohibited 5/2009 ?2009 belling all rights reserved 12 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 temperatureattemptstoriseaboveapreset valueofapproximately120 c.thisfeature protects the bl4054/BL4054B from excessivetemperatureandallowstheuser to push the limits of the power handling capability of a given circuit board without riskofdamagingthebl4054/BL4054B.the charge current can be set according to typical (not worstcase) ambient temperature with the assurance that the charger will automatically reduce the currentinworstcaseconditions. prog bl4054 gnd r prog c filter 10k charge current monitor circuitry figure2.isolatingcapacitiveloadonprogpin power dissipation the conditions that cause the bl4054/BL4054Btoreducechargecurrent through thermal feedback can be approximated by considering the power dissipatedintheic.nearlyallofthispower dissipation is generated by the internal mosfetthis is calculated to be approximately: bat bat cc d i ) v v ( p - = wherep d isthepowerdissipated,v cc isthe input supply voltage, v bat is the battery voltage and i bat is the charge current. the approximate ambient temperature at which the thermal feedback begins to protect the icis: ja d a p c 120 t q - = ja bat bat cc a i ) v v ( c 120 t q - - = example: an bl4054/BL4054B operating from a 5v usb supply is programmed to supply 400ma fullscale current to a discharged liion battery with a voltage of 3.75v. assuming q ja is 150 c/w, the ambient temperature at which the bl4054/BL4054B will begin to reduce the chargecurrentisapproximately: w / c 150 ma 400 ) v 75 .3 v 5( c 120 t a - - = c 45 t a = the bl4054/BL4054B can be used above 45 cambient,butthechargecurrentwillbe reduced from 400ma. the approximate currentatagivenambienttemperaturecan beapproximatedby: ja bat cc a bat ) v v ( t c 120 i q - - = using the previous example with an ambient temperature of 60 c, the charge currentwillbereducedtoapproximately: ma 320 w / c 150 ) v 75 .3 v 5( c 60 c 120 ibat = - - = moreover, when thermal feedback reduces thechargecurrent,thevoltageattheprog pin is also reduced proportionally as discussedintheoperationsection. it is important to remember that bl4054/BL4054B applications donot need to be designed for worstcase thermal conditions since the ic will automatically reducepowerdissipationwhenthejunction temperaturereachesapproximately120 c. thermal considerations because of the small size of the thinsot package,itisveryimportanttouseagood ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietar y information. unauthorized photocopy and duplicati on prohibited 5/2009 ?2009 belling all rights reserved 13 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 thermal pc board layout to maximize the available charge current. the thermal path fortheheatgeneratedbytheicisfromthe die to the copper lead frame, through the packageleads,(especiallythegroundlead) to the pc board copper. the pc board copperistheheatsink.thefootprintcopper pads should be as wide as possible and expandouttolargercopperareastospread and dissipate the heat to the surrounding ambient. feedthrough vias to inner or backside copper layers are also useful in improving the overall thermal performance of the charger. other heat sources on the board,notrelatedtothecharger,mustalso beconsideredwhendesigningapcboard layout because they will affect overall temperature rise and the maximum charge current. the following table lists thermal resistance forseveraldifferentboardsizesandcopper areas. allmeasurementsweretakeninstillairon 3/32" fr4 board with the device mounted ontopside. table 1. measured thermal resistance (2-layer board * ) copper area topside backside board area thermal resistance junction-to-ambient 2500mm 2 2500mm 2 2500mm 2 125 /w 1000mm 2 2500mm 2 2500mm 2 125 /w 225mm 2 2500mm 2 2500mm 2 130 /w 100mm 2 2500mm 2 2500mm 2 135 /w 50mm 2 2500mm 2 2500mm 2 150 /w * eachlayerusesoneouncecopper table 2. measured thermal resistance (4-layer board ** ) copper area (each side) board area thermal resistance junction-to-ambient 2500mm 2*** 2500mm 2 80 /w **topandbottomlayersusetwoouncecopper,inner layersuse oneouncecopper ***10,000mm 2 totalcopperarea v cc bypass capacitor many types of capacitors can be used for input bypassing,however, cautionmust be exercised when using multilayer ceramic capacitors. because of the selfresonant andhighqcharacteristicsofsometypesof ceramic capacitors, high voltage transients can be generated under some startup conditions,suchasconnectingthecharger input to a live power source. adding a 1 w resistor in series with an x5r ceramic capacitor will minimize startup voltage transients. charge current soft-start the bl4054/BL4054B includes a softstart circuittominimizetheinrushcurrentatthe start of a charge cycle. when a charge cycle is initiated, the charge current ramps from zero to the fullscale current over a periodofapproximately50 m s.thishasthe effect of minimizing the transient current loadonthepowersupplyduringstartup. ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietar y information. unauthorized photocopy and duplicati on prohibited 5/2009 ?2009 belling all rights reserved 14 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 typical applications prog bl4054 BL4054B gnd bat v cc 1uf 2k li-ion cell 500ma 3 5 2 4 full featured single cell li full featured single cell li full featured single cell li full featured single cell li- -- -ion charger ion charger ion charger ion charger shdn 330 chrgb v in =5v 1 prog bl4054 BL4054B gnd bat v cc 5v wall adapter usb power 1uf 1k 10k 2.5k li-ion cell i bat 3 5 2 4 usb usb usb usb/ // /wall adapter power li wall adapter power li wall adapter power li wall adapter power li- -- -ion charger ion charger ion charger ion charger chrgb bl4054 BL4054B v cc v + 800k using a microprocessor to determine chrgb state using a microprocessor to determine chrgb state using a microprocessor to determine chrgb state using a microprocessor to determine chrgb state 2k v dd uprocessor out in prog bl4054 BL4054B gnd bat v cc 5v wall adapter 1uf 2k li-ion cell 500ma 3 5 2 4 basic li basic li basic li basic li- -- -ion charger ion charger ion charger ion charger with reverse polarity input protection with reverse polarity input protection with reverse polarity input protection with reverse polarity input protection prog bl4054 BL4054B gnd bat v cc v in =5v 1uf 1.25k li-ion cell 800ma 3 5 2 4 800 800 800 800ma li ma li ma li ma li- -- -ion charger ion charger ion charger ion charger with external power dissipation with external power dissipation with external power dissipation with external power dissipation w 25 . 0 uc 500ma 100ma/ ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietar y information. unauthorized photocopy and duplicati on prohibited 5/2009 ?2009 belling all rights reserved 15 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 package description tsot235surfacemountpackage ppmic bu www.belling.com.cn bl4054/BL4054B rev 1.4 belling proprietar y information. unauthorized photocopy and duplicati on prohibited 5/2009 ?2009 belling all rights reserved 16 bl4054/BL4054B 800ma standalone linear li-ion battery charger with thermal regulation in sot23-5/tsot23-5 dimensions in millimeters dimensions in inches symbol min max min max a 0.889 1.295 0.035 0.051 a1 0.000 0.152 0.000 0.006 b 1.397 1.803 0.055 0.071 b 0.356 0.559 0.014 0.022 c 2.591 2.997 0.102 0.118 d 2.692 3.099 0.106 0.122 e 0.838 1.041 0.033 0.041 h 0.080 0.254 0.003 0.010 l 0.300 0.610 0.012 0.024 sot235surfacemountpackage |
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