BQ24702资料

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元器件交易网www.cecb2b.comActual Size(6,60 mm x 7,90 mm)bq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005MULTICHEMISTRY BATTERY CHARGER CONTROLLERAND SYSTEM POWER SELECTORFEATURESDDynamic Power Management, DPMDDDDDDDDDDESCRIPTIONThe bq24702/bq24703 is a highly integrated batterycharge controller and selector tailored for notebook andsub-notebook PC applications.The bq24702/bq24703 uses dynamic powermanagement (DPM) to minimize battery charge time bymaximizing use of available wall-adapter power. This isachieved by dynamically adjusting the battery chargecurrent based on the total system (adapter) current.The bq24702/bq24703 uses a fixed frequency, pulsewidth modulator (PWM) to accurately control batterycharge current and voltage. Charge current limits canbe programmed from a keyboard controller DAC or byexternal resistor dividers from the precision 5-V, ±0.6%,externally bypassed voltage reference (VREF),supplied by the bq24702/bq24703.Minimizes Battery Charge TimeIntegrated Selector Supports BatteryConditioning and Smart Battery Learn CycleZero Volt OperationSelector Feedback Circuit EnsuresBreak-Before-Make Transition±0.4% Charge Voltage Accuracy, Suitable forCharging Li-Ion Cells±4% Charge Current Accuracy300-kHz Integrated PWM Controller forHigh-Efficiency Buck RegulationDepleted Battery Detection and Indication toProtect Battery From Over Discharge20-µA Sleep Mode Current for Low BatteryDrain24-Pin TSSOP Package and 5 mm × 5 mmQFN package (bq24703 only)ENABLEBATDEPBATSET6SRSETACSETbq24702, bq24703PW PACKAGE(TOP VIEW)bq24703RHD PACKAGE(BOTTOM VIEW)12345212019181716NC − No internal connectionPWMVSVHSPSRPALARM Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of TexasInstrumentssemiconductor products and disclaimers thereto appears at the end of this data sheet.Copyright  2003 − 2004, Texas Instruments IncorporatedPRODUCTION DATA information is current as of publication date.Products conform to specifications per the terms of Texas Instrumentsstandard warranty. Production processing does not necessarily includetesting of all parameters.GNDSRN15ACDETACPRESACSELBATDEPSRSETACSETVREFENABLEBATSETCOMPACNACP1234 567101112242322212019181716151413ACDRVBATDRVVCCPWMVHSPALARMVSGNDSRPSRNIBATBATPACSELACPRESACDETACDRVBATDRVNCVCC7COMPVREF282726252423221011121314ACNACPNCNCBATPIBATNCwww.ti.com1元器件交易网www.cecb2b.combq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005DESCRIPTION (continued)The battery voltage limit can be programmed by using the internal 1.196-V, ±0.5% precision reference, making itsuitable for the critical charging demands of lithium-ion cells. Also, the bq24702/bq24703 provides an option tooverride the precision reference and drive the error amplifier either directly from an external reference or from aresistor divider off the 5 V supplied by the integrated circuit.The selector function allows the manual selection of the system power source, battery or wall-adapter power. Thebq24702/bq24703 supports battery-conditioning and battery-learn cycles through the ACSEL function. The ACSELfunction allows manual selection of the battery or wall power as the main system power. It also provides autonomousswitching to the remaining source (battery or ac power) should the selected system power source terminate (referto Table 1 for the differences between the bq24702 and the bq24703). The bq24702/bq24703 also provides an alarmfunction to indicate a depleted battery condition.The bq24702/bq24703 PWM controller is ideally suited for operation in a buck converter for applications when thewall-adapter voltage is greater than the battery voltage.DISSIPATION RATINGSMAXIMUM POWER DISSIPATION(HIGH K BOARD)vsFREE-AIR TEMPERATUREMaximum Power Dissipation (High K Board) − WMaximum Power Dissipation (Low K Board) − W1.601.401.2010.800.600.400.200θJA = .37 C/W @ 0 LFM,θJA = 77.98 C/W @ 150 LFM,θJA = 73.93 C/W @ 250 LFM,θJA = 68.23 C/W @ 500 LFMMAXIMUM POWER DISSIPATION(LOW K BOARD)vsFREE-AIR TEMPERATURE1.401.2010.800.600.400.200θJA = 150.17 C/W @ 0 LFM,θJA = 110.95 C/W @ 150 LFM,θJA = 99.81 C/W @ 250 LFM,θJA = 86.03 C/W @ 500 LFMMAX Pd (W) @ 500 LFMMAX Pd (W) @ 250 LFMMAX Pd (W) @ 150 LFMMAX Pd (W) @ 0 LFMMAX Pd (W) @ 500 LFMMAX Pd (W) @ 250 LFMMAX Pd (W) @ 150 LFMMAX Pd (W) @ 0 LFM255070TA − Free-Air Temperature − °C8525507085TA − Free-Air Temperature − °C†The JEDEC low K (1s) board design used to derive this data was a 3-inch x 3-inch, two layer board with 2 ounce copper traces on top of the board.‡The JEDEC high K (1s) board design used to derive this data was a 3-inch x 3-inch, multilayer board with 1 ounce internal power and groundplanes and 2 ounce copper traces on top and bottom of the board.2www.ti.com元器件交易网www.cecb2b.comSLUS553D − MAY 2003 − REVISED JULY 2005bq24702, bq24703Table 1. Available OptionsCONDITION−20°C ≤ TJ ≤ 125°CBattery as Power SourceBattery removalBattery reinsertedAC as Power SourceAC removalAC reinsertedDepleted Battery ConditionBattery as power sourceAC as power sourceALARM Signal ActiveDepleted battery conditionWhen selector input is not equal to selector output (single pulse alarm)Depleted battery conditionSends ALARM signalSends ALARM signalAutomatically selects acSends ALARM signalSends ALARM signalAutomatically selects batterySelection based on selector inputsAutomatically selects batterySelection based on selector inputsAutomatically selects ac + alarmSelection based on selector inputsAutomatically selects ac + alarmAdapter latched until adapter is removed or ac selecttoggles.SELECTOR OPERATIONbq24702PWbq24703RHDABSOLUTE MAXIMUM RATINGS OVER OPERATING FREE-AIR TEMPERATURE (unless otherwise noted)Ĕ}Supply voltage range: VCC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.3 V to 30 VBattery voltage range: SRP, SRN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.3 V to 30 VInput voltage: ACN, ACP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.3 V to 30 VVirtual junction temperature range, TJ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −40°C to 125°CMaximum source/sink current VHSP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 mAMaximum ramp rate for VCC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 V/ µsMaximum sink current ACPRES, COMP, ALARM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 mAMaximum ramp rate for V(BAT). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 V/ µsMaximum source/sink current BATDRV. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 mAMaximum source/sink current ACDRV. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 mAMaximum source/sink current PWM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 mAMaximum source/sink current pulsed ACDRV, (10-µs rise time, 10-µs fall time, 1-ms pulse width, single pulse) 50 mAMaximum source current VREF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 mAMaximum source current SRP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 mAMaximum difference voltage SRP − SRN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 VStorage temperature range Tstg. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65°C to 150°CLead temperature (soldering, 10 seconds). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300°C†Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, andfunctional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is notimplied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.‡All voltages are with respect to ground. Currents are positive into and negative out of the specified terminals. Consult the Packaging section ofthe data book for thermal limitations and considerations of the package.www.ti.com3元器件交易网www.cecb2b.combq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005RECOMMENDED OPERATING CONDITIONS (TA = TOPR) all voltages relative to VssMINSupply voltage, (VCC)Negative ac current sense, (ACN)Positive ac current sense, (ACP)Negative battery current sense, (SRN)Positive battery current sense, (SRP)AC or adapter power detection (ACDET)AC power indicator (ACPRES)AC adapter power select (ACSEL)Depleted battery level (BATDEP)Battery charge current programming voltage (SRSET)Charge enable (ENABLE)External override to an internal 0.5% precision reference (BATSET)Inverting input to the PWM comparator (COMP)Battery charge regulation voltage measurement input to the battery—voltage gm amplifier (BATP)Battery current differential amplifier output (IBAT)System load voltage input pin (VS)Depleted battery alarm output (ALARM)Gate drive output (PWM)Battery power source select output (BATDRV)AC or adapter power source selection output (ACDRV)ACSETOperating free-air temperature, TAAnalog and PWM operationSelector operation7.04.57.07.055000000000000VHSP0VHSP0−40MAX28282828282855552.552.55552.55VCC28VCC2.585UNITVVVVVVVVVVVVVVVVVVVVV°C4www.ti.com元器件交易网www.cecb2b.comSLUS553D − MAY 2003 − REVISED JULY 2005bq24702, bq24703ELECTRICAL CHARACTERISTICS (−40°C ≤ TJ ≤ 125°C, 7.0 VDC ≤ VCC ≤ 28 VDC, all voltages relative to Vss) (unless otherwise specified)Quiescent CurrentPARAMETERIDD(OP)IDD(SLEEP)Total chip operating currentTotal battery sleep current, ac not presentTEST CONDITIONSACPRES = High, EN = 0ACPRES = LowMIN1TYP1.622MAX628UNITmAµAlogic interface dc characteristicsPARAMETERVOLVILVIHI(SINK1)I(SINK2)Low-level output voltage (ACPRES, ALARM)Low-level input voltage (ACSEL, ENABLE)High-level input voltage (ACSEL, ENABLE)Sink current (ACPRES)Sink current (ALARM)VOL = 0.4VOL = 0.4TEST CONDITIONS0°C ≤ TJ ≤ 85°C−40°C ≤ TJ ≤ 125°C1.81.51.5222.52.5IOL = 1 mATEST CONDITIONSMINTYPMAX0.40.6UNITVVVmAmAPWM OscillatorPARAMETERfOSC(PWM)Oscillator frequencyMaximum duty cycleInput voltage for maximum dc (COMP)Minimum duty cycleInput voltage for minimum dc (COMP)V(RAMP)VIK(COMP)IS(COMP)Oscillator ramp voltage (peak-to-peak)Internal input clamp voltage (tracks COMP voltage for maximum dc)Internal source current (COMP)Error amplifier = OFF, V(COMP) = 1 VTEST CONDITIONSV(ACDET) = 5 VV(SRSET) = 2.5 VV(ACSET) = 2.5 VV(BATDEP) = 5 VV(VS) = 5 VV(ALARM) = 5 VV(ACSEL) = 5 VV(ENABLE) = 5 VV(ACPRES) = 5 VV(BATP) = 5 VV(BATSET) = 2.5 V701.852.153.8110MIN260240100%3.80%0.82.304.5140µAVVTYP300300MAX340350UNITkHzLeakage CurrentPARAMETERIL(ACDET)IL(SRSET)IL(ACSET)IL(BATDEP)IL(VS)IL(ALARM)IL(ACSEL)IL(ENABLE)IL(ACPRES)IL(BATP)IL(BATSET)Leakage current, ACDETLeakage current, SRSETLeakage current, ACSETLeakage current, BATDEPLeakage current, VSLeakage current, ALARMLeakage current, ACSELLeakage current, ENABLELeakage current, ACPRESLeakage current, BATPLeakage current, BATSETMINTYPMAX0.20.20.20.20.20.20.20.20.20.20.2UNITµAµAµAµAµAµAµAµAµAµAµAwww.ti.com5元器件交易网www.cecb2b.combq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005ELECTRICAL CHARACTERISTICS (CONTINUED)(−40°C ≤ TJ ≤ 125°C, 7.0 VDC ≤ VCC ≤ 28 VDC, all voltages relative to Vss) (unless otherwise specified)Battery Current-Sense AmplifierPARAMETERgmCMRRVICRI(SINK)Transconductance gainCommon-mode rejection ratioCommon-mode input (SRP, SRN)voltage rangeSink current (COMP)Input bias current (SRP), See Note 2IIBInput bias current accuracy(ISRP − ISRN)Battery current programming voltage(SRSET)Battery current set gainTotal battery current-sense mid-scaleaccuracyTotal battery current-sense full-scaleaccuracy0.65 V ≤ SRSET ≤ 2.5 V, 8 V ≤ SRN ≤ 16 V,See Note 3SRSET = 1.25 V, TJ = 25°C, See Note 4SRSET = 1.25 V, See Note 4SRSET = 2.5 V, TJ = 25°C, See Note 4SRSET = 2.5 V, See Note 4See Note 1VCC = SRN, SRP + 2 VCOMP = 1 V,V(SRP) = 16 V,(SRP − SRN) = 100 mV(SRP − SRN) = 10 mVSRSET = 2.5 V,VCC = 2850.570−3024−5%−6%−3%−4%251.5850TEST CONDITIONSMIN75TYP12090302.5110µA32.5265%6%3%4%VV/VMAX175UNITmA/VdBVmA(SRP − SRN) = 100 mV, SRSET= 2.5 V,VCC = 28 V, 0 ≤ TJ ≤ 125°CV(SET)AVNOTES:1.Specified by design. Not production tested.2I(SRP) = I(SRN) = (V(SRSET) / 50 kΩ) + ((V(SRP) − V(SRN) / 3 kΩ)example: If (V(SRSET) = 2.5 V) , (V(SRP) − V(SRN) = 100 mV) Then I(SRP) = I(SRN) = 83 µA3.I+SRSET 1BATARVSENSE4.Total battery-current set is based on the measured value of (SRP−SRN) = ∆m, and the calculated value of (SRP−SRN) = ∆C, using(Dm*Dc)the measured gain, AV. Dc+SRSET,Totalaccuracyin%+ 100,I(SRP)*I(SRN)+0DcAV6www.ti.com元器件交易网www.cecb2b.comSLUS553D − MAY 2003 − REVISED JULY 2005bq24702, bq24703ELECTRICAL CHARACTERISTICS (CONTINUED)(−40°C ≤ TJ ≤ 125°C, 7.0 VDC ≤ VCC ≤ 28 VDC, all voltages relative to Vss) (unless otherwise specified)Adapter Current-Sense AmplifierPARAMETERgmCMRRVICRI(SINK)Transconductance gainCommon-mode rejection ratioCommon-mode input voltage range (ACP)Sink current (COMP)Input bias current (ACP, ACN)IIBV(SET)AVInput bias current accuracy ratio(I(ACP), I(ACN))AC current programming voltage (ACSET)AC current set gainTotal ac current-sense mid-scale accuracyTotal ac current-sense full-scale accuracy0.65 V ≤ ACSET ≤ 2.5 V, 12 V ≤ ACP ≤ 20 V,See Note 5ACSET = 1.25 V, TJ = 25°C, See Note 6ACSET = 1.25 V, See Note 6ACSET = 2.5 V, TJ = 25°C, See Note 6ACSET = 2.5 V, See Note 6COMP = 1 V, (ACP − ACN) = 10 mVACP = ACN = 28 V, VCC = 28 V, ACSET = 2.5 VACP = ACN = 28 V, VCC = 28 V,ACSET = 2.5 V, 0 ≤ TJ ≤ 125°CSee Note 17.00.540−3024.5−5%−6%−3.5%−4%25.31.5500TEST CONDITIONSMIN75TYP13090VCC2.565µA32.526.55%6%3.5%4%VV/VMAX175UNITmA/VdBVmABattery Voltage Error AmplifierPARAMETERgmCMRRVICRVITI(SINK)Transconductance gainCommon-mode rejection ratioBATSET common-mode input voltage rangeInternal reference override input threshold voltageSink current COMPCOMP = 1 V,(BATP − BATSET) = 10 mV, BATSET = 1.25 VTJ = 25°CTJ = 0°C to 85°CTJ = −40°C to 125°CNOTE:5.Calculation of the ac current: IACSee Note 1 10.200.51.1901.1831.1780.251.51.1961.1961.196TEST CONDITIONSMIN75TYP135902.50.352.51.2021.2031.204VMAX175UNITmA/VdBVVmAV(FB)Error-amplifier precision reference voltage+ACSET 1RAVSENSE6.Total ac-current set accuracy is based on the measured value of (ACP−ACN) = ∆c, using the measured gain, AV.(Dm*Dc)Dc+ACSET,Totalaccuracyin%+ 100,I(ACP)*I(ACN)+0DcAVwww.ti.com7元器件交易网www.cecb2b.combq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005ELECTRICAL CHARACTERISTICS (CONTINUED)(−40°C ≤ TJ ≤ 125°C, 7.0 VDC ≤ VCC ≤ 28 VDC, all voltages relative to Vss) (unless otherwise specified)Battery Current Output AmplifierPARAMETERG(TR)VI(BAT)Transfer gainBattery current readback outputvoltage (IBAT)Line rejection voltageCMVO(IBAT)IS(O)Common-mode input range (SRP)Battery current output voltage range(IBAT)Output source current (IBAT)(SRP − SRN) = 100 mV(SRP − SRN) = 50 mV, TJ = 25°C, See Note 7(SRP − SRN) = 50 mV, 0°C ≤ TJ ≤ 85°C(SRP − SRN) = 100 mV, TJ = 25°C, See Note 7(SRP − SRN) = 100 mV, 0°C < TJ < 85°CTEST CONDITIONS(SRP − SRN) = 5 mV, See Note 7(SRP − SRN) = 5 mV, SRP = 12 V, VCC = 18 V, TJ = 25°CTJ = 25°C505−3%−20%−1.5%−6%7.1MINTYP2010010282.59.42.4%20%1.2%8.5%MAXUNITV/VmVmV/VVVmATotal battery current readbackfull-scale accuracy5-V Voltage ReferencePARAMETERTEST CONDITIONSTJ = 25°CTJ = 0°C to 85°CTJ = 40°C to 85°CTJ = −40°C to 125°CILOAD = 5 mA1 mA ≤ ILOAD ≤ 5 mA8CapacitanceESR2.25MIN4.9854.94.94.926TYP55550.11.120MAX5.0135.0135.035.030.37430101000UNITVVVmV/VmV/mAmAµFmΩVrefOutput voltage (VREF)Line regulationLoad regulationShort circuit current5V REF output capacitorOutput capacitor equivalent resistorHalf Supply RegulatorPARAMETERV(HSP)NOTE:Voltage regulationTEST CONDITIONSMINVCC − 11TYPVCC − 10.2MAXVCC − 8.51.5UNITVI(SINK) = 20 mA, VCC = 18 VI(SINK) = 1 mA, VCC = 7 VVIBAT7.Battery readback transfer gain G+TR(SRP*SRN)8www.ti.com元器件交易网www.cecb2b.comSLUS553D − MAY 2003 − REVISED JULY 2005bq24702, bq24703ELECTRICAL CHARACTERISTICS (CONTINUED)(−40°C ≤ TJ ≤ 125°C, 7.0 VDC ≤ VCC ≤ 28 VDC, all voltages relative to Vss) (unless otherwise specified)MOSFET Gate DrivePARAMETERAC driver RDS(on) highAC driver RDS(on) lowBattery driver RDS(on) highBattery driver RDS(on) lowtdatdbVOHTime delay from ac driver off to batterydriver onTime delay from battery driver off to acdriver onPWM driver high-level output voltagePWM driver RDS(on) highVOLPWM driver low-level output voltagePWM driver RDS(on) lowIO = 10 mA, VCC = 18 VIO = 50 mA, VCC = 18 VTEST CONDITIONSVCC = 18 V, I(ACDRV) = 1 mAVCC = 18 V, I(ACDRV) = 1 mAVCC = 18 V, I(BATDRV) = 1 mAVCC = 18 V, I(BATDRV) = 1 mAACSEL 2.4 V ⇓0.2 VACSEL 0.2 V ⇑ 2.4 VIO = −10 mA, VCC = 18 VIO = −50 mA, VCC = 18 VVCC −0.18VCC −1.2MINTYP8555315701.22.4VCC −0.09VCC −0.87VHSP+0.1VHSP+0.6514VHSP+0.4VHSP+1.28.5MAX15011060011523.3UNITΩΩΩΩµsµsVΩVΩSelectorPARAMETERV(ACPRES)VIT(ACPRES)td(ACPRES)V(BATDEP)V(NOBAT)t(BATSEL)t(ACSEL)V(VS)VIT(VS)AC presence detect voltageAC presence hysteresisDeglitch delay for adapter insertionBattery depletion ALARM trip voltageNo battery detect, switch to ACDRVBattery select time (ACSEL low to BATDRV low)AC select time (ACSEL high to ACDRV low)VS voltage to enable BATDRVVS voltage hysteresisSee Note 8−40°C to 85°Cbq24702 only, See Note 8−40°C to 85°CVS < BATP, 50% threshold,ACSEL 2.4 V ⇓ 0.2 VACSEL 0.2 V ⇑ 2.4 VBATP = 1 VVS > BATP1.1941.2080.8690.880110.9820TEST CONDITIONS−40°C to 85°CMIN1.1941.208TYP1.2461.2461%1001.2461.246112.52.51351.2861.2851.1441.1183.53.51.0285µsVVµsµsVmVMAX1.2861.285UNITVZero Volt OperationPARAMETERrDS(on)Static drain source on-state resistancezero volt operation thresholdTEST CONDITIONSVCC = 7 V, TJ = 125°C, IO = 100 mABATDEP increasingBATDEP decreasingMIN0.7430.570TYP5.30.7940.62MAX8.70.8400.656UNITΩVNOTES:8.Total battery current readback accuracy is based on the measured value of VIBAT, VIBATm, and the calculated value of VIBAT, VIBATc, using the measured value of the transfer gain, GTR.V*VIBATc 100V+(SRP*SRN) GTRTotalAccuracyin%+IBATmIBATcVIBATm9.Refer to Table 1 to determine the logic operation of the bq24702 and the bq24703.www.ti.com9元器件交易网www.cecb2b.com10R140.025SYSTEMU3SI4435DYL133µHR200.025 ΩBattery PlusR21Note1C1122µFNote135 VD4MBRD0CTT4R19Note1VCC22C74.7µF35 VC8Note1R13100 ΩR15100 ΩC12Note135VR1810ΩD2BAS16C31µFU2SI4435DYD1MBRD0CTT4ACAdapterbq24702, bq24703R11R6100 kΩOpenR12Note124ACDRV11ACN12ACPPWM21SRP16SRN15COMP10D5Note 1D6Note 1R22604 kΩR24604 kΩC10180pFD99BATSET5SRSETBATDRV23VS18Connect to GNDto DisableR28Note16ACSETR8Note117GNDR10Note1R26100KR27604 kΩR23Note1BAS16R25Note1C4150pFR16100 ΩC54.7µF1ACDETR2930 kΩ14IBATR2100 kΩ7VREFC6D313 V1µF16VVHSP20SLUS553D − MAY 2003 − REVISED JULY 2005APPLICATION DIAGRAMIBATC131 nFC14.7µFENABLEbq24702bq247033ACSEL19ALARM2ACPRESBATP1348ENABLEBATDEPACSELwww.ti.comALARMACPRESBATSETU4SI4435DYPROCESSOR’SPOWER SUPPLYNote 1:R8 Sets AC Adapter Current LimitR10 Sets Charge CurrentR12 Sets AC ADAPTER Current LimitR23 Sets the Battery Depleted ThresholdR25 Sets the Charge Regulation VoltageR28 Sets System Break Before MakeR19 = R21, Sets Zero Volt Charge CurrentC11 Optional, See Application NotesC12 For Value, See Application NotesC8 Value Depends on R21 and R19, See Application NotesD5, D6 Refer to the Application Section元器件交易网www.cecb2b.comSLUS553D − MAY 2003 − REVISED JULY 2005bq24702, bq24703BLOCK DIAGRAMVHSP20VCC22VREFVHSPREGULATORACPRESHYSTACDET1+ACPRESVCCS2 VVACPRESOSC+VHSPRQQPWMLOGICLEVELSHIFTHIGH−SIDEDRIVE21PWMVOLTAGEREFERENCEVREF7ACPRES2300 kHzACSEL35 V100µABATTERYVOLTAGEERRORAMPLIFIER2 kΩVCC+acCURRENTERRORAMPLIFIERSRN2 kΩ+BATTERYCURRENTERRORAMPLIFIER0.8 x VNOBAT+NO BATTERYCOMPARATORDEPLETEDBATTERYCOMPARATORBATP+SWITCH TOBATTERYACPRESACSEL125kΩ+VFB+BATDAVTBDENABLE8+Zero VoltCharging1390.25 VBATPBATSETCOMPACPACNACSET1012116+5 V1615SRPSRNSRSET+5VCC25kΩVBATDEPBATDEP4+ADAPTERSELECTDRIVEVHSP24ACDRV2BATTERY SELECTLOGICANDANTI−CROSSCONDUCTACDRVVCCSRPSRN+A=20BATTERYSELECTDRIVEVCC2317BATDRVGNDVSALARM18191bq24702 ONLY2bq24703 ONLYACSEL14IBATUDG−00137www.ti.com11元器件交易网www.cecb2b.combq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005Terminal FunctionsTERMINALNAMEACDETACDRVACNACPACPRESACSELACSETALARMBATDEPBATDRVBATPBATSETCOMPENABLEGNDIBATPWMSRNSRPSRSETVCCVHSPVREFVSbq24702(PW)124111223619423139108171421151652220718bq24703(QFN)2625272831912412675171321151622220418I/OIOIIOIIOIOIIOIOOOII/OIIOOIAC or adapter power detectionAC or adapter power source selection outputNegative differential inputPositive differential inputAC power indicatorAC adapter power selectAdapter current programming voltageAlarm outputDepleted battery levelBattery power source select outputBattery charge regulation voltage measurement input to the battery-voltage gm amplifierExternal override to an internal precision referenceInverting input to the PWM comparatorCharge enableSupply return and ground referenceBattery current differential amplifier outputGate drive outputNegative differential battery current sense amplifier inputPositive differential battery current sense amplifier inputBattery charge current programming voltageOperational supply voltageVoltage source to drive gates of the external MOSFETsPrecision 5-V referenceSystem (load) voltage input pinDESCRIPTION12www.ti.com元器件交易网www.cecb2b.comSLUS553D − MAY 2003 − REVISED JULY 2005bq24702, bq24703Pin AssignmentsACDET: AC or adapter power detection. This input pin is used to determine the presence of the ac adapter.When the voltage level on the ACDET pin is less than VACPRES, the bq24702/bq24703 is in sleep mode, thePWM control is disabled, the BATDRV is driven low, and the ACDRV is driven high. This feature can be usedto automatically select battery as the system power source.ACDRV: AC or adapter power source select output. This pin drives an external P-channel MOSFET used toswitch to the ac wall-adapter as the system power source. When the ACSEL pin is high while the voltage onthe ACDET pin is greater than VACPRES, the output ACDRV pin is driven low (VHSP). This pin is driven high (VCC)when the ACDET is less than VACPRES.ACN, ACP: Negative and positive differential inputs, respectively for ac-to-dc adapter current sense resistor.ACPRES: This open-drain output pin is used to indicate the presence of ac power. A logic high indicates thereis a valid ac input. A low indicates the loss of ac power. ACPRES is high when the voltage level on the ACDETpin is greater than VACPRES.ACSEL: AC adapter power select. This input selects either the ac adapter or the battery as the power source.A logic high selects ac power, while a logic low selects the battery.ACSET: Adapter current programming voltage. This input sets the system current level at which dynamic powermanagement occurs. Adapter currents above this programmed level activate the dynamic power managementand proportionally reduce the available power to the battery.ALARM: Depleted battery alarm output. This open-drain pin indicates that a depleted battery condition exists.A pullup on ALARM goes high when the voltage on the BATDEP pin is below VACPRES. On the bq24702, theALARM output also activates when the selector inputs do not match the selector state.BATDEP: Depleted battery level. A voltage divider network from the battery to BATDEP pin is used to set thebattery voltage level at which depletion is indicated by the ALARM pin. See ALARM pin for more details. Abattery depletion is detected when BATDEP is less than VACPRES. A no-battery condition is detected when thebattery voltage is < 80% of the depleted threshold. In a no-battery condition, the bq24702 automatically selectsac as the input source. If ENABLE = 1, the PWM remains enabled.BATDRV: Battery power source select output. This pin drives an external P-channel MOSFET used to switchthe battery as the system’s power source. When the voltage level on the ACDET pin is less than VACPRES, theoutput of the BATDRV pin is driven low, GND. This pin is driven high (VCC) when ACSEL is high and ACDET> VACPRES.BATP: Battery charge regulation voltage measurement input to the battery-voltage gm amplifier. The voltageon this pin is typically derived from a voltage divider network connected across the battery. In a voltage loop,BATP is regulated to the VFB precision reference of the battery voltage gm amplifier.BATSET: An external override to an internal precision reference. When BATSET is > 0.25 V, the voltage levelon the BATSET pin sets the voltage charge level. When BATSET ≤ 0.25 V, an internal VFB reference isconnected to the inverting input of the battery error amplifier. To ensure proper battery voltage regulation withBATSET, BATSET must be > 1.0 V. Simply ground BATSET to use the internal reference.COMP: The inverting input to the PWM comparator and output of the gm amplifiers. A type II compensationnetwork between COMP and GND is recommended.ENABLE: Charge enable. A high on this input pin allows PWM control operation to enable charging while a lowon this pin disables and forces the PWM output to a high state. Battery charging is initiated by asserting a logic1 on the ENABLE pin.GND: Supply return and ground referenceIBAT: Battery current differential amplifier output. The output of this pin produces a voltage proportional to thebattery charge current. This voltage is suitable for driving an ADC input.www.ti.com13元器件交易网www.cecb2b.combq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005PWM: Gate drive output pin drives the P-channel MOSFET for PWM control. The PWM control is active whenACPRES, ACSEL, and ENABLE are high. PWM is driven low to VHSP and high to VCC.SRN, SRP: Differential amplifier inputs for battery current sense. These pins feed back the battery chargecurrent for PWM control. SRN is tied to the battery terminal. SRP is the source pin for zero volt operation.SRSET: Battery charge current programmed voltage. The level on this pin sets the battery charge current limit.VCC: Operational supply voltage.VHSP: The VHSP pin is connected to a 1-µF capacitor (close to the pin) to provide a stable voltage source todrive the gates of the external MOSFETs. VHSP = VCC − 10 V for VCC > 10.5 V and VHSP = VCC − 0.5 V forVCC <10.5 V. A 13-V Zener diode should be placed between VCC and VHSP to prevent MOSFET overstressduring start-up.VREF: Bypassed precision voltage 5-V output. It can be used to set fixed levels on the inverting inputs of anyone of the three error amplifiers if desired. The tight tolerance is suitable for charging lithium-ion batteries.VS: System (Load) voltage input pin. The voltage on this pin indicates the system voltage in order to insure abreak before make transition when changing from ac power to battery power. The battery is protected from anover-voltage condition by disabling the P-channel MOSFET connected to the BATDRV pin if the voltage at VSis greater than BATP. This function can be eliminated by grounding the VS pin.14www.ti.com元器件交易网www.cecb2b.comSLUS553D − MAY 2003 − REVISED JULY 2005bq24702, bq24703APPLICATION INFORMATIONProgramming the ThresholdsThe input-referenced thresholds for battery depleted, ac detection and charge voltage are defined bydimensioning the external dividers connected to pins BATDEP, ACDET and BATP. This calculation is simple,and consists of assuming that when the input voltage equals the desired threshold value the voltage at therelated pin is equal to the pin internal reference voltage:Vinput = Vpin × (1 + Kres)where:Vinput = Target threshold, referenced to input signalVpin = Internal reference(1.196 V for BATP; 1.246 V for BATDEP, ACDET)Kres = External resistive divider gain ( for instance: R24/R25 for BATP)When using external dividers with high absolute value the input bias currents for those pins must be includedin the threshold calculation. On the bq24702/3 the input bias currents increase the actual value for the thresholdvoltage, when compared to the values calculated using the internal references and divider gain only:Vinput = Vpin × (1+Kres) + VbiasThe increase on the threshold voltage is given by: Vbias = Rdiv × Ipinwhere:Vbias = Voltage increase due to pin bias currentRdiv = External resistor value for resistor connected from pin to input voltageIpin = Maximum pin leakage currentThe effect of IB can be reduced if the resistor values are decreased.Dynamic Power ManagementThe dynamic power management (DPM) feature allows a cost effective choice of an ac wall-adapter thataccommodates 90% of the system’s operating-current requirements. It minimizes battery charge time byallocating available power to charge the battery (i.e. IBAT = IADPT − ISYS). If the system plus battery chargecurrent exceeds the adapter current limit, as shown in Figure 1, the DPM feature reduces the battery chargecurrent to maintain an overall input current consumption within user defined power capability of the wall-adapter.As the system’s current requirements decrease, additional current can be directed to the battery, therebyincreasing battery charge current and minimizing battery charge time.The DPM feature is inherently designed into the PWM controller by inclusion of the three control loops,battery-charge regulation voltage, battery-charge current, and adapter-charge current, refer to Figure 2. If anyof the three user programmed limits are reached, the corresponding control loop commands the PWM controllerto reduce duty cycle, thereby reducing the battery charge current.www.ti.com15元器件交易网www.cecb2b.combq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005ADAPTER CURRENT LIMITADAPTER CURRENTSYSTEM CURRENTBATTERY CHARGE CURRENTNOCHARGEMAXIMUMCHARGE CURRENTDYNAMIC POWERMANAGEMENTMAXIMUMCHARGE CURRENTUDG−00113Figure 1. Dynamic Power ManagementACDET OperationThe ACDET function senses the loss of adequate adapter power. If the voltage on ACDET drops below theinternal VACPRES reference voltage, a loss of ADAPTER power is declared and the bq24702/bq24703 switchesto battery power as the main system power. In addition, the bq24702/bq24703 shuts down its 5-V VREF andenters a low power sleep mode.Battery Charger OperationThe bq24702/bq24703 fixed-frequency, PWM controller is designed to provide closed-loop control of batterycharge-current (ICH) based on three parameters, battery-float voltage (VBAT), battery-charge current, andadapter charge current (IADPT). The bq24702/bq24703 is designed primarily for control of a buck converterusing a high side P-channel MOSFET device (SW, refer to Figure 2).The three control parameters are voltage programmable through resistor dividers from the bq24702/bq24703precision 5-V reference, an external or internal precision reference, or directly via a DAC interface from akeyboard controller.Adapter and battery-charge current information is sensed and fed back to two transconductance (gm) amplifiersvia low-value-sense resistors in series with the adapter and battery respectively. Battery voltage information issensed through an external resistor divider and fed back from the battery to a third gm amplifier.Precharge OperationThe precharge operation must be performed using the PWM regulator. The host can set the precharge currentexternally by monitoring the ALARM pin to detect a battery depleted condition and programming SRSET voltageto obtain the desired precharge current level.16www.ti.com元器件交易网www.cecb2b.comSLUS553D − MAY 2003 − REVISED JULY 2005bq24702, bq24703Zero Volt OperatingThe zero volt operation is intended to provide a low current path to close open packs and protect the systemin the event of a pack cell short-circuit condition or if a short is applied to the pack terminal. It is not designedto precharge depleted packs, as it is disabled at voltages that are not within normal pack operating range forprecharge.If the voltage at BATDEP pin is below the zero volt operation threshold , charge is enabled (EN=HI), and ac isselected (ACSEL=HI) the bq24702/3 enters the zero volt operation mode. When the zero volt operation modeis on, the internal PWM is disabled, and an internal power MOSFET connects SRP to VCC. The battery chargecurrent is limited by the filter resistor connected to SRP pin (R19). R19 must be dimensioned to withstand theworst case power dissipation when in zero volt operation mode.The zero volt operation mode is disabled when BATDEP is above the zero volt operation threshold, and the mainPWM loop is turned on if charge is enabled, regulating the current to the value set by SRSET voltage. To avoiderrors on the charge current both resistors on the SRP, SRN filter must have the same value. Note, however,that R21 (connected to SRN) does not dissipate any power when in zero volt operation and can be of minimumsize.PWM OperationThe three open collector gm amplifiers are tied to the COMP pin (refer to Figure 2), which is internally biasedup by a 100-µA constant current source. The voltage on the COMP pin is the control voltage (VC) for the PWMcomparator. The PWM comparator compares VC to the sawtooth ramp of the internally fixed 300-kHz oscillatorto provide duty cycle information for the PWM drive. The PWM drive is level-shifted to provide adequate gatevoltage levels for the external P-channel MOSFET. Refer to PWM selector switch gate drive section for gatedrive voltage levels.+VADPTD1VBATISWQ1SWCLKOSCRAMP5 V100µACOMP10ENABLESRQQLATCH OUTLEVELSHIFTVCCPWMDRIVEVHSP21PWMPWM COMPARATORFROM ENABLE LOGIC+ZCOMPENABLEBATTERYVOLTAGEBATTERY CHARGECURRENTADP CURRENTgmAMPLIFIERS+1.25 V13BATPUDG−00114Figure 2. PWM Controller Block Diagramwww.ti.com17元器件交易网www.cecb2b.combq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005SoftstartSoftstart is provided to ensure an orderly start-up when the PWM is enabled. When the PWM controller isdisabled (ENABLE = Low), the 100-µA current source pullup is disabled and the COMP pin is actively pulleddown to GND. Disabling the 100-µA pullup reduces current drain when the PWM is disabled. When thebq24702/bq24703 PWM is enabled (ENABLE = High), the COMP pin is released and the 100-µA pullup isenabled (refer to Figure 2). The voltage on the COMP pin increases as the pullup charges the externalcompensation network connected to the COMP pin. As the voltage on the COMP pin increases the PWM dutycycle increases linearly as shown in Figure 3.PERCENT DUTY CYCLEvsCOMPENSATION VOLTAGE1009080Percent Duty Cycle − %7060504030201001.21.72.22.73.2VCOMP − Compensation Voltage − VFigure 3As any one of the three controlling loops approaches the programmed limit, the gm amplifier begins to shuntcurrent away from the COMP pin. The rate of voltage rise on the COMP pin slows due to the decrease in totalcurrent out of the pin, decreasing the rate of duty cycle increase. When the loop has reached the programmedlimit the gm amplifier shunts the entire bias current (100 µA) and the duty cycle remains fixed. If any of the controlparameters tries to exceed the programmed limit, the gm amplifier shunts additional current from the COMP pin,further reducing the PWM duty cycle until the offending parameter is brought into check.Setting the Battery Charge Regulation VoltageThe battery charge regulation voltage is programmed through the BATSET pin, if the internal precisionreference is not used. The BATSET input is a high-impedance input that is driven by either a keyboard controllerDAC or via a resistor divider from a precision reference (see Figure 4).The battery voltage is fed back to the gm amplifier through a resistor divider network. The battery chargeregulation voltage can be defined as:VBATTERY+(R1)R2) VR2BATSETV)IBATP R1(1)where IBATP = input bias current for pin BATP18www.ti.com元器件交易网www.cecb2b.comSLUS553D − MAY 2003 − REVISED JULY 2005bq24702, bq24703The overall accuracy of the battery charge regulation voltage is a function of the bypassed 5-V reference voltagetolerance as well as the tolerances on R1 and R2. The precision voltage reference has a 0.5% tolerance makingit suitable for the tight battery voltage requirements of Li-ion batteries. Tolerance resistors of 0.1% arerecommended for R1 and R2 as well as any resistors used to set BATSET.The bq24702/bq24703 provides the capability of using an internal precision voltage reference through the useof a multiplexing scheme, refer to Figure 4, on the BATSET pin. When BATSET voltage is less than 0.25 V, aninternal reference is switched in and the BATSET pin is switched out from the gm amplifier input. When theBATSET voltage is greater than 0.25 V, the BATSET pin voltage is switched in to the input of the gm amplifierand the voltage reference is switched out.NOTE:The minimum recommended BATSET is 1.0 V, if BATSET is used to set the voltage loop.VBATBATP13BATSETgm AMPLIFIER+910COMP0.25 VVBAT1.25 V(a) VBATSET < 0.25 VR1VREF = 5 VBATP13R2gm AMPLIFIER+10COMP9BATSET0.25 V1.196 V(b) VBATSET > 1 VUDG−00116Figure 4. Battery Error Amplifier Input Multiplexing Schemewww.ti.com19元器件交易网www.cecb2b.combq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005Programming the Battery Charge CurrentThe battery charge current is programmed via a voltage on the SRSET pin. This voltage can be derived froma resistor divider from the 5-V VREF or by means of an DAC. The voltage is converted to a current source thatis used to develop a voltage drop across an internal offset resistor at one input of the SR gm amplifier. The chargecurrent is then a function of this voltage drop and the sense resistor (RS), refer to Figure 5.RSCOMP10VREF+2 kΩ16SRPSRN15SRSET5+25 kΩUDG−00117Figure 5. Battery Charge Current Input Threshold FunctionThe battery charge current can be defined as:I+SRSETBAT25 RSV(2)where VSRSET is the programming voltage on the SRSET pin. VSRSET maximum is 2.5 V.Programming the Adapter CurrentLike the battery charge current described previously, the adapter current is programmed via a voltage on theACSET pin. That voltage can either be from an external resistor divider from the 5-V VREF or from an externalDAC. The adapter current is defined as:IADPT+ACSET25 RS2V(3)20www.ti.com元器件交易网www.cecb2b.comSLUS553D − MAY 2003 − REVISED JULY 2005bq24702, bq24703COMPONENT SELECTIONMOSFET SelectionMOSFET selection depends on several factors, namely, gate-source voltage, input voltage, and input current.The MOSFET must be a P-channel device capable of handling at least 15-V gate-to-source with a drain-sourcebreakdown of VBV~ VIN+1 V. The average input current can be approximated by:I(avg)+D IchgIND = Duty cycleIchg = Charge current(4)The RMS current through the MOSFET is defined as:I(RMS)+Ichg ǸDAINRMS(5)AThe rise/fall times for pin PWM for the selected MOSFET should be greater than 40 nsec.Schottky Rectifier (Freewheeling)The freewheeling Schottky rectifier must also be selected to withstand the input voltage, VIN. The averagecurrent can be approximated from:I(avg)+Ichg (1*D)AD1(6)Choosing an InductanceLow inductance values result in a steep current ramp or slope. Steeper current slopes result in the converteroperating in the discontinuous mode at a higher power level. Steeper current slopes also result in higher outputripple current, which may require a higher number or more expensive capacitors to filter the higher ripple current.In addition, the higher ripple current results in an error in the sensed battery current particularly at lower chargingcurrents. It is recommended that the ripple current not exceed 20% to 30% of full scale dc current.*VINBATL+F Ichg RippleSRipple = % Ripple allowed (Ex.: 0,2 for 20% ripple)D V(7)Too large an inductor value results in the current waveform of Q1 and D1 in Figure 2 approximating asquarewave with an almost flat current slope on the step. In this case, the inductor is usually much larger thannecessary, which may result in an efficiency loss (higher DCR) and an area penalty.Selecting an Output CapacitorFor this application the output capacitor is used primarily to shunt the output ripple current away from the battery.The output capacitor should be sized to handle the full output ripple current as defined as:Ic(RMS)+ǒǓǒVIN*VBATǓ DF LSARMS(8)www.ti.com21元器件交易网www.cecb2b.combq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005Selecting an Input CapacitorThe input capacitor is used to shunt the converter ripple current on the input lines. The capacitor(s) must havea ripple current (RMS) rating of:IRMS+Ǹ[Ichg (1–D)]2 D)[Ichg D]2 (1–D)ARMS(9)In addition to shunting the converter input ripple when the PWM is operating, the input capacitor also acts aspart of an LC filter, where the inductance component is defined by the ac adapter cable inductance and boardtrace inductance from adapter connector to filter capacitor. Overshoot conditions can be observed at VCC lineduring fast load transients when the adapter powers the load or when the adapter is hot-plugged .Increasing the input capacitor value decreases the overshoot at VCC. Avoid overshoot voltages at VCC in excessof the absolute maximum ratings for that pin.Compensating the LoopFor the bq24702/bq24703 used as a buck converter, the best method of compensation is to use a Type IIcompensation network from the output of the transconductance amplifiers (COMP pin) to ground (GND) asshown in Figure 2. A Type II compensation adds a pole-zero pair and an additional pole at dc.The Type II compensation network places a zero atF+1 Z2and a pole atF+1 P2ǒp R1COMP CZǓǓHz(10)ǒp R1COMP CPHz(11)For this battery charger application the following component values: CZ = 4.7 µF, CP = 150 pF, andRCOMP = 100 Ω, provides a closed loop response with more than sufficient phase margin, as long as the LCpole [1/2 ×PI ×sqrt (l×c)] is set below 10 kHz. The SRP/SRN filter (R19, R21, C8) and ACP/ACN filter(R13/R15/C3) are required to filter noise associated with the PWM switching. To avoid adding secondary polesto the PWM closed loop system those filters should be set with cutoff frequencies higher than 1 kHz.Selector OperationThe bq24702/bq24703 allows the host controller to manually select the battery as the system’s main powersource, without having to remove adapter power. This allows battery conditioning through smart battery learncycles. In addition, the bq24702/bq24703 supports autonomous supply selection during fault conditions oneither supply. The selector function uses low RDS(on) P-channel MOSFETs for reduced voltage drops and longerbattery run times.NOTE: Selection of battery power whether manual or automatic results in the suspension of batterycharging.22www.ti.com元器件交易网www.cecb2b.comSLUS553D − MAY 2003 − REVISED JULY 2005bq24702, bq24703ADAPTER SELECT SWITCHADAPTERINPUT(bq24702)PWMBATTERYCHARGERACDRV(bq24702)24BATTERYSELECTORBATDRVCONTROL23BATSYSTEMLOADBATTERYSELECTSWITCHUDG−00119Figure 6. Selector Control SwitchesAutonomous Selection OperationAdapter voltage information is sensed at the ACDET pin via a resistor divider from the adapter input. The voltageon the ACDET pin is compared to an internally fixed threshold. An ACDET voltage less than the set thresholdis considered as a loss of adapter power regardless of the actual voltage at the adapter input. Informationconcerning the status of adapter power is fed back to the host controller through ACPRES. The presence ofadapter power is indicated by ACPRES being set high. A loss of adapter power is indicated by ACPRES goinglow regardless of which power source is powering the system. During a loss of adapter power, thebq24702/bq24703 obtains operating power from the battery through the body diode of the P-channel batteryselect MOSFET. Under a loss of adapter power, ACPRES (normally high) goes low, if adapter power is selectedto power the system, the bq24702/bq24703 automatically switches over to battery power by commandingACDRV high and BATDRV low. During the switch transition period, battery power is supplied to the load via thebody diode of the battery select P-channel MOSFET. When adapter power is restored, the bq24702/bq24703configures the selector switches according to the state of signals; ACSEL, and ACPRES. If the ACSEL pin isleft high when ac power is restored, the bq24702/bq24703 automatically switches back to ac power. To remainon battery power after ac power is restored, the ACSEL pin must be brought low.Conversely, if the battery is removed while the system is running on battery power and adapter power is present,the bq24702/bq24703 automatically switches over to adapter power by commanding BATDRV high andACDRV low.NOTE: For the bq24702 any fault condition that results in the selector MOSFET switches notmatching their programmed states is indicated by the ALARM pin momentarily going high. Referto Battery Depletion Detection Section for more information on the ALARM discrete.When switching between the ac adapter and battery the internal logic monitors the voltage at pins ACDRV andBATDRV to implement a break-before-make function, with typical dead time on the order of 150 nsec.The turnon times for the external ac/battery switches can be increased to minimize inrush peak currents; thatcan be accomplished by adding external resistors in series with the MOSFET gates(R18 and R26). Note,however, that adding those resistors effectively disables the internal break-before-make function forac/battery-switches, as the MOSFET gate voltages can not be monitored directly. If external resistors are addedto increase the rise/fall times for battery/ac switches the break-before-make has to be implemented with discreteexternal components, to avoid shoot-through currents between ac adapter and battery pack. This functionalitycan be implemented by adding diodes (D2/D9) that bypass the external resistors when turning off the externalFETs.www.ti.com23元器件交易网www.cecb2b.combq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005Smart Learn Cycles When Adapter Power Is PresentSmart learn cycles can be conducted when adapter power is present by asserting and maintaining the ACSELpin low. The adapter power can be reselected at the end of the learn cycle by a setting ACSEL to a logic high,provided that adapter power is present. Battery charging is suspended while selected as the system powersource.NOTE: On the bq24703 the ac adapter is switched to the load when the battery voltage reachesthe battery depleted threshold; it can be used when the learn cycle does not require the batteryvoltage to go below the battery depleted threshold. If the learn cycle algorithm requires the batteryvoltage to go lower than the battery depleted voltage, the bq24702 should be used, as it does notswitch the ac adapter to load upon battery depleted detection.System Break Before Make FunctionWhen selecting the battery as the system primary power source, the adapter power select MOSFET turns off,in a break-before-make fashion, before the battery select MOSFET turns on. To ensure that this happens underall load conditions, the system voltage (load voltage) can be monitored through a resistor divider on the VS pin.This function provides protection against switching over to battery power if the adapter selector switch wereshorted and adapter power present. Setting the VS resistive divider gain with the same gain selected for theBATP resistive divider assures the battery switch is turned on only when the system voltage is equal or less thanthe battery voltage. This function can be eliminated by grounding the VS pin.The ACDET function senses the adapter voltage via a resistive divider (refer to application circuit).The dividercan be connected either to the anode of the input blocking diode (directly to the adapter supply) or to the cathodeof the input blocking diode (bq24702/3 VCC pin). When the divider is connected to the adapter supply, theadapter power removal is immediately identified and the sleep mode is entered, disabling thebreak-before-make function for system voltage (see section for system power switching) and coupling systemvoltage to the battery line. In normal operation with a battery present, the battery low impedance prevents anyover-voltage conditions. However, if a pack is not present or the pack is open, the battery line voltage has atransient equal to the adapter voltage. The bq24703 SRP/SRN pins are designed to withstand this over-voltagecondition, but avoid connection to the battery line of any external devices that are not rated to withstand theadapter voltage.Connecting the ACDET resistive divider input to the VCC node keeps the system break-before-make functionenabled until the voltage at pin VS is lower than the voltage at pin BATP. However, note that when using thistopology the VCC pin voltage can be held by capacitive loads at either the VCC or system (ac switch is on) nodeswhen the ac adapter is removed. As the ACDET divider is connected to the VCC line there is a time delay fromac adapter removal to ac adapter removal detection by the IC. This time is dependent on load conditions andcapacitive load values at VCC and system lines.Battery Depletion DetectionThe bq24702/bq24703 provides the host controller with a battery depletion discrete, the ALARM pin, to alertthe host when a depleted battery condition occurs. The battery depletion level is set by the voltage applied tothe BATDEP pin through a voltage divider network. The ALARM output asserts high and remains high as longas the battery deplete condition exists, regardless of the power source selected.For the bq24702, the host controller must take appropriate action during a battery deplete condition to selectthe proper power source. The bq24702 remains on the selected power source. The bq24703, however,automatically reverts over to adapter power, provided the adapter is present, during a deep discharge state. Thebattery is considered as being in a deep discharge state when the battery voltage is less than (0.8× depletedlevel).Feature sets for the bq24702 and bq24703 are detailed in Table 1.24www.ti.com元器件交易网www.cecb2b.comSLUS553D − MAY 2003 − REVISED JULY 2005bq24702, bq24703SELECTOR/ALARM TIMING EXAMPLEThe selector and ALARM timing example in Figure 7 illustrates the battery conditioning support.NOTE: For manual selection of wall power as the main power source, both the ACPRES andACSEL signals must be a logic high.ACPRESACSELACDRVBATDRVALARMbq24703 ONLYBATTERYDEPLETECONDITIONUDG−00122ACSEL(ACPRES)tBATSELACDRVBATDRVtACSELBATDEP< 1 VtACSELBATDRVACDRVtBATSELUDG−00120Figure 7. Battery Selector and ALARM Timing Diagramwww.ti.com25元器件交易网www.cecb2b.combq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005PWM SELECTOR SWITCH GATE DRIVEBecause the external P-channel MOSFETs (as well as the internal MOSFETs) have a maximum gate-sourcevoltage limitation of the input voltage, VCC, cannot be used directly to drive the MOSFET gate under all inputconditions. To provide safe MOSFET-gate-drive at input voltages of less than an intermediate gate drive voltagerail was established (VSHP). Where VHSP = VCC − 10 V. This ensures adequate enhancement voltage acrossall operating conditions.An external zener diode (D3) connected between VCC and VHSP is required for transient protection; itsbreakdown voltage should be above the maximum value for internal VHSP/VCC clamp voltage for all operatingconditions.TRANSIENT CONDITIONS AT SYSTEM, OVER-VOLTAGE AT SYSTEM TERMINALOvershoot conditions can be observed at the system terminal due to fast load transients and inductivecharacteristics of the system terminal to load connection. An overshoot at the system terminal can be directlycoupled to the VCC and VBAT nodes, depending on the switch mode of operation. If the capacitors at VBATand VCC can not reduce this overshoot to values below the absolute maximum ratings, it is recommended thatan additional capacitor is added to the system terminal to avoid damage to IC or external components due tovoltage overstress under those transient conditions.AC ADAPTER COLLAPSING DUE TO TRANSIENT CONDITIONSThe ac adapter voltage collapses when the ac switch is on and a current load transient at the system exceedsthe adapter current limit protection. Under those conditions the ac switch is turned off when the ac adaptervoltage falls below the ac adapter detection threshold. If the system terminal to load impedance has an inductivecharacteristic, a negative voltage spike can be generated at the system terminal and coupled into the batteryline via the battery switch backgate diode.In normal operation, with a battery present, this is not an issue, as the low battery impedance holds the voltageat battery line. However, if a battery is not present or the pack protector switches are open the negative spikeat the system terminal is directly coupled to the SRP/SRN pins via the R19/R21 resistors.Avoid damage to the SRP/SRN pins if this transient condition happens in the application. If a negative voltagespike happens at system terminal and R19/R21 limit the current sourced from the pin to less than −50 mA (Ipin= Vsystem/R19), the pins SRP/SRN are not damaged and the external protection schottky diodes are notrequired. However, if the current under those transient conditions exceeds −50mA, external schottky diodesmust be added to clamp the voltage at pins SRP/SRN so they do not exceed the absolute maximum ratingsspecified (−0.3 V).IBAT AMPLIFIERA filter with a cutoff frequency smaller than 10kHz should be added to the IBAT output to remove switchingnoise.POWER DISSIPATION CALCULATIONDuring PWM operation, the power dissipated internally to the IC increases as the internal driver is switching thePWM FET on/off. The power dissipation figures are dependent on the external FET used, and can be calculatedusing the following equation:Pd(max) = [IDDOP + Qg × Fs(max)] × VADAPwhere:Qg= Total gate charge for selected PWM MOSFETIDDOP = Maximum quiescent current for ICVADAP = Maximum adapter voltageFs(max) = Maximum PWM switching frequencyThe maximum junction temperature for the IC must be limited to 125°C, under worst case conditions.26www.ti.com元器件交易网www.cecb2b.comSLUS553D − MAY 2003 − REVISED JULY 2005bq24702, bq24703TYPICAL CHARACTERISTICSERROR AMPLIFIER REFERENCEvsJUNCTION TEMPERATURE1.215VCC = 18 VVFB−Error Amplifier Reference − V1.211.2051.21.1951.191.1851.181.175−40VREF − 5 -V Reference − V5.15.085.065.045.0254.984.9.944.921060TJ − Junction Temperature − _C1101254.9−401060110125TJ − Junction Temperature − _CVCC = 18 VBYPASSED 5-V REFERENCEvsJUNCTION TEMPERATUREFigure 8TOTAL SLEEP CURRENTvsJUNCTION TEMPERATURE26VCC = 18 VISLEEP− Battery Sleep Current − µAf − Oscillator Frequency − kHz2433532531530529528527526525524514−401060TJ − Junction Temperature − _C110125235−40VCC = 18 VFigure 9OSCILLATOR FREQUENCYvsJUNCTION TEMPERATURE222018161060110125TJ − Junction Temperature − _CFigure 10Figure 11www.ti.com27元器件交易网www.cecb2b.combq24702, bq24703SLUS553D − MAY 2003 − REVISED JULY 2005BATTERY CURRENT SET ACCURACYvsBATTERY CURRENT SET VOLTAGE25SRSET Full Scale = 2.5 V = Max Programmed CurrentTJ = 25°CAC Current Set Accuracy − %25AC CURRENT SET ACCURACYvsAC CURRENT SET VOLTAGEACSET Full Scale = 2.5 V= Max Programmed CurrentTJ = 25°CBattery Current Set Accuracy − %20201515101055011.251.51.7522.252.50.250.50.75VSRSET − Battery Current Set Voltage − V00.250.511.251.51.7522.252.5VACSET − AC Current Set Voltage − V0.75Figure 12Figure 13BOARD LAYOUT GUIDELINESRecommended Board LayoutFollow these guidelines when implementing the board layout:1.Do not place lines and components dedicated to battery/adapter voltage sensing (ACDET,BATDEP, VS),voltage feedback loop (BATP, BATSET if external reference is used) and shunt voltage sensing(SRP/SRN/ACP/ACN) close to lines that have signals with high dv/dt (PWM, BATDRV, ACDRV, VHSP) toavoid noise coupling.2.Add filter capacitors for SRP/SRN (C8) and ACP/ACN (C3) close to IC pins3.Add Reference filter capacitor C1 close to IC pins4.Use an isolated, clean ground for IC ground pin and resistive dividers used in voltage sensing; use anisolated power ground for PWM filter cap and diode (C11/D4). Connect the grounds to the battery PACK−and adapter GND.5.Place C7 close to VCC pin.6.Place input capacitor C12 close to PWM switch (U3) source and R14.7.Position ac switch (U2) to minimize trace length from ac switch source to input capacitor C12.8.Minimize inductance of trace connecting PWM pin and PWM external switch U3 gate9.Maximize power dissipation planes connected to PWM switch10.Maximize power dissipation planes connected to SRP resistor if steady state in zero volt mode is possible11.Maximize power dissipation planes connected to D128www.ti.com元器件交易网www.cecb2b.com

PACKAGEOPTIONADDENDUM

www.ti.com

27-Sep-2005

PACKAGINGINFORMATION

OrderableDeviceBQ24702PWBQ24702PWG4BQ24702PWRBQ24702PWRG4BQ24703PWBQ24703PWRBQ24703PWRG4BQ24703RHDRBQ24703RHDRG4

(1)

Status(1)ACTIVEACTIVEACTIVEACTIVEACTIVEACTIVEACTIVEACTIVEACTIVE

PackageTypeTSSOPTSSOPTSSOPTSSOPTSSOPTSSOPTSSOPQFNQFN

PackageDrawingPWPWPWPWPWPWPWRHDRHD

PinsPackageEcoPlan(2)

Qty242424242424242828

6060

Green(RoHS&noSb/Br)Green(RoHS&noSb/Br)

Lead/BallFinishCUNIPDAUCUNIPDAUCUNIPDAUCUNIPDAUCUNIPDAUCUNIPDAUCUNIPDAUCUNIPDAUCUNIPDAU

MSLPeakTemp(3)Level-1-260C-UNLIMLevel-1-260C-UNLIMLevel-1-260C-UNLIMLevel-1-260C-UNLIMLevel-1-260C-UNLIMLevel-1-260C-UNLIMLevel-1-260C-UNLIMLevel-2-260C-1YEARLevel-2-260C-1YEAR

2000Green(RoHS&

noSb/Br)2000Green(RoHS&

noSb/Br)60

Green(RoHS&noSb/Br)

2000Green(RoHS&

noSb/Br)2000Green(RoHS&

noSb/Br)3000Green(RoHS&

noSb/Br)

Themarketingstatusvaluesaredefinedasfollows:ACTIVE:Productdevicerecommendedfornewdesigns.

LIFEBUY:TIhasannouncedthatthedevicewillbediscontinued,andalifetime-buyperiodisineffect.

NRND:Notrecommendedfornewdesigns.Deviceisinproductiontosupportexistingcustomers,butTIdoesnotrecommendusingthispartinanewdesign.

PREVIEW:Devicehasbeenannouncedbutisnotinproduction.Samplesmayormaynotbeavailable.OBSOLETE:TIhasdiscontinuedtheproductionofthedevice.

(2)

EcoPlan-Theplannedeco-friendlyclassification:Pb-Free(RoHS)orGreen(RoHS&noSb/Br)-pleasecheckhttp://www.ti.com/productcontentforthelatestavailabilityinformationandadditionalproductcontentdetails.TBD:ThePb-Free/Greenconversionplanhasnotbeendefined.

Pb-Free(RoHS):TI'sterms\"Lead-Free\"or\"Pb-Free\"meansemiconductorproductsthatarecompatiblewiththecurrentRoHSrequirementsforall6substances,includingtherequirementthatleadnotexceed0.1%byweightinhomogeneousmaterials.Wheredesignedtobesolderedathightemperatures,TIPb-Freeproductsaresuitableforuseinspecifiedlead-freeprocesses.

Green(RoHS&noSb/Br):TIdefines\"Green\"tomeanPb-Free(RoHScompatible),andfreeofBromine(Br)andAntimony(Sb)basedflameretardants(BrorSbdonotexceed0.1%byweightinhomogeneousmaterial)

(3)

MSL,PeakTemp.--TheMoistureSensitivityLevelratingaccordingtotheJEDECindustrystandardclassifications,andpeaksoldertemperature.

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Addendum-Page1

元器件交易网www.cecb2b.com

元器件交易网www.cecb2b.com MTSS001C – JANUARY 1995 – REVISED FEBRUARY 1999 MECHANICAL DATA PW (R-PDSO-G**) 14 PINS SHOWNPLASTIC SMALL-OUTLINE PACKAGE0,651480,300,190,10M0,15 NOM4,504,306,606,20Gage Plane0,251A70°–8°0,750,50Seating Plane1,20 MAX0,150,050,10PINS **DIMA MAX83,10145,10165,10206,60247,902,80A MIN2,904,904,906,407,709,6040400/F 01/97NOTES:A.B.C.D.All linear dimensions are in millimeters.This drawing is subject to change without notice.Body dimensions do not include mold flash or protrusion not to exceed 0,15.Falls within JEDEC MO-153POST OFFICE BOX 655303 DALLAS, TEXAS 75265•元器件交易网www.cecb2b.com

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