5 Optional section divider or presentation title slide High voltage charger block diagram5
6 8-cell Li-ion battery charger Basic requirements: Output: if 4.2V/cell battery, the output voltage setting needs 4.2Vx8=33.6V. Input: Vin > 33.6V+few volt hysteresisA typical bq24610/30 application circuit can not accept the input voltage higher than 32V (Input OVP setting).
7 Modified Charger Block Diagram The charger circuit have to do several modifications.The block diagram of HPA603 EVM:DC InputVcc BiasSupplyTPS540608~14V Vcc35~57VACNACPBATDRVREGNBTSTHIDRVPHLODRVGNDSRPSRNVFBVCCPre-chargeDeeply dischargedBatteryACDRVCEBTSTsettingCEVREFISET1ISET2ACSETTSTTCSTAT1STAT2PGVccQ1PackThermistorHalf BridgeGateDriveUCC27201LRsnsBattery PackQ2CurrentSenseINA169CVccBufferLM358VREFRs2~3VClampbq24610/30
8 VCC bias supply solution Function block: Vcc Bias supplyIt powers the charger IC-bq24610/30, external half bridge gate driver, current sense circuit and OMAMP buffer. And it is also used for charging up a deeply discharged battery. A switching Vcc bias power supply needs:Operating from the maximum input voltageAn 8-14 V output voltage: It is set by the external half bridge gate driver requirementAt least 200mA: It is derived from the sum of the charging current for deeply discharged battery and the whole board current consumption.For 60V input, the TPS54060 is selected to meet these three requirements.
10 Half bridge gate drive solution Function block: Half Bridge Gate DriveIt receives the charger IC HIDRV and LODRV signal and drive the buck FET Q5 and Q6. The half bridge gate drive needs:20% input voltage marginHave two Complementary inputs to match HIDRV and LODRV output of bq24610.Input logic high threshold need lower than 3V match the voltage level of bq24610/30’s HIDRV and LODRV output.Reserve several resistors, caps and diode to adjust turn-on&off speed and dead timeFor 60V input, the UCC27201 is selected to meet these three requirements.bq24610R13D3VccCinHIDRVPHLODRVPGNDHIVDDHBR25HOQ1C21UCC27201UCC27201HSC22LIVSSLOQ2R26R14D4
11 Modified Charger Block Diagram Current sense solutionBattery PackBATDRVREGNBTSTHIDRVPHLODRVGNDSRPSRNVFBVREFISET1ISET2ACSETTSTTCSTAT1STAT2PGQ2VCCQ1DC InputPackThermistorVccHalf BridgeGateDriveUCC27201Vcc BiasSupplyTPS54060bq24610/308~14V VccCurrentSenseINA1692~3VClampBufferLM358RsnsLCRsPre-chargeDeeply dischargedBatterysetting35~57VACNACPACDRVCE
12 Current sense solution Function block: Current senseIt is a high voltage bus current sensor or a current mirror circuit. It needsSet 1:1 ratio between Rsns Voltage and Rs voltage.For battery voltage is upto 60V, the INA169 is selected to meet that requirement.RsnsCurrent sense1kRs(R6)1k
14 Current sense buffer solution Function block: BufferThe SRP/SRN pin of charge IC has few milliampere sink current. The current sense output may not have enough current capability. The buffer circuit needs:Keep the output voltage on SRP/SRN pin is same as Rs voltageProvides enough current (8mA) to drive SRP/SRN pin.The LM358 is selected to meet these two requirements.LRsnsU1bq24610BufferU5:LM358CurrentsenseRs(R6)SRPR3SRN
16 2~3V clamp circuit solution Function block: 2~3v Clamp circuitIf the SRP/SRN pin voltage is lower than 2V, the IC runs at a short protection mode. The low side MOSFET is held off at that mode. The clamp circuit needs:Voltage is between 2~3V.Can absorb the Rs currentCan support SRN pin sink current (8mA)A simple 2~3V clamp circuit can be created from the bq24610’s 3.3V VREF.LRsnsCurrentsenseRs(R6)bq24610SRNVREFR27C30VREF
18 BTST setting Function block: BTST setting To isolate PH, HIDRV and BTST pin. The PH pin is connected to ground. BTST voltage needs:Higher than 3V to keep correct gate logic.Lower than 4V to keep LODRV send refresh pulse every switching cycle. External half bridge gate will use that LODRV refresh pulse to charge its bootstrap cap.A simply resistor divider from 6V REGN can set the BTST voltage easily.bq24610R22R21C16REGNBTST
20 Pre-condition deeply discharge battery solution Function block: Pre-condition deeply discharge batteryWhen battery voltage is deeply discharged lower than 3V, the current sense circuit can not work properly. The pre-condition circuit needs:The pre-condition current can bring a deeply discharged battery voltage higher than 3V.The pre-condition current is lower than bias supply output capability.A simply resistor (R46 and R47) and diode (D8) pre-charge path can pre-charge the battery voltage up to the 3V that is a minimum operating voltage range of the current sense circuit. A comparator compares the battery voltage with 3.3Vref. If the battery voltage is higher than 3.3V, the CE is pulled to high and charger is enabled.TPS54060VCC bias supplyD8R31R46R47VREFBATR10D7CELM2903
21 The calculation tool of L, C value and other parameters The calculation tool of L, C value and other parameters can be found inBattery charge voltage settingBattery pre-charge/termination current settingBattery fast-charge current settingIripple_Lout_VrippleLC output filter resonant frequencyFast charge timerTS resistor network
22 EVM and Application note information The high voltage charge EVM (HPA603) and user’s guide (SLUU447) are available.Application notes (SLUA580) is released: A practical high voltage charger solution with existing bq24610 charger IC.
24 Test result on HPA603 EVM 1 ISET1 control IBAT 2 Switching waveforms 1.1 ISET1 vs IBAT waveform1.2 ISET1 transient1.3 ISET1 accuracy2 Switching waveforms3 Charger start-up or shut-down with CE control4 Battery insertion and removal5 soft start6 efficiency
25 Modified Charger Block Diagram The charger circuit have to do several modifications.The block diagram of HPA603 EVM:DC InputVcc BiasSupplyTPS540608~14V Vcc35~57VACNACPBATDRVREGNBTSTHIDRVPHLODRVGNDSRPSRNVFBVCCPre-chargeDeeply dischargedBatteryACDRVCEBTSTsettingCEVREFISET1ISET2ACSETTSTTCSTAT1STAT2PGVccQ1PackThermistorHalf BridgeGateDriveUCC27201LRsnsBattery PackQ2CurrentSenseINA169CVccBufferLM358VREFRs2~3VClampbq24610/30
26 1.1 ISET1 vs IBAT waveformIBATISET1IBAT are proportional to ISET1. The ratio follows the datasheet equation.
27 1.2 ISET1 transient 2ISET1 from 1V to 2V （CCM）IBATISET1
34 More Higher input voltage charger: 100Vin_max and 16-cell 34
35 Higher input range solution If need a even high voltage, for example: 16 cell battery charger with 80V input.Please update those components and circuits:Changer requirementOutputInputbq24610EVM(HPA603EVM)8-cell Li-ion battery8x4.2=33.6VMaximum 60V input80Vin/16cellLi-ion battery Charger16-cell Li-ion battery16x4.2=67.2VMaximum 100V inputChange list:VCC bias supplyCurrent sense circuitR23(Vbatsetting)L1 value(Keep ΔIconstant)Power FETbq24610EVM(HPA603EVM)TPS54060INA169R23:464k22uH80V FET Si785280Vin/16cellLi-ion battery ChargerAny 100V input; bias supplyCurrent mirror:ZDS1009953k47uH100V FET SiR846