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Explore a high voltage charger block diagram, application circuits, and solutions for higher input voltage. Learn about a modified charger block diagram with enhanced features for Li-ion battery charging. Discover the importance of Vcc Bias Supply, Half Bridge Gate Drive, Current Sense, and Buffer circuits in high voltage charging applications.
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High voltage charger solution Li, Wang: wang-li@ti.com MGambrill, Michael: mgambrill@ti.com Liang, Roger: r-liang@ti.com
Abstract A typical bq24610 Application A high voltage charger block diagram Test results More higher input voltage solution SMBus high voltage charger solution
Power Source Selector A Typical standalone charger application circuit Q1 SYSTEM LOAD RAC: 10m Q2 R16 2Ω C3 10µF C2 10µF Adapter 10 C11 0.1µF C1 2.2µF ACN ACP ACDRV VREF CE ISET1 ISET2 ACSET TS TTC STAT1 STAT2 PG VCC BATDRV REGN BTST HIDRV PH LODRV GND SRP SRN VFB C7 0.1uF bq24610 Q3 C12 1µF C5:1µF R9 9.31kΩ R7 100kΩ R3 100kΩ R5 100kΩ C4 10uF Q4 Pack Thermistor RSR 10m L: 6.8µH Battery Pack R10 430kΩ R8 57.6kΩ R4 95.3kΩ R6 22.1kΩ C17 0.22µF Q5 C8 10µF C7 10µF Adapter C9 100pF R11:10kΩ R1 953kΩ C10 0.1µF R12:10kΩ R2 105kΩ R13:10kΩ bq24610: 600kHz, Li-Ion 4x4mm QFN-24 Typical 1-6 Li-Ion Cells, VIN max: 28V
Optional section divider or presentation title slide High voltage charger block diagram 5
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 hysteresis A typical bq24610/30 application circuit can not accept the input voltage higher than 32V (Input OVP setting).
Modified Charger Block Diagram The charger circuit have to do several modifications. The block diagram of HPA603 EVM: 8~14V Vcc Vcc Bias Supply TPS54060 DC Input 35~57V ACN ACP VCC Pre-charge Deeply discharged Battery BATDRV REGN BTST HIDRV PH LODRV GND SRP SRN VFB ACDRV BTST setting CE CE VREF ISET1 ISET2 ACSET TS TTC STAT1 STAT2 PG Vcc Q1 Half Bridge Gate Drive UCC27201 L Pack Thermistor Battery Pack Rsns Q2 Current Sense INA169 C Vcc Buffer LM358 VREF Rs 2~3V Clamp bq24610/30
VCC bias supply solution • Function block: Vcc Bias supply • It 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 voltage • An 8-14 V output voltage: It is set by the external half bridge gate driver requirement • At 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.
Modified Charger Block Diagram 8~14V Vcc Vcc Bias Supply TPS54060 DC Input 35~57V ACN ACP VCC Pre-charge Deeply discharged Battery BATDRV REGN BTST HIDRV PH LODRV GND SRP SRN VFB ACDRV BTST setting CE CE VREF ISET1 ISET2 ACSET TS TTC STAT1 STAT2 PG Vcc Q1 Half Bridge Gate Drive UCC27201 L Pack Thermistor Battery Pack Rsns Q2 Current Sense INA169 C Vcc Buffer LM358 VREF Rs 2~3V Clamp bq24610/30 Half bridge gate drive solution
Half bridge gate drive solution • Function block: Half Bridge Gate Drive • It 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 margin • Have 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 time • For 60V input, the UCC27201 is selected to meet these three requirements. Cin R13 D3 Vcc bq24610 HIDRV PH LODRV PGND R25 HB VDD HI Q1 HO UCC 27201 UCC 27201 C21 HS C22 LI Q2 LO VSS R26 R14 D4
Modified Charger Block Diagram 8~14V Vcc Vcc Bias Supply TPS54060 DC Input 35~57V ACN ACP VCC Pre-charge Deeply discharged Battery BATDRV REGN BTST HIDRV PH LODRV GND SRP SRN VFB ACDRV BTST setting CE CE VREF ISET1 ISET2 ACSET TS TTC STAT1 STAT2 PG Vcc Q1 Half Bridge Gate Drive UCC27201 L Pack Thermistor Battery Pack Rsns Q2 Current Sense INA169 C Vcc Buffer LM358 VREF Rs 2~3V Clamp bq24610/30 Current sense solution
Current sense solution • Function block: Current sense • It is a high voltage bus current sensor or a current mirror circuit. It needs • Set 1:1 ratio between Rsns Voltage and Rs voltage. • For batteryvoltage is upto 60V, the INA169 is selected to meet that requirement. Rsns Current sense 1k Rs (R6) 1k
Modified Charger Block Diagram 8~14V Vcc Vcc Bias Supply TPS54060 DC Input 35~57V ACN ACP VCC Pre-charge Deeply discharged Battery BATDRV REGN BTST HIDRV PH LODRV GND SRP SRN VFB ACDRV BTST setting CE CE VREF ISET1 ISET2 ACSET TS TTC STAT1 STAT2 PG Vcc Q1 Half Bridge Gate Drive UCC27201 L Pack Thermistor Battery Pack Rsns Q2 Current Sense INA169 C Vcc Buffer LM358 VREF Rs 2~3V Clamp bq24610/30 buffer solution
Current sense buffer solution • Function block: Buffer • The 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 voltage • Provides enough current (8mA) to drive SRP/SRN pin. • The LM358is selected to meet these two requirements. L Rsns U1 bq24610 Buffer U5:LM358 Current sense Rs (R6) SRP R3 SRN
Modified Charger Block Diagram 8~14V Vcc Vcc Bias Supply TPS54060 DC Input 35~57V ACN ACP VCC Pre-charge Deeply discharged Battery BATDRV REGN BTST HIDRV PH LODRV GND SRP SRN VFB ACDRV BTST setting CE CE VREF ISET1 ISET2 ACSET TS TTC STAT1 STAT2 PG Vcc Q1 Half Bridge Gate Drive UCC27201 L Pack Thermistor Battery Pack Rsns Q2 Current Sense INA169 C Vcc Buffer LM358 VREF Rs 2~3V Clamp bq24610/30 2~3V clamp circuit solution
2~3V clamp circuit solution • Function block: 2~3v Clamp circuit • If 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 current • Can support SRN pin sink current (8mA) • A simple 2~3V clamp circuit can be created from the bq24610’s 3.3V VREF. L Rsns Current sense Rs (R6) bq24610 SRN VREF R27 C30 VREF
Modified Charger Block Diagram BTST setting 8~14V Vcc Vcc Bias Supply TPS54060 DC Input 35~57V ACN ACP VCC Pre-charge Deeply discharged Battery BATDRV REGN BTST HIDRV PH LODRV GND SRP SRN VFB ACDRV BTST setting CE CE VREF ISET1 ISET2 ACSET TS TTC STAT1 STAT2 PG Vcc Q1 Half Bridge Gate Drive UCC27201 L Pack Thermistor Battery Pack Rsns Q2 Current Sense INA169 C Vcc Buffer LM358 VREF Rs 2~3V Clamp bq24610/30
BTST setting bq24610 R22 REGN BTST C16 R21 • 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.
Modified Charger Block Diagram BTST setting 8~14V Vcc Vcc Bias Supply TPS54060 DC Input 35~57V ACN ACP VCC Pre-charge Deeply discharged Battery BATDRV REGN BTST HIDRV PH LODRV GND SRP SRN VFB ACDRV BTST setting CE CE VREF ISET1 ISET2 ACSET TS TTC STAT1 STAT2 PG Vcc Q1 Half Bridge Gate Drive UCC27201 L Pack Thermistor Battery Pack Rsns Q2 Current Sense INA169 C Vcc Buffer LM358 VREF Rs 2~3V Clamp bq24610/30
Pre-condition deeply discharge battery solution TPS54060 VCC bias supply R46 D8 BAT R47 R10 VREF D7 R31 CE LM2903 VREF • Function block: Pre-condition deeply discharge battery • When 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.
The calculation tool of L, C value and other parameters The calculation tool of L, C value and other parameters can be found in http://www.ti.com/litv/zip/sluc175c Battery charge voltage setting Battery pre-charge/termination current setting Battery fast-charge current setting Iripple_Lout_Vripple LC output filter resonant frequency Fast charge timer TS resistor network
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.
Test result on HPA603 EVM • 1 ISET1 control IBAT • 1.1 ISET1 vs IBAT waveform • 1.2 ISET1 transient • 1.3 ISET1 accuracy • 2 Switching waveforms • 3 Charger start-up or shut-down with CE control • 4 Battery insertion and removal • 5 soft start • 6 efficiency
Modified Charger Block Diagram The charger circuit have to do several modifications. The block diagram of HPA603 EVM: 8~14V Vcc Vcc Bias Supply TPS54060 DC Input 35~57V ACN ACP VCC Pre-charge Deeply discharged Battery BATDRV REGN BTST HIDRV PH LODRV GND SRP SRN VFB ACDRV BTST setting CE CE VREF ISET1 ISET2 ACSET TS TTC STAT1 STAT2 PG Vcc Q1 Half Bridge Gate Drive UCC27201 L Pack Thermistor Battery Pack Rsns Q2 Current Sense INA169 C Vcc Buffer LM358 VREF Rs 2~3V Clamp bq24610/30
1.1 ISET1 vs IBAT waveform • IBAT are proportional to ISET1. The ratio follows the datasheet equation. IBAT ISET1
1.2 ISET1 transient 2 • ISET1 from 1V to 2V (CCM) IBAT ISET1
ISET1 vs Vsns 16 14 12 10 Vsns error (%) 8 Series1 6 4 2 0 0 0.5 1 1.5 2 2.5 ISET1 (V) 1.3 ISET1 accuracy
2 Switching waveforms High side gate High side gate Switching node Inductor current
3. Charger start-up or shut-down with CE control VBAT CE Switching node Inductor current
4 Battery removal and insertion VBAT VIN Switching node Inductor current Ch1 (yellow): Vin Ch2 (blue): Vbat Ch3 (pink): PH 4 (green): IL
5 soft start VBAT VIN Switching node Inductor current Ch1 (yellow): Vin; Ch2 (blue): Vbat; Ch3 (pink): PH; ch4 (green): IL
More Higher input voltage charger: 100Vin_max and 16-cell 34
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:
SMBus High Voltage Charger Solution 8~14V Vcc Vcc Bias Supply TPS54060 DC Input CSSN CSSP DCIN Pre-charge Deeply discharged Battery ACIN VDDSMB BTST setting VREF CE ACOK PVCC BOOT UGATE PHASE LGATE Vcc SMBUS Q4 SCL SDA Half Bridge Gate Drive UCC27201 L Battery Pack Rsns VICM Q5 Current Sense INA169 C ICOUT ICREF R97.5k GND CSOP CSON Buffer LM358 EAO EAI FBO C21 2000p C23 51p VREF Rs 2~3V Clamp R1020k VFB C22 130p R11200k bq24747 1MΩ
Thank you • Questions