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BQ24725A: USBC

patrick nefos
Expert 1850 points
Part Number: BQ24725A
Other Parts Discussed in Thread: BQ25710, BQ25792, TPS65400, BQ25883

Hi, I am currently using LTC4100 smart battery charger. I see that TI has similar BQ24725A.

On my new design. a request for USB C has come up. Is there a smart battery charger that works with 2S2P (7.2V) pack

that also has USB C PD etc so I can use ONE CHIP SOLUTION? Then for my low voltage supplies, What does TI have similar to

quad LTC3370? This is a fan less design so I need high efficiency (low rds-on fets and low switch frequency). - Patrick

  • 0
    TI__Genius 11850 points

    Hi Patrick,

     

    The BQ25792 and BQ25710 are often used in USB C/PD applications. They are buck-boost chargers that can charge 1s-4s batteries from a wide input voltage range. The BQ25792 has integrated switching FETs, which simplifies the design and reduces the BOM count. On the other hand, the BQ25710 is a charge controller with external switching FETs, which can support applications with higher power and charge current levels. However, at the moment, TI does not have a charger in our portfolio with integrated USB PD power level negotiation. This would need to be handled by a USB PD controller:

    https://www.ti.com/interface/usb/type-c-and-power-delivery/overview.html

     

    Regarding the LTC3370 quad buck converter, here is the TI product page for integrated FET buck converters. I did a quick parametric search, and it looks like the TPS65400 is the most similar to the LTC3370. However, I only support battery chargers, so can you please create a new E2E thread with the TPS65400 in the title? This will help the appropriate team within TI see your questions and provide further suggestions.

    https://www.ti.com/power-management/non-isolated-dc-dc-switching-regulators/step-down-buck/buck-converter-integrated-switch/overview.html

     

    Best regards,

    Angelo

  • 0 in reply to Angelo Zhang87
    Expert 1850 points

    Hi I reviewed your charger parts, do you have smart charger like LTC4100EG#PBF? - Patrick

  • 0 in reply to patrick nefos
    TI__Genius 11850 points

    Hi Patrick,

    The LTC4100 datasheet states that it is a level 2 smart battery charger. Unfortunately, I don't think we have a direct replacement for the LTC4100.

    On its own, the BQ24725A is not fully SBS 1.1 capable as a Level 2 charger. The ChargeCurrent() and ChargeVoltage() register addresses match the SBS spec, but the BQ24725A does not have register 0x16 for the AlarmWarning(). Also, we currently do not have a charger in our portfolio that supports PEC. The BQ24725A can still be used to charge smart batteries, but you will need to disable PEC from the smart battery's broadcasts to the BQ24725A.

    Although we do not have a fully SBS 1.1 capable Level 2 charger in our portfolio, TI does have battery gauges that are SBS 1.1 compliant.  These gauges typically have a broadcast mode where they will communicate with our SMBus chargers (including the BQ24725A) and write to the ChargingCurrent() and ChargingVoltage() registers. You may refer to the following E2E thread for more discussion about this topic:

    https://e2e.ti.com/support/power-management/f/196/t/859947

    Best regards,

    Angelo

  • 0 in reply to Angelo Zhang87
    Expert 1850 points

    BQ24725A: I don't see support for a TEMP PIN (4) from they typical 5 blade smart battery. Did I miss this in datasheet? - Patrick

  • 0 in reply to patrick nefos
    TI__Genius 11850 points

    Hi Patrick,

     

    Several of our other, more integrated chargers have a TS pin which is used to monitor the battery temperature, but you are correct that the BQ24725A cannot monitor the battery temperature on its own. Typically, our SMBus charge controllers are paired with a battery gauge that monitors parameters such as the state of charge, charge voltage, charge current, battery temperature, etc. The host MCU can process this information and control the BQ24725A as needed.

     

    If you are looking for a 2s charger with integrated battery temperature monitoring, you can consider the BQ25883 (boost) or the BQ25792 (buck-boost) instead.

     

    Best regards,

    Angelo

  • 0 in reply to Angelo Zhang87
    Expert 1850 points

    Can BQ25792 operate without host processor intervention similar to SMB1.1 with smart battery? - Patrick

  • 0 in reply to patrick nefos
    TI__Genius 11850 points

    Hi Patrick,

     

    The BQ25792 can charge the battery using the default charging parameters in Table 9-9 without any host involvement. The host MCU can change these register settings through I2C. However, for full SBS 1.1 compatibility, note that the BQ25792 does not have an AlarmWarning() register either.

     

     

     

    To help keep the forum organized, can you please create a new E2E thread with the BQ25792 in the title for any further BQ25792 questions? Thanks!

     

    Best regards,

    Angelo