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BQ40Z50-R3-DEVICE-FW: suitable charger ics for the bq40z50

R D
Prodigy 10 points

Part Number: BQ40Z50-R3-DEVICE-FW

Hi together,

I'm searching for a suitable ic to charge a battery pack with a bq40z50.

The ic should charge via usb-c and it should communicate with the bq40z50 battery pack (smart charger), furthermore the charge ic should charge the battery pack and supply the host system contemporary with power.

How would be the communication between bq40z50 and host system (infos for state charge), when a second ic (charger ic) is on the smb-bus. Does it works?

I have looked at the following ic:

BQ25790 https://www.ti.com/product/BQ25790#product-details##description

BQ25713 https://www.ti.com/product/BQ25713

Best Regards,

Riccardo

  • 0
    TI__Guru** 105590 points

    Hello Ricardo,

    Usually we recommend having some kind of MCU to deal with any error handling. You will need to select a charger with SMBus functionality for the gauge to report directly to the charger using the broadcast feature: https://www.ti.com/power-management/battery-management/charger-ics/products.html#p1152=1;1&p338=Li-Ion/Li-Polymer&p1341=SMBus&p273=Flash%20Charger;Linear;Switch-Mode%20Boost;Switch-Mode%20Buck;Switch-Mode%20Buck-boost

    Sincerely,

    Wyatt Keller

  • 0
    Prodigy 10 points

    Hello Wyatt,

    Thank you for the fast reply and the link. Other questions have arisen:

    1. The broadcast feature must be configured in the bq40z50 or by the SMBus talking battery charger ic?

    2. Do I have understood it correctly, that there are two approaches to the problem:
    • use a MCU that controls the BQ40z50 with the charger IC
    or
    • use a charger ic that has SMBus and communicates over broadcast with the BQ40z50.

    Would be the architecture looks like in the figure:

    3. How does the communication via host-system, bq40z50 and charger ic look like?

    Sincerely,

    Riccardo

  • 0 in reply to R D
    TI__Guru** 105590 points

    Hello Ricardo,

    Yes that's correct, except it would probably be most efficient for the host system to communicate with the MCU in the second diagram.

    Usually the MCU would be a part of your system and use the battery information to shutdown/change operation depending on the SOC. During charge it can read the gauges reported charging current/voltage and program a smart charger accordingly.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 10 points

    Hi Wyatt,

    Last questions:

    1.Assuming I choose the second architecture for the battery pack, wouldn't the MCU and host system have to be connected to the same SMBus? And won't there be communication errors because host system and MCU are on the same BUS and communicate with the same address (from BQ40Z50) at the same time?

    2. Is it possible to charge the battery pack during operation, with the second architecture?

    Sincerely,

    Riccardo

  • 0 in reply to R D
    TI__Guru** 105590 points

    Hello Riccardo,

    It depends on your system, if your MCU or system has 2 I2C buses you can use that way, or use a I2C selector/mux.

    Yes it should be possible if the charger is stand alone or the MCU relays the information to the charger.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 10 points

    Hello Wyatt,

    Wyatt Keller said:
    Yes it should be possible if the charger is stand alone or the MCU relays the information to the charger.

    Ok, if i choose a charger ic which isn't a standalone one, the MCU should check if a power supply is connected on it and sends the corresponding command or does the charger ic begin automatically to charge?

    Sincerely,

    Riccardo

  • 0 in reply to R D
    TI__Guru** 105590 points

    Hello Riccardo,

    When everything is powered the gauge will start writing the the charge voltage and charge current, I have tested with bq40z50-R4 and bq25710 and when the gauge is configured it will start the charger when the VBUS is applied.

    Sincerely,

    Wyatt Keller