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BQ40Z50-R1: Wakeup without SMBUS

Basil
Intellectual 1620 points
Part Number: BQ40Z50-R1

Dear Team,

I'm using the BQ40Z50-R1 trying to implement following functionality:

Charge FET is OFF, device is in sleep mode.

Is it possible to initiate the charging process and turn the FET back ON without SMBUS communication but by applying a valid power supply?

Could you please advise?

Thanks and best regards,

B

  • 0
    TI__Mastermind 25955 points

    Hi Basil,

    Assuming the Charge FET is not disabled due to a system protection being triggered, the device may be woken from sleep (return to normal mode) in a variety of ways, listed in detail in Section 5.3.1 of the TRM (http://www.ti.com/lit/sluubc1).  If charging is enabled in normal mode, then the Charge FET may turn back on.

    For example, if the Charge FET is disabled in sleep mode due to SLEEPCHG = 0 (default), a return to normal mode may reactivate charging.

    Some ways to wake up sleep mode without sending a SMBUS command (if configured):

    • Using a GPIO on another micro to pull the clock or data pin high
    • PRES pin is toggled
    • Wake Comparator Activates

    To wake from sleep mode with the Charge FET OFF and the Discharge FET ON using the Wake Comparator, voltage across the shunt resistor (between SRN and SRP) would need to exceed the threshold set by (WK1,WK2).  The amount of current required to be discharged to wake immediately will vary based upon the size of your shunt resistor and the threshold selected.  Please see section 5.3.4 for more details.

    Using the PRES pin or pulling either the clock or data pin high may more feasible.

    Sincerely,
    Bryan Kahler