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BQ25895: Low Quiescent Current Requirement

PURUSHOTHAMAN P
Prodigy 50 points
Part Number: BQ25895
Other Parts Discussed in Thread: BQ25620

Tool/software:

Hi TI Team,

We are using a BQ25895RTW chip in a low power application device.

In our design Vbus = 5V and Vbat=3.7V. Vbus is always present in our device.

As per our customer requirement, during our device sleep mode current consumption should be less than 200uA. But our battery charger chip BQ25895 quiescent current (3mA) itself very high compared to our requirement.



Is that any register configuration available to reduce the quiescent current ? or Any other way to reduce the quiescent current ?

Please help us on this requirement and provide the solution for the same. 

  • 0
    TI__Guru** 103925 points

    Hello,

    We are looking into your question and will provide a response by the end of the day.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    TI__Mastermind 25805 points

    Hello, 

    Please see my comments below. 

    PURUSHOTHAMAN P said:
    As per our customer requirement, during our device sleep mode current consumption should be less than 200uA.

    Is it acceptable for the converter to be turned off during your device sleep mode? If so quiescent current can be significantly reduced from 3mA by enabling HIZ mode. HIZ mode is enabled/disabled via REG00[7]. 

    Best Regards,

    Garrett

  • 0 in reply to Garrett Kreger
    Prodigy 50 points

    Hello,

    Our Battery charger IC shouldn't turn off during our device sleep mode. Because, our MCU powered from the Battery charger IC output power rail.


    Also, we tried the HIZ mode in our device. We have tested Battery charger on the following condition,


    Vbus=5V & No battery for the BQ25895 and we enabled the High Impedance mode (HIZ). After enabling HIZ mode, the battery charger output voltage is reduced to 0V. This HIZ mode automatically goes back to normal mode after some time. 

    So, please guide us on this to move further for our requirement.
  • 0 in reply to PURUSHOTHAMAN P
    TI__Mastermind 25805 points

    Hello, 

    Please see my comments below.

    HIZ mode turns the buck converter off, hence why you observe 0V at output and current draw is much lower. If you need VBUS input to continue to power components at VSYS then enabling HIZ mode will not be a good solution for you. 

    Unfortunately, the BQ25895 device cannot meet less than 200uA requirement with converter remaining on. The BQ25620 IC by comparison has lower current consumption, but still draws typical 450uA with converter switching. 

    Best Regards,

    Garrett