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Original question:

BQ25895: Input current on VBUS

BQ25895: Input current on VBUS

Christopher Voss
Prodigy 120 points
Part Number: BQ25895


On page 7 of the datasheet, for the parameter I(VBUS_HIZ), the stated test condition is "High-Z mode, no battery, battery monitor disabled"

Is that a typo? How can the IC be in Hi-Z mode without a battery attached? If no typo, is the I2C functional with no battery and High-Z mode enabled ?

  • 0
    TI__Mastermind 25800 points

    Hey Christopher,

    That is not a typo. This parameter is meant to show the leakage current into solely into VBUS. 

    The I2C engine is still active, but HI-Z really means the converter is turned off and the Q1 Reverse Blocking FET is turned off. 

    As far as how the charger can be in Hi-Z without a battery: the HIZ register can be flipped at any moment while a valid source is applied. In this case, it was likely that SYS was the I2C pull-up rail, the HIZ bit was flipped, and the charger transitioned into that mode while the bit remains intact.

    Regards,

    Joel H

  • 0 in reply to Joel Hernandez II
    Prodigy 120 points

    Joel Hernandez II said:

    The I2C engine is still active, but HI-Z really means the converter is turned off and the Q1 Reverse Blocking FET is turned off. 

    So just to confirm, You are saying it is possible to exit HI-Z by I2C command with VBUS and without battery (Assuming the I2C pullup is provided by a different power rail) ?