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BQ25890: How does it work when it is supplied from USB?

Takanori Yuzawa
Intellectual 1490 points
Part Number: BQ25890

Hi team

Could you let me know about if it is OK or not under the condition below?

1. It works correctly when it is decided the current by using ILIM and ICO.
2. CE_=LO without battery.

Best Regards,
Takanori Yuzawa

  • 0
    TI__Guru**** 167146 points

    Takanori-san,

    Regarding 1, D+/D- detection determines whether the port is SDP, CDP, or DCP and sets the input current limit accordingly.  The ILIM resistor clamps the maximum input current to a value which may be lower than the value set in the IINDPM register by D+/D- detection.  If too much input current is pulled and the adapter starts to collapse, resulting in VINDPM activating, the ICO circuitry finds a new, lower input current limit value that prevents VINDPM.

    Regarding 2, it is okay for /CE=LO without battery.  This results in the battery pin voltage varying between recharge voltage and BATREG voltage as the charger varies between charging and not charging.  The STAT pin blinks to indicate this. 

  • 0 in reply to Jeff F
    TI__Intellectual 1490 points
    Hi Jeff-san

    Thank you for your information.
    For #1, is it OK to be supplied from USB voltage when the current is decided ILIM and ICO?

    Best Regards,
    Takanori Yuzawa
  • 0 in reply to Takanori Yuzawa
    TI__Guru**** 167146 points

    Yes.  ILIM allows you to clamp the input current limit. If the ILIM clamp isn't low enough then  ICO actually finds the maximum power capability of the USB port.