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BQ25895: 3.1A without USB

Serge R
Prodigy 80 points
Part Number: BQ25895


Hi,

Is it possible to force the max current 3.1A on PMID pin if i don't use the USB interface but just by I2C or by a pin configuration?

Best Regards,

Serge.

  • 0
    TI__Guru**** 171456 points
    Serge,

    In charging mode (current flowing from VBUS through the buck converter to SYS/BAT), you can force the input current limit, sensed through the FET between VBUS and PMID, to max by shorting D+=D- and by setting the ILIM resistor to allow 3.1A or shorting pin to GND. Keep in mind the input FET that connects VBUS to PMID only senses input current then tells the buck converter not to allow more output current. In OTG boost mode (current flowing from BAT through the buck converter working in reverse as a boost converter to PMID), there is no current limit.
  • 0 in reply to Jeff F
    Prodigy 80 points
    Understand, thank you very much Jeff!
  • 0 in reply to Jeff F
    Prodigy 80 points
    I have an awful doubt by reread your answer. You mean the RBFET cannot drain directly the current from VBUS to PMID when an adapter is connected to VBUS? That is to say it cannot possible to have a voltage on PMID output if the boost mode is disabled?
  • 0 in reply to Serge R
    TI__Guru**** 171456 points

    Serge,

    The voltage at VBUS will be seen at PMID but there is no current limiting by the RBFET itself.  The RBFET only measures current.  Any current pulled from PMID will not be available to provide a power to SYS and/or the battery at BAT.  PMID has no short circuit protection so if pull too much current (>5A) you could damage the RBFET.