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BQ25890: OTG question

Mikael Rogberg
Prodigy 70 points
Part Number: BQ25890

Hi,

My understanding of the OTG support is that it makes it possible to power an external device. But if I have the OTG enabled and a 5V level at VBUS, how do I then get noticed on removal/connect. Is it up to the host to monitor the USB-OTG pin or is there some support in the BQ25890 that I have missed?

/Mikael

  • 0
    TI__Guru**** 166246 points

    Mikael,

    OTG is only enabled after

    1. BAT above BATLOWV

    2. VBUS less than BAT+VSLEEP (in sleep mode) - i.e. the power source to VBUS has to be removed first

    3. Boost mode operation is enabled (OTG pin HIGH and OTG_CONFIG bit =1)

    4. Voltage at TS (thermistor) pin is within range configured by Boost Mode Temperature Monitor as configured

    by BHOT and BCOLD bits

    5. After 30 ms delay from boost mode enable

  • 0 in reply to Jeff F
    Prodigy 70 points
    My plan was to use the built in OTG-boost to power some of my electronics that uses 5V (while most of it uses 3v3). Doing so my thought was that I need to detect when an external charger is connected so that I can turn OTG off and let the battery charge. But since this can't be done, and since I just realize that the VBUS might be much higher then 5V (9V/12V), I'll skip to plan B (adding my own boost converter.

    /Mikael