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BQ25790: USB host/charging port detection ready

Pasi Lassila
Prodigy 55 points
Part Number: BQ25790

Related to https://e2e.ti.com/support/power-management/f/196/p/959057/3543576

I need charger detection via USB data pins. However the same USB pins are used by the CPU. CPU can be unpowered so the USB pins need to be muxed.

I added a USB2.0 HS compatible mux.USB data pins are connected to the charger IC by default. I need to control the MUX to connect data pins to CPU after BQ25790 USB host/charging port detection is ready.
Is PG signal related to USB host/charging port detection or is it voltage detection only?
The answer to my preivous question says BQ25790 needs 2s max. for detection. I could use some kind of timer circuit but it would be better if PG or some other signal can be used from BQ25790 IC.

  • 0
    TI__Guru**** 165886 points

    Hi Pasi,

    The /PG signal goes low when a valid 5V supply is found.  D+/D- communication continues after that, especially if HVDCP detection is enabled. Can you use a combo of /PG and /INT pin to determine when to read the charger's DPDM status register bits in register 1D?  That will tell you for sure.  With HVDPC detection disabled, the USB1.2 D+/D- complete is typically the next /INT pulse after /PG goes low, assuming no other event triggers /INT or the host software has masked all other /INTs. With HVDPC detection enabled, the D+/D- complete is either the 3rd or 4th /INT pulse after /PG goes low, assuming no other event triggers /INT or the host software has masked all other /INTs. 

    Regards,

    Jeff