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BQ25890: Interrupt when OTG/Boost is enabled.

Mike Snyder
Intellectual 285 points
Part Number: BQ25890
Other Parts Discussed in Thread: BQ25895

Hi! 

I'm trying to manage a system that can either be battery powered or USB powered. 
On boot, I'm able to determine if USB is plugged in via VBUS_STAT = 0x0B

If no USB is plugged in, I set the OTG bit for the boost. 
Once this happens, I no longer get interrupts on USB insertion or removal. 

If USB is plugged in, I leave the boost alone. 
I get an interrupt on USB removal, my firmware turns on the boost, and I'm stuck in the previously mentioned situation. 

When you're using the boost with a battery, is there any way to tell if USB has been inserted or removed? 

Thanks.

  • +1
    TI__Mastermind 31120 points

    Hi Mike, 

    On BQ25890 there is no way for IC to detect if USB has been inserted or removed when in boost mode because VBUS pin, which is both boost output and USB input, is being regulated to 5V.  With the pin already being regulated to 5V the IC cannot detect when a new 5V power source is connected. 

    We have a part from the same family BQ25895 where boost output is PMID rather than VBUS. Due to this BQ25895 is able to detect when a USB is plugged in while in boost mode and exit OTG accordingly. 

    Best Regards,

    Garrett