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BQ25629: USB D+/D- connection and BC1.2 charger detection

Don Foong
Expert 4100 points
Part Number: BQ25629


Hi Team,

We have question from our customer regards to bq25629 application. Hope you can help, thanks in advance.

Our customer is looking at using bq25629 as battery charging for pointing device (Mouse) design. The power is taking from the USB port VBUS.

Customer question:
If my host (computer/notebook) needed the USB communication, how do we able to use the BC1.2 detect feature? since the USB is connected to the MCU (on the Mouse board).

Should we connect the USB's D+/D- to bq25629 in parallel to the MCU?

Look forward to your comments, thanks.


Best regards,
Don

  • +1
    TI__Guru 58461 points

    Don,

    D+/D- pins are used for USB input current limit detection when VBUS power is plugged in. During the charger input current limit detection process, the host must be able to HIZ D+/D- pins so that D+/D- pins are driven by the charger. If the host is unable to HIZ D+/D- pins, a USB switch is needed to isolate the D+/D- pins of the host and the charger.

    Thanks,

    Ning.

  • 0
    TI__Expert 4100 points

    Hi Ning,

    Thanks for your help on this enquiry.

    Please advise how long does the host need to keep the D+/D- in HIZ for the detection process to complete?

    Is there a way to check on bq25629's register when the detection is done?

    Best regards,

    Don

  • +1 in reply to Don Foong
    TI__Guru 58461 points

    Don,

    Upon the completion of input source type detection, VBUS_STAT bits are updated to indicate the detected input source type. Please use VBUS_STAT bits (REGx1E[2:0]) and VBUS_FLAG (REGx21[0]) together to check if the detection is completed.

    Thanks,

    Ning.

  • 0 in reply to Ning T
    TI__Expert 4100 points

    Hi Ning,

    Thanks for your help on this enquiry.

    You have answered the help needed. You may consider closing this thread. Thanks.

    Best regards,

    Don