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BQ24160: USB Charger detection function

Yuto Hori
Prodigy 390 points
Part Number: BQ24160

Regarding "8.3.10 D+, D– Based Adapter Detection for the USB Input" in the datasheet, when connected to a specific PC port(SDP), the IC detects CDP/DCP(bit 6-4 in register 02h becomes 101b). Customer checked the waveforms of D+ and D- in primary detection however they can't find any problem.

What could be the cause of this error? And are there any countermeasure?

this error occurs when the PC is in suspend mode. Therefore if the charging IC side draws current, it may destroy the supply source. The MCU side cannot be activated depending on the remaining battery level. Are there any function that does not automatically judge, without setting via I2C?

  • 0
    TI__Guru**** 150285 points

    Hi Yuto,

    The BQ24160 only performs the most basic primary detection per BC1.2, so either SDP or DCP.  Are you certain that the D+/D- pins are not shorted?  I have always seen the BQ24160 D+/D- end in SDP if there is any kind of fault, unless the D+/D- pins are shorted.  Regardless, the charger's VINDPM feature, which is an analog that prevents the input voltage from drooping below preset threshold by clamping the converter duty cycle (which limits the input current drawn).  The default setting is 4.20V, which is too low.  So the host would need to increase to 4.5V at least to prevent USB fault.

    Regards,

    Jeff

  • 0 in reply to Jeff F
    TI__Prodigy 390 points

    Hi Jeff,

    The below picture is the waveforms of D+/D- in primary detection from customer. It doesn't seem to be shorted. Could you give me comments on this? Are there any other possible causes?

    D+/D- in primary detection

  • 0 in reply to Yuto Hori
    TI__Guru**** 150285 points

    Hi Yuto,

    I am not aware of another other causes.  Just to confirm, the D+/D- only sets input current limit on the USB input not the IN input.

    Regards,

    Jeff    

  • 0 in reply to Jeff F
    TI__Prodigy 390 points

    Hi Jeff,

    My apologize and I recieved correct picture from customer side.

    Is Primary Detection performed at the timing circled?

  • 0 in reply to Yuto Hori
    TI__Guru**** 150285 points

    Hi Yuto,

    Following input source attach, primary detection requires at least 90ms but can take up to 500ms to complete. So the D+/D- cannot be accessed by the USB host until after 500ms. So from your scope plot, I do not think D+/D- completed before other communication started on the D+/D- lines.

    Regards,

    Jeff