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BQ24297: USB communication

Jamie Tseng
Intellectual 2405 points
Part Number: BQ24297

Hi Team,

Could you please help check if there is any problem with the following connection?

1: BQ24297 first judges D+/D- according to BC1.2 to set the current.
2: After the current setting is completed, D+/D- pins will be HIZ once the input current detection is complete.
3: At this time, the CPU detects a normal USB communication packet and starts communication.

Thanks and best regards,

Jamie

  • 0
    TI__Mastermind 46691 points

    Jamie,

    1. The device can work with 5V 3A input USB type-C charging, but it can’t detect Type-C. A USB interface is needed. After BQ24297 charger input current limit detection is complete, the host may modify the input current limit via I2C to the desired value if needed.

    2. Yes. In addition, when the BQ24297 is doing input current limit detection, the host and other components connecting to D+/D- lines should be able to HIZ D+/D- lines.

    Thanks,

    Ning.

  • 0 in reply to Ning T
    Prodigy 90 points

    Dear Ning,

    So the BQ24297 can be connected in this way, the CPU's USB host (OTG port) or device port d+/d- is connected to the d+/d- of the BQ24297 and the d+/d- of the USB TYPE C connector.

    When doing BC1.2 detection, the devices on the USB channel will not affect each other.


    1: When BQ24297 is doing input current detection, is there any action or setting required by the CPU?


    2: After the BQ24297 input current is detected, the USB D+/D- can communicate normally. If necessary, the input current limit can be reset through I2C. Is this understanding correct?

    Thanks,

    HP.

  • 0 in reply to hp lin
    TI__Mastermind 46691 points

    HP,

    1. The host should HIZ D+/D- lines when the charger is doing the input current limit detection.

    2. After the input current limit detection is complete, the host may adjust the input current limit via I2C as needed.

    Thanks,

    Ning

  • 0 in reply to Ning T
    Prodigy 90 points

    Hi Ning,

    How much time is need when the charger is doing the input current limit detection?

    (ex:330ms or ,,,,,,)

    Thanks,

    HP

  • 0 in reply to hp lin
    TI__Mastermind 46691 points

    HP,

    The input source type (i.e. D+/D-) detection time is dependent on the input source plugs in. Typically the D+/D- detection could take up to 1000ms depending on the adaptors.

     

    Thanks,

    Ning.