• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 33 subscribers
  • Views 399 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS65987DDJ: USB-C charger identification time

Maurice
Intellectual 971 points
Part Number: TPS65987DDJ


Hi, everyone,


We're designing PC, using TPS65987DDJ.


When we attach USB-C charger (PD adaptor, BC 1.2 DCP, Apple divider, and so on),
how long does it take for TPS65987DDJ to identify USB-C charger
and determine Power Status Register 0x35?


It seems that Apple divier 1~3 chargers take more times to be identified
rather than other's USB-C chargers.

So we want to maximum time required for identifying what USB-C charger or device is attached, and fixing Power Status Register 0x35.

Best Regards,

  • 0
    TI__Mastermind 36756 points

    Hi Maurice,

    This timing is dependent on the device that you are attaching to the Type-C port. PD negotiation time is variable and there is no "maximum time" I would suggest using the Power Status Updates Interrupt from the TPS65987DDJ for your system instead of waiting for a "maximum time". This will send an I2C interrupt to the I2C master to let it know that the Power Status Register has updated.

    Thank you,
    Eric

  • 0 in reply to Eric Beljaars
    Intellectual 971 points

    Hi, Eric-san,

    Thank you for your reply.

    Exactly, you're right.
    PD negotiation is very complicated and we cannot know maximum duration time...


    By the way, in our product PC using TPS65987DDH,
    embedded controller can identify Apple charger by reading "Power State Register 0x3F" correctly
    in the same sequence.

    It implies it takes longer time in TPS65987DDJ rather than TPS65987DDH
    to identify what type of Apple charger is attached.

    Expecially, Apple charger is very simple unlike PD adaptor,
    and if we want to identify it, we only have to watch D+/D- voltage without watching PD negotiation.


    If possible, could you tell me the difference between TPS65987DDH & TPS65987DDJ

    about Apple charger detection ?


    Best Regards,

  • 0 in reply to Maurice
    TI__Mastermind 36756 points

    Hi Maurice,

    The detection has been improved in 87DJ for greater accuracy. The timing is still within the BC1.2 specification.

    Thank you,
    Eric

  • 0 in reply to Eric Beljaars
    Intellectual 971 points

    Hi, Eric-san,

    I understood.

    Thank you for your reply.

    Best Regards,