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TPS65982 PR-swap using e-marked cable

masahiko shimizu
Guru 11235 points
Other Parts Discussed in Thread: TPS65982

TPS65982 PR-swap using e-marked cable

Hi,

My customer has a issue at competitor device.
Could you tell me whether this issue occur at TPS65982 or not, please?

[issue]
Customer is using e-marked cable.
This cable has low power function.
Ra resister in cable will be opened after first attach of Source and Sink for low power.

Then, during connecting Source and Sink, PR-swap is operated.
As a result, PD controller can not detect e-marked cable.

Competitor device looks Ra resister for detection e-marked cable. 

[Question]
Q1: Does TPS65982 have this issue, too?

Q2: When TPS65982 operate PR-swap, Does TPS65982 looks that whether there is Ra, or not?


Best regards,
Shimizu

  • 0
    Guru 11235 points
    Hi,

    How is the progress?

    Best regards,
    Shimizu
  • 0
    TI__Mastermind 30310 points
    Shimizu-san,

    1) The TPS65982 does not have this problem and is always able to detect Ra of an e-marked cable and communicate with the cable when necessary.

    The Policy Engine of the TPS65982 is written in a way to automatically request a VCONN_Swap during a PR_Swap to Source (to determine 3 or 5 Amp current capability) or during a DR_Swap to DFP (to determine 5 or 10Gbps data rate capability) via a Discover Identity message sent to SOP'

    2) TPS65982 always determines if Ra is connected. Ra is recognized at the initial Type-C cable plug event and this data is retained for future use during all PD & Alt. Mode negotiations
    -Ra will be identified if the cable is plugged in 1st, then the far-end system is plugged in later (Rp or Rd)
    -Ra can also be identified if the cable is plugged in with the far-end system already connected (Ra + Rp or Rd simultaneously)

    The TPS65982 and related parts work very well with e-marked cables and automatically adjust Source current capability if the cable does not support 5 Amps (100W,20V,5A PDOx will be adjusted to 60W,20V,3A PDOx) so that the Sink cannot accept an invalid power contract and damage the cable.