• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 34 subscribers
  • Views 493 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.

TPS65982: AUX channel connection for DP sink applications when using a MUX

Marcis Greitans
Prodigy 240 points
Part Number: TPS65982
Other Parts Discussed in Thread: TUSB1064, HD3SS460

Dear TI,

I am planning to use the TPS65982 device in a DisplayPort Alternate mode sink application where I need all 4 DisplayPort lanes and also billboard functionality. I also need to use an external MUX and Redriver (such as the TUSB1064). Do I need to connect the AUX channel to the TPS65982? Or can I connect it directly to the TUSB1064 and leave the corresponding TPS65982 pins unconnected?

The issue arises when the TPS65982 and the TUSB1064 both switch the AUX channel polarity, resulting in the polarity being switched twice. Maybe it is possible to turn off the AUX channel multiplexing functionality of the TPS65982?

Thanks!

  • 0
    TI__Mastermind 30000 points

    Hello,

    I've assigned this issue to the relevant expert who will get back to you shortly

  • 0
    TI__Genius 12700 points

    Hi Marcis,

    Yes you may directly connect them to the TUSB1064. However, if you do not plan to use them on the TPS65982, I recommend grounding those pins with between 1-kΩ and 5-MΩ resistance.

    Thank you,

    Hari

  • 0 in reply to Hari Patel1
    Prodigy 240 points

    Thank you for your reply. Continuing with this could you please explain how to interpret section 10.2.2.2.2 of the TPS65982 datasheet where it states that "Although the HD3SS460 is able to multiplex the required AUX_N/P signals to the SBU_1/2 pins, they are connected through the TPS65982 for additional support of custom alternate mode configurations." To me it seems that this means the DisplayPort Alternate mode is not supported unless the AUX channel is connected to the TPS65982, or am I mistaken?

    Kind regards,
    Marcis Greitans

  • 0 in reply to Marcis Greitans
    TI__Genius 12700 points

    Hi Marcis,

    That section is just mentioning that instead of connecting to HD3SS460, which would've also worked, you can connect the SBU pins to the TPS65982 if you would like to support other alternate modes as well. For example, the TPS65982 along with DisplayPort, it also support Thunderbolt for example which would use the SBU pins as well I believe. 

    Therefore, if you are only supporting DisplayPort, you do not necessarily have to connect the AUX pins from the TPS65982. You may also reference the TUSB1064 datasheet Section 9.2.3 which goes into a similar setup using the AUX pins from only the TUSB1064.

    Thank you,

    Hari