• State
  • Locked Locked
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 346 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.

TPS65987D: USB PD negotiation

Rutvik Naik
Prodigy 60 points
Part Number: TPS65987D

Tool/software:

I am using USB PD controller part #TPS65987DDHRSHR for my new design. 

It is clear that the PD controller can detect the USB PD voltages: 5V, 9V, 15V and 20V as per the source capability and provide o/p to user through it's GPIOs.

But one of my use case is that I want to run my system on USB 2.0/3.0 source in low power mode for which the PD controller has to detect the non-PD 5V input and provide the input to processor. As 2.0 and 3.0 interface does not come with PD capabilities because it does not have CC lines, how can my processor decide whether to boot in low power mode or full power mode. In the case of BC1.2, the power negotiation can happen on DP DM lines but that still leaves the USB 2.0 and 3.0 use case.

Is there any way that the PD controller can detect a non-PD 5V source and communicate the same to processor through I2C or GPIO?

  • 0
    Prodigy 60 points

    Additionally, I also have the PD controller EVM part #TPS65987EVM with me so I can run any PoC for that matter. 

  • 0 in reply to Rutvik Naik
    TI__Genius 12835 points

    Hi Rutvik,

    Any USB Type-C port has CC signals, and must use them to configure power/data. The PD controller can detect both PD and Type-C only non-PD connections on the CC signals from the physical connector. If you are not using CC signals, then you are not using a Type-C port.

    Can you clarify what is low power and full power modes you are referring to? What does the processor need to know to decide whether to boot in low power/full power mode?

    Best,

    Alex

  • 0 in reply to Alex Liu
    Prodigy 60 points

    Hi Alex,

    I am using a USB type-A to USB type-C port. In this case, CC lines will not be present. But the source can still provide 5V @500mA (USB 2.0) or @900mA (USB 3.0). Now what I intend to do is, as my system can not boot on it's full capability (as it is power hungry and requires >15W of power), I want to communicate with my processor through PD controller that the available source is only 2.5W or 4.5W capable, so that it can boot on low power mode. 

    But to achieve this, the PD controller has to somehow communicate with processor about the power source. My doubt is that, can PD controller detect a non-PD power source such USB 2.0 and 3.0.

    -

    Regards,

    Rutvik

  • 0 in reply to Rutvik Naik
    TI__Genius 12835 points

    Hi Rutvik,

    TPS65987D can detect a USB2.0/3.0 non-PD/Type-C power source through BC1.2 detection. This detection can identify BC1.2 complaint USB2.0/3.0 power source devices on the D+/D- signals.

    After detection, through I2C interrupt events and register reads, or GPIO events, a processor can determine what power level is available at the port. However, if the processor is not powered when the USB2/3 charger is connected, I am not sure how you would communicate the available power information to the processor.

    Best,

    Alex