• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 537 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.

TPS65988: UnableToSource

Eric Hung
Prodigy 250 points
Part Number: TPS65988

Dear Sirs,

PCB Power source from Type C PortA input
I want to move PortA to PortB
Switch MOSFET through GPIO5
If it is 5V, use LDO
If it is 9V/15V/20V, PortA moves to PortB.

PD5V/9V15V can be successful.
But PD20V will be wrong because UnableToSource, as shown below
Purple Line PortA VBUS
Green Line PortB VBUS
I guess it is Timeout.

Each time through the MSP430 command TPS65988 waits for a response of about 100ms
Timing is as follows
1. When PlugInsert
2. Read PortA PDO, move to PortB PDO
CC4_cmdw(SendSourceCap)[120ms]
3. Confirm PortB Active RDO, Re-request PortA PDO,
CC4_cmdw(GetSourceCap)[90ms]
4. Switch GPIO5,
  CC4_cmdw(GPIOSetOutputHigh)[110ms]
5. Power climb
   5Vto20V[250ms]

How can I speed up the TPS65988 response?
Or avoid Timeout

Thank you

Eric hung

  • 0
    Prodigy 250 points

    PD5V/9V15V can be successful. below is PD15V.

  • 0 in reply to Eric Hung
    TI__Mastermind 36756 points

    Hi Eric,

    It looks like the 20V does not ramp in time to meet the PD Specification. Is there any way you can increase the ramp on the 20V Supply? I noticed the dV/dT looks the same for the 15V case, so the timing can be met since the voltage does not need to go as high. However, for the 20V case, the timing is not met as the ramp from 5V to 20V is taking too long. I would suggest increasing the ramp rate of the 20V supply to resolve your timing issue.

    Thank you,
    Eric

  • 0 in reply to Eric Beljaars
    Prodigy 250 points

    Dear Eric(B),

    We have three brands Adapter on hand.
    1. P4
    2. GrenPlue 65W
    3. Millet Type C
    Compare them about 100ms~250ms

    Testing

    Make PortA PDO normal at 9V, climb to 20V, save some time
    But as things get more, they find other problems.

    Picture 190906_Result compares .PNG
    Top left: 9V to 20V success
    Top right: 9V to 20V failure (UnableToSource)
    Bottom left: 5V to 20V failure (UnableToSource)
    Bottom right: 5V to 20V failed with fast Adapter (UnableToSource)

    1. Is it possible to speed up the TPS65988 response?

    2.  What is error reason both right picture

    3.Or other suggested ways

    Thank you

    Eric Hung

  • 0 in reply to Eric Hung
    TI__Mastermind 36756 points

    Hi Eric Hung,

    Can you maybe share a block diagram of your setup? It would help me to understand the application and exactly what you are trying to do with the TPS65988.

    As far as speeding up the response of the TPS65988, we cannot change this timing. The TPS65988 is PD compliant and certified. All relevant transition timings are following the USB Power Delivery specification and adjusting these timings would break that compliance. 

    For the error reason for the images on the right, it looks like there may be a large current spike occurring causing the TPS65988 to go into Over-Current Protection. It looks like the adapter VBUS is dropping a lot when the Power Path in the TPS65988 is closing. If you could measure VBUS current during this event, it would verify what I am thinking. 

    Thank you,
    Eric

  • 0 in reply to Eric Beljaars
    Prodigy 250 points

    Hi Eric (B),
    Later, I experimented with directly controlling mosfet through Msp430, which can reduce delay and current spike.
    But twice the cc4 cmd write still has delay 220ms

    Can I extend the timeout of the TPS65988?

    Otherwise encountering this type of power Adapter will timeout

    Thank you

    Eric