• State Resolved
  • Locked Locked
  • Replies 7 replies
  • Answers 1 answer
  • Subscribers 30 subscribers
  • Views 281 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.

DRV8320: Recovery time of nFault pin .

Kengo.Y
Guru 11245 points
Part Number: DRV8320

Hi team,

I'd like to know about the recovery time of nFault pin.

In the case of the auto-recovery fault such as UVLO,
how long does it take for the nFault pin to be Hi-Z after the state is restored?

Sincerely.
Kengo.

  • 0
    TI__Mastermind 23045 points

    Hello Kengo-san,

    Thank you for your question and for posting to the MD forum. I will review it and get back to you as soon as possible.

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    TI__Mastermind 23045 points

    Hello Kengo-san,

    The nFault pin on DRV8320 only operates in two states because it is being pulled up to Vcc via a pullup resistor, so when no fault conditions are detected the voltage will be high and in a fault condition such as UVLO it is pulled low. The nFault pin will stay low until the condition is cleared.

    I think the confusion was that in some fault conditions the gate driver pins will be the ones to enter a Hi-Z state, but nFault does not enter a Hi-Z status. I hope this clears the confusion and feel free to let me know if you have any questions!

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    Guru 11245 points

    Hi Isaac-san,

    Thank you for your reply.

    How long does it take for the fault condition to be cleared and nFault to return to High?

    Sincerely.
    Kengo.

  • 0 in reply to Kengo.Y
    TI__Mastermind 23045 points

    Hello Kengo-san,

    It mainly depends on the fault that you are running into and the type of device you are using (Hardware version or SPI version). 

    There are a couple of different methods from recovery after a fault occurs. For example UVLO is automatic. Others are latched which require you to clear using an enable pulse 8 to 40 us long in order to clear the faults. In some configurations they use the retry where it will retry in 4ms to see if the condition still exists. Quantifying the time can be a little difficult since there are various options, but I hope this helps you understand the difference between each one.

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    Guru 11245 points

    Hi Isaac-san,

    Thank you for your reply.
    Sorry for the lack of my information.

    For example, UVLO is automatic recovery.
    In the case of this failure, how long does it take for the fault condition to be cleared and nFault to return to High?

    Sincerely.
    Kengo.

  • 0 in reply to Kengo.Y
    TI__Mastermind 23045 points

    Hello Kengo-san,

    Thank you for the clarification. I should be able to collect timing of this for you in the lab, not sure if I will have more timing results for you either today or tomorrow. I will send you an update as soon as I have the info.

    Best,

    Isaac

  • +1 in reply to Isaac Lara
    TI__Mastermind 23045 points

    Hello Kengo-san,

    I took a measurement on the EVM, it looks like once the conditions are met clearing nFault going high took ~1.2us. The timing from meeting the fault condition to nFault starting to go high is not as exact since I cannot get a fine enough measurement on the scope but it looks like it is approximately ~50-70us.

    If there are other components on your nFault pin then the rise time might vary. On the EVM we have an LED to indicate when there is a fault so if there is no LED on your system then rise time my vary.

    Best,

    Isaac