• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 30 subscribers
  • Views 350 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.

Remove and Restore Power via Interlock on DRV8825

Anthony Syracuse
Prodigy 50 points

I have an application where I need to remove motor drive capability through a safety interlock.  Using a digital input, such as Enable, is not acceptable.  When the interlock relay is actuated, the supply (between 24 V and 32V) will decay very rapidly.  

1) The clock and other inputs will still be active - will this overstress any inputs or damage the part since the internally-derived logic power will also go away?

2) When power is restored, it will rise fairly quickly.  Will this damage the device?

3) Related to 2), if I hold the part in Sleep or Disabled while power is restored, will that reduce any chance for damage?  Thank you!

Tony Syracuse

  • 0
    TI__Mastermind 21320 points

    Hi Tony,

    1) There is no issue in having logic inputs going to the part with the supply removed as long as these inputs to not violate the operating conditions.

    2) I do not see this as being an issue. You should still have the appropriate capacitance for the part on the DRV side of the relay. Again this holds as long as you do not violate the specs of the device. I would ensure that you do not have overshoot when you hot switch the relay.

    3) No damage should result from 2) so this should not be a concern. If you wish to have the bridges disabled when the device comes back up it would be good to assert SLEEP or disable ENABLE when you switch the supply back on.

  • 0 in reply to Nicholas Oborny
    Prodigy 50 points

    Hi Nick,

    Thank you for your response.  I'll be sure to watch out for transients.

    Tony