• State
  • Locked Locked
  • Replies 4 replies
  • Subscribers 29 subscribers
  • Views 855 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.

DRV8813 OCP deglitch timing

RVG
Intellectual 720 points
Other Parts Discussed in Thread: DRV8813

Hi,

Do need advise on the OCP deglitch timing as it is not stated in the datasheet.

However found it from the Application Report, SLVA505 which co-incidentally using the DRV8813 as an example and stated that it was approximately 2.5us.

Any confirmation on this matter?

Thanks.

RVG

  • 0
    TI__Guru 55615 points

    RVG,

    Good find!  Sorry you had to go through this much digging.

    Yes, I can confirm it is typically 2.5us and can be as high as 3.1us.

     

  • 0 in reply to Ryan Kehr
    Intellectual 720 points

    Hi Ryan,

     

    Thanks for the information.
    Would you also be able to share with me on the minimum value? As this would be a critical value to understand the period which OCP will trigger.
    Thanks.

    RVG

  • 0 in reply to RVG
    TI__Guru 55615 points

    RVG,

    I did some more analysis on this topic and realized my initial understanding was not correct.  I apologize for the incorrect post on the maximum deglitch time.

    The actual deglitch range is 1.6us - 1.9us.  Simply knowing the deglitch time window is not giving you the full story.  There are delays in the system that add to this time.  In addition to the time to ramp the current above the threshold, there can be up to 100ns delay between the analog circuitry responding to the OC event and notification to the digital logic.  After the deglitch time expires, there can be another 200ns delay to disable the output FETs. 

    When looking at the output waveform, you will see a number slightly higher than the deglitch range due to these delays. 

     

     

  • 0 in reply to Ryan Kehr
    Intellectual 720 points

    HI Ryan,

    Thanks for the clarification.
    Is it correct to say that the effective trigger of OCP is 1.6us - 1.9us, however response time is delayed due to the internal circuitry?
    If the OC hits the min of 1.6us, the OCP will trigger. As the output waveform, the response time will be slightly longer.

    The most essential is that the min, typical and max value of the trigger of the OCP as it will taken into consideration if the motor driver fits the motor.
    If the torque requirement is above the rated current for that min period, the driver will not be applicable.

    Regards,

    RVG