• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 1 answer
  • Subscribers 31 subscribers
  • Views 343 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.

DRV8328: Clarification for Turnoff time / Minimum Reset Pulse Time

Ue
Genius 17165 points
Part Number: DRV8328

Hi all

My customer is using the DRV8328 and they are not sure how to interpret the datasheet:

For tSLEEP they find only a max value of 20us, is that correct or should that rather be the min value ?

...and if so what is the max value ?

For tRST we specify "Minimum Reset Pulse Time" with a min value of 1us and max value of 1.2us, thats also somewhat confusing, can you clarify ?

Best regards

Ueli

  • 0
    TI__Genius 13900 points

    Hi Ueli,

    Thank you for posting to the Motor Drivers forum!

    The tSLEEP max value is correct.

    To clarify the tRST, whenever device latched faults occur, the DRV8328 goes into a partial shutdown state, and when the fault gets cleared, the device can be re-enabled by sending a reset pulse on the nSLEEP pin. The minimum time is the how much time the nSLEEP pin has to be pulled low for the device to be re-enabled. On the other hand, if you were to exceed the maximum time specified for tRST, then the device will start a complete shutdown sequence. More detailed information can be found in section 8.4.1.3 Fault Reset (nSLEEP Reset Pulse) of the datasheet.

    Best,

    ~Alicia

  • 0 in reply to Alicia Rosenberger
    TI__Genius 17165 points

    Hi Alicia

    Thank you for the quick reply. Maybe we can schedule a call as I am not sure I fully understand the specification.

    Or maybe you can provide a timing diagram to illustrate the behavior ?

    The DRV8328 is evaluated to be a 2nd source to the 

    MP6531A  5V - 60V, Three-Phase, Brushless, DC Motor Pre-Driver with Separate HS/LS Control

    https://www.monolithicpower.com/en/products/motor-drivers-and-motor-controllers/bldc-pre-drivers-and-integrated-solutions/mp6531a.htm

    and the customer has found a difference in the behavior, meaning it is not possible to qualify our device as a 2nd source unless they modify their software.

    Best regards

    Ueli 

  • 0 in reply to Ue
    TI__Genius 13900 points

    Hi Ue,

    Could you clarify what difference was noted by the customer? 

  • +1 in reply to Ue
    TI__Mastermind 18981 points

    Hi Ueli, 

    closing out this e2e thread as we've resolved over email.

    To document the email's conclusions here in e2e forum, what was discovered was that: 

    • t_rst (reset pulse time period) from customer should target middle of that range (1.1uSec) 
    • this will help ensure that the pulse is long enough to take the device out of operational mode (and into reset mode)
    • and this is also short enough to stop the device from transitioning into full shutdown mode

      other sections of the datasheet such as 'operational modes' and 'pin configuration' should have good descriptions to further elaborate on this behavior 

    Best Regards, 
    Andrew 

  • 0 in reply to Andrew Liu
    TI__Genius 17165 points

    Hi Andrew

    Thank you for your support.

    Best regards

    Ueli