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DRV8328: nFAULT - deglitch time and power consumption calculator

NY
Expert 3040 points
Part Number: DRV8328

Hi team,

my customer want to know the followings, please answer.

1)  nFAULT – deglitch time

2) Power consumption calculator

Customer think that the power consumption can change according to the gate capacitance of the external FET. When they design DRV8328, they request us to provide power consumption calculator.

Would it be possible to provide it?

  • 0
    TI__Mastermind 18981 points

    Hi NY, 

    1. nFAULT itself does not have a deglitch time as it is not a fault monitor
      1. the various fault types reported by this nFAULT pin, however, may have deglitch timers depending in the fault category 
      2. see this example below from the datasheet for BST_UV type fault deglitch time
    2. As an initial resource, here is an app note explaining the gate charge impact on average gate-drive current 
      1. Smart Gate Drive: https://www.ti.com/lit/an/slva714d/slva714d.pdf

      2. DRV835x datasheet also has a section on this: https://www.ti.com/lit/ds/symlink/drv8350.pdf
        1. not the same device, but some useful info to consider on page70, section "9.2.1.2.5 Single Supply Power Dissipation"
      3. we will follow up with the team to see if there's a calculator resource we can share for this device 

    Best Regards, 
    Andrew 

  • 0
    TI__Mastermind 18981 points

    Hi Yada-san, 

    Looks like this thread is already being discussed thru email thread w/ Dung, Aaron, and myself

    Please let us know if you require additional assistance on this. Thanks! 

    Best Regards, 
    Andrew 

  • 0
    TI__Mastermind 23426 points

    Hey NY,

    I just wanted to provide some information on the power calculation. The DRV8328 datasheet section 10.3.1 shows the formulas needed to calculate the power dissipation based on the loss type.

    IGVDD = number of MOSFETS switching * Qg (total gate charge of the MOSFET) * Switching frequency.

    I hope this offers some clarification. Please feel free to reach out with any questions you might have.

    Best Regards,
    Akshay

  • 0
    TI__Mastermind 23426 points

    Hey NY,

    I am closing the thread, but feel free to reach out if you have any more questions.

    Best Regards,

    Akshay