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UCC5870-Q1: STP Shoot Through Protection clarification with TDEAD non-zero

David Stotz
Prodigy 140 points
Part Number: UCC5870-Q1

We would like some clarification on the Shoot Through Protection fault function when TDEAD (in CFG1) is non-zero.

Our system is seeing the STP_FAULT flag set  but TDEAD is non-zero.

Is the gate driver detecting that IN+ and IN- are both high after the TDEAD time has expired?  The datasheet reads as if maybe STP_FAULT is only set if TDEAD is zero.

Any help would be appreciated!

  • +1
    TI__Expert 8165 points

    Hi Stotz,

    Thanks for your interest on the UCC5870 part. The dedicated application engineer for UCC5870 is on vacation. He can add additional details if you have more questions.

    Thank you for pointing this out. This is something we have noticed and will add further clarification in the next revision of the datasheet.

    If tDEAD is set to non-zero and IN+ goes high after IN- goes low but before the dead time is up the STP fault will trigger if the fault is set to report. After reporting the STP fault the gate driver output will follow the fault action programmed in CFG3[FS_STATE_STP_FAULT]. The fault action can be set to pull the output high, low, or have no action. If set to no action the gate driver output will go high after tDEAD.

    You can leave the fault report and set to no action if you would like the system to know if IN+ is going high before the programmed tDEAD expires. Alternatively you could set the STP to not report by programming CFG2[STP_FAULT_P] = 1b = Do not report. This can be done when both high side and low side gate drivers are interlocked through the hardware. The gate driver will introduce the programmed tDEAD to prevent shoot-through. Hope this helps.

    Thanks

    Sasi

  • 0 in reply to Sasikala Thangam
    Prodigy 140 points

    Thank you for the detailed response!  This is perfect!