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UCC28950: Max delay time setting on UCC28950

Mahendra Patel1
Expert 3560 points
Part Number: UCC28950

Hello Team,

As per datasheet, maximum allowable resistor value for RAB, RCD, REF is 90kohm.

Which implied maximum delay time of 1.7uS.

Is there a way to increase this delay time further?

If not, what care needs to be taken in design so that dead time requirement is much lesser than 1.7uS?

Regards,

Mahendra

  • 0
    TI__Mastermind 31580 points
    Hi Mahendra,

    The engineer who supports the UCC28950 is OOO today but you should see a response tomorrow to this post.

    Regards

    Peter
  • 0 in reply to Peter Meaney
    TI__Mastermind 25570 points
    Hi Mahendra

    I'm sorry but 90k Ohms is the max allowed resistor. Normally 1.7us is an adequate delay maximum and I'm not aware of any instance where it has proven to be too short.
    The dead time should be slightly longer than the time needed for the switched nodes to swing from Vin to GND and vice versa - the time is difficult to calculate directly because it depends on stray capacitances in the physical hardware and to some extent on propagation delays in the driving circuitry.
    Do you have a specific reason for thinking that you may need longer ?

    Regards
    Colin