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UCC28950: how many consecutive cycle by cycle current limit thresholds need to be seen before controller enters shutdown mode?

Nitish Agrawal
Expert 1595 points
Part Number: UCC28950

Tool/software:

Hello,

We are noticing that the UCC28950 shuts down near full load operating point.

It is our understanding that there the cycle-by-cycle current limit threshold needs to be reached consecutively for a certain amount of time before the controller shuts down.  Is that correct?

If yes, what is the cumulative time of the consecutive cycles (or the number of consecutive cycles) during which the cycle-by-cycle current limit threshold of 2V needs to be reached?

We would appreciate clarification about this.

Regards,

Nitish Agrawal

  • 0
    TI__Guru* 85926 points

    Hello,

     

    Your inquiry has been received and is under review.

     

    Regards,

  • 0 in reply to Mike O'
    TI__Guru* 85926 points

    Hello,

     

    The cycle by cycle current limit will discharge the soft start capacitance based on IDS.  When the SS capacitor discharges from 4.65 V down to 3.6 V the device will stop switching and enter hiccup mode.  It is not based on the number of cycles but how long it takes to discharge the SS capacitor.

    Please see below for details on how over current protection hiccup mode works.

    Thank you for interest in Texas Instruments (TI) products.  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.

    Regards,