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UCC28951: Maximum frequency at SYNC in follower mode

AhmadBashar Taji
Prodigy 50 points
Part Number: UCC28951

Tool/software:

Hello,

The datasheet of UCC28951 (page 33) mention that SYNC frequency must be greater than or equal to 1.8 times the converter frequency, but what is the maximum limit?

Regards

  • 0
    TI__Guru* 86286 points

    Hello,

    Your inquiry has been received and is under review.

    Regards,

  • 0 in reply to Mike O'
    TI__Guru* 86286 points

    Hello,

    The data sheet advertises the converter can operate up to 1 MHz.   This is 500 kHz on the primary and 1 MHz on the secondary of the converter.

    The maximum sink frequency (fsink_max)  is 1 MHz.  RT programs the primary switching frequency (fsw) and the internal clock frequency which is 2*fsw.  The master clock is what your are trying to synchronize.

    If you are trying to synchronize to the maximum frequency of 1 MHz, you would have to set the fsw of the UCC28951 to 555 kHz by properly selecting RT. 

    fsw*1.8 = fsink_max

    fsw = 1 MHz/1.8 = 555 kHz

    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,