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UCC28070: PWM duty requirement of 4 phase application using ucc28070

Part Number: UCC28070

Hi team,

My customer  is evaluating to use ucc28070 to implement their power design.

There are few question would like to consult with you.

  • What is the recommendation duty cycle value of sync clock?

  • May we know the definition of tsync? Is it the reciprocal of fsync?
  • What is the suggestion voltage level requirement of  sync PWM signal?

Thank for your kindly help.

  • Hello   ,

    I am attaching a timing diagram that details the timing relationships for the sync input to the UCC28070

    UCC28070_SYNC.pdf

    (1)The min value of sync pulse width is specified as 200nS and the duty cycle of the clock then is really dependent on the required switching frequency of the pfc.

    (2) tsync is the pulse width of the sync waveform.
    It is not the reciprocal of fsync

    (3) The required voltage threshold level on SYNC is 5V typical.
    SYNC can be driven from an open collector on VREF.

    Regards

    John