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UCC28740EVM-525 auxiliary circuits

Other Parts Discussed in Thread: UCC28740EVM-525

Hello ,

I have a question about UCC28740EVM-525. I have two questions about it.

question 1 :

i found in the secondary side there have a auxiliary circuit. i mean D7, R13, R14 and C9. i want to know what is the function about it. why there need this circuit. 

 question 2 : 

what the capacitor C6 function ?

  • The parts D7,R13,C9 and R14 are not fitted on the board and so have no use in the circuit.

    C6 is a common mode Y capacitor used for noise suppression

  • hi John,thank you for your reply.
    yes . i found D7, R13, C9 and R14 are not fitted on the board.
    i also want to know why the PCB have there place but not soldering? on the other way, if i use these, i mean soldering these on the board what will happen ?
    i think there must have some purpose and meaning about D7, R13, C9 and R14 .
  • The added components spaces were put on the EVM for the user to customize cable compensation if desired.  In the FM region of operation these components would provide a linear offset based upon increased freqquency due to load, in the AM region the change in duty cycle would also help with cable compensation but it would not be quite so linear but still very effective.