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UCC28951-Q1: UCC28951-Q1

Rajashekar Koutla
Intellectual 590 points
Part Number: UCC28951-Q1


hello 

1) What is the use and function, importance of diodes D2 and D7 in the figure no 56 of the datasheet UCC28951-Q1 and how to calculate the ratings of those components ? if they are not connected , what will be the cause and effect ?

2) how to calculate the values of R3 and R7 in the figure no 56 of the datasheet UCC28951-Q1 and what is the use of those resistors ? and if not connected what happens

thanks and regards

Rajashekar

  • 0
    TI__Genius 9140 points
    Hi Rajashekar,
    I need your double check of your question.
    1)I can not find D2 and D7 in page 56 in the UCC28951-Q1 datasheet. Can you figure out ?
    2)R3 in the datasheet page 56 is used for DLEB, and R7 is the output voltage divider. I think you are not asking these two resistors. please check it.
  • 0 in reply to David Huang33
    Intellectual 590 points

    Hello David

    you will find that in the page number 57 of the datasheet UCC28951-Q1ucc28951-q1.pdf

    those diodes are between the gate terminal and source pin of each input side mosfet.

    and in same figure there will be the resistors which are beside of the diode.

    thanks

    Rajashekar

  • 0 in reply to Rajashekar Koutla
    TI__Genius 9140 points
    Hi Rajashekar,
    R7 is used on the GS pin for the protect of static electricity, the value is not so important, 1Kohm~100Kohm is recommended.
    R3 is the turn on and turn off resistor of the mos, you can change this resistor to change the speed of the mos.
    D7 is used to protect the mos GS voltage that do not over the maximum GS rating. the value should be a little less than the maximum GS rating of the mos.
    D2 is used in series to do demagnetization of the driving transformer.

    So my suggestion is you can not remove any of these parts.