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UCC28950 at Max Duty cycle

K.Hamamoto
Guru 12155 points
Other Parts Discussed in Thread: UCC28950

Hi

Our customer evaluate UCC28950 on their board. However at low input voltage the output goes down below setting voltage.

They checked duty cycle at Vi=33V and Vi=48V. The duty cycle is the following waveform. (upper is A and D, lower is B and C)

  

>> Question is 

 1. How much the minimum time of between OUTA and OUTD. (OUTB and OUTC)?

 2. How can we calculate the value (minimum time) if it is limited by Duty cycle or other parameter?

Please let me know if you have any question.

Regards,

Koji Hamamoto

  • 0
    Guru 12155 points

    Hi

    I am sorry for rush. I would like to ask you about especially Q1. ( How much is the limit time of between OUTA and OUTD?)

    This time has been limited in 200ns on customer's measurement even if the fsw is changed.

    Also Duty max is specified above. That means Off time (OUTA-OUTD) is 500ns @100kHz D=95%. Is that correct?

    Regards,

    Koji Hamamoto