• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 64 subscribers
  • Views 249 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

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.

LM5026: tolerance of the duty cycle of this IC

Sean Liao (Yu-Sheng)
Intellectual 1950 points
Part Number: LM5026

Hi sir, 

My customer is using the LM5026 in PSU project. Few weeks ago got the feedback that PSU shutdown in the field.

After we got the unit and analyzed we found that the duty cycle of the LM5026 is limited then the output voltage can’t reach to regulation level.

So we would like to know the tolerance of the duty cycle of this IC. We can’t find in their datasheet as it show only a graph.

 

Can you help to provide this data?

 

Thanks, Best Regards, 

Sean Liao

  • 0
    TI__Expert 7395 points

    Sean,

    Thanks for sending along. Nice to hear from you. :)

    It looks like we only have typical data available in the datasheet. I can look for some other characterization data but it will still only be for very specific operating point. It may help us to understand a little more here. 

    Can you provide the following information?:

    1) Input voltage range (min, typ, max)

    2) Output voltage

    3) max operating temperature

    4) How many units are in the field?

    5) How many units are not hitting regulation?

    6) Can you describe the "shutdown" that's being seen exactly? Is it failing to startup? It's starting up but not hitting target Vout and regulates only to a lower Vout? Or it's starting up and then shutting off after some time?

    7) Can you provide transformer information like inductance and turns ratio? or xfmr datasheet?

    Regards,

    John

  • 0 in reply to John Stevens
    TI__Guru 73645 points

    Hi,

    There is no test data on the tolerance of maximum duty cycle for clamping. Design check may need to consider 15 to 20% as typical design margin.