• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 319 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.

WEBENCH® Tools/LM25085: Unable to get the design for output current greater than 3A for Input 5.6V.

Preethi Rajagopal
Prodigy 210 points
Part Number: LM25085


Tool/software: WEBENCH® Design Tools

Hi,

I am using LM25085 in my design.

My design considerations are:

V in = 5.6 to 28V

V out = 5V

I out = 6A

When i tried getting the design using Webench tool, it showed "Duty Cycle exceeds". Please help. 

When I increase the minimum input voltage , i can able to get the design. Is it because of the lesser switching frequency?

Please help here...

I have attacehd my design here.  

  • 0
    TI__Mastermind 40130 points
    Hello Preethi,

    Webench (WB) uses a duty cycle (DC) limit algorithm before computing the design. The limit is being violated with your specification and it relates to the switch frequency, the RDSon of the Top FET and the DCR of the inductor that WB is trying to select.

    However, in practical terms if you do approach 100% DC, the LM25085 is capable of yielding a DC of 100% and therefore your design will exhibit a small drop out that will be slightly lower than 5V regulation point, as a result, when you approach 5.5V in with 6A out.

    Again, this will vary depending on the parameters I mentioned above.

    Hope this helps?


    David