Original question:
Hello,
A few days ago M. Youhao Xi said to me that I should try to use the Excel calc design tool for LM5185.
When trying to use it I have a problem:
When I cange transformers turns ratio, all the recommended values are being deleted:
Before:
After:
Have you an idea to fix the problem please ?
Hi Thomas,
Thank you for posting. I remember our discussion :-)
I think the problem that you have is the input number that you gave: Excel spread does not recognize a comma sign as the decimal point. Please use "0.1" but not "0,1".
Some idea about using the spreadsheet: The recommended turns ratio is 1 : 6.4, but this is beyond the limited number of turns ratio selections included by the calculator. The max turn ratio supported by the calculator (not limited by the LM5185 device) is 1 : 5. If you want to use 1 : 6, you can split your output to two rails, like 100V and 20V, and choose the dual output design, and all primary side selections would apply to a 1:6 turns ratio, single 120V output rail. The only think that you need to take care is the secondary circuits by the calculator would be in series, and the voltage rating should be summed up for the series components. The turns ratio 1:5:1.02 is actually 1:6 for the combined single output rail.
Hope this clarifies.
Good luck in your project, and feel free to post here if you have further questions.
-Youhao
