Other Parts Discussed in Thread: TL431, UCC256404, UCC28056, PMP22087
This might be a useful addition you could add to your Excel Spreadsheet UCC25640x Design Calculator and others.
I want to use the standard TL431 type feedback control to a UCC256404 design. I would assume that most designers would do the same.
In my case, I want values for a 5.0V output, rather than the 12V output values shown.
From the circuit values shown in the application notes, I can't determine what Opto current you are targeting.
What might it be?
While in other designs, a 1k resistor is placed across the OPTO LED, the UCC256404 application schematic shows 3k. No doubt there is a reason for this.
Furthermore, to provide appropriate RC values for compensation would ensure designers are implementing the UCC25640x optimally.
To have an additional Excel page with a TL431 value calculator might be very useful.
The TI Excel spreadsheets I am using (UCC28056 and UCC256404) are excellent and I will trust what it suggests. To extend this to the TL431 would complete the package.