Found the reference design PMP9041, witch is more or less what I wated specification wize, but I did not find enough info about the design and the Transfomer.
I have tried to put the design in Webbench, but the program only allows 24V and 0.5A output (12W). In the TI-listings, there seems to be a limit of 25W designing with this chip? The reference design in PMP9041 is a 40W design, so why the limitation of only 12W in Webbench?
I am not an everyday power supply engineer so I havn't gained the experience to know the right tradeoffs doing these kind of designs. I think it is a great idea with reference designs but I would wish for a document describing the design and tradeoffs made to get to values given in the schematics. I think it would be a great way to learn things as well.
In the case of the PMP9041 the primary inductance is given in the BOM as 180uH, this seems to be a very low value to me. When I try to create a design with the same design goal I end upp with at least a three times higher primary inductance. Is it the tradeoff between core-, winding- and swiching-losses that gives such a low inductance?
Kind regards, Per