In several projects so far, I have been using old "fashioned" transformer based power supplies. However, this time around I want to use a switching mode power supply. The supply will be used to power some 5V micro controller and supporting electronics. The power requirements are equivelent to that of a old usb phone charger (which for several reasons is not going to be used.)
After some research on the internet I found a very neat tool by NXP, which helps with most of the complicated mathematics involved: http://nxp.transim.com/fb/design.aspx So far i have been using the default specifications (universal mains, 5V, 5W, integrated FET, TEA1721)
Unfortunately i get stuck at the part where i have to choose the transformer (the bottom 3 choices from the "design" tab).
For instance, i want to use the following transformer: http://nl.farnell.com/bi-technologies-tt-electronics/hm42-10001lftr/transformer-gate-drive-300uh/dp/2192063 The tool proceeds to ask questions such as: Winding ratio, primary inductance and last asks the specific transformer you use.
The datasheet of the transformer(sorry, cant post more than 2 links) i was planning to use (and also several other transformers out there) do not answer there questions. Because of this I get the feeling that when designing a SMPS also a specific transformer is designed.
So the above boils down to: where can I find the data required to completely fill out the design tool?
Any help is much appreciated, thanks in advance!
Kind Regards, Victor