Switching
Power Magazine
This link takes you to the subscription page. There are a bunch
of online articles that are available once you subscribe (which is
free).
Ridley Engineering Design Tips
A bunch of real world design tips that are well worth reading. Switch Mode
Power Supplies
This site has a bunch of different configurations, though the
explainations are not as good as the Knowledge Base above.
Power Electoinics Textbook Online
This is an entire textbook and it is online for you to download or
browse.