We don't currently recommend using our TopSwitch product family for LED applications. They can be used but the secondary side feedback circuitry can be complicated to design as there needs to be two sections, a CV section and a CC section. Handling the transition between the two modes can be tricky to design.


We do however, have an entire product line devoted to making LED driver power supply design as simple as possible. For higher power LED designs, power factor starts becoming an important regulatory requirement. Our LED products have features built-in to address power factor correction. With our TopSwitch products, you can put together a power factor corrected design (this relies on a very very small bulk cap) but again, it's more complicated to do.


With these features designed into our LED products, this means less design work for your team, less debugging, less components, lower product cost, higher reliability, etc.


For lower power & non-isolated designs, check out our LinkSwitch-PL family:
http://www.powerint.com/en/products/linkswitch-family/linkswitch-pl


For higher power and isolated designs, please see our LinkSwitch-PH product family:
http://www.powerint.com/en/products/linkswitch-family/linkswitch-ph


If you're absolutely dead-set on using a TopSwitch product for your LED driver, please see some of the following Reference Designs:
http://www.powerint.com/sites/default/files/PDFFiles/der168.pdf
http://www.powerint.com/sites/default/files/PDFFiles/di136.pdf
http://www.powerint.com/sites/default/files/PDFFiles/der100.pdf


I'm also attaching two Design Notes published by Power Integrations. One covers TopSwitch PFC applications and the other covers CV/CC feedback circuits that can be used with TopSwitch controllers.


One last thing, I put together a quick LinkSwitch-PH design using our PI Expert software. It's a universal input, 35V, 1.4A output LED driver. You can open it using our software and it will have the transformer diagrams, major component values, etc.


I hope this helps answer your question. If you need further assistance, please let me know.

-The Traveler