http://www.aliexpress.com/store/prod...537290497.html
I won't vouch for this but it appears to be a control IC for a PWM power supply. If it's blown there may be a power MOSFET that is also toast. And maybe a flyback diode as well.
These power supplies aren't trivial to repair. I'd suggest, if practical, remove the power supply and substitute another. If it's only got one output voltage that would be easy enough.