SMART IC in chinese led lamps

[paulc]

I bought one of these just to understand what is that "wonder ic" inside.
I couldn't understand the operation of the IC.
I am attaching the drawing.
Can someone help?

[Seekonk]

I saw this IC discussed once before. Don't think I saved the pdf. It is basically a transistor with an external resistor in the emitter operating as a constant current source with a fixed voltage on the base.  Very simple linear device that will heat up.

[paulc]

Yes, it looks like a dual version of the ON SEMI CC regulator.
I am impressed.
I thought the IC is acting as a fuse instead the missing one in the input. 
Thanks for solving the mystery.