[time-nuts] Hi Power LED Light power supply...

[lists at lazygranch.com]

If you take your garden variety boost converter and place a resistor as the load, the current in the inductor is regulated. (Current is vreference over this resistor value.) All these dedicated LED drive chips do is reduce the voltage across the resistor to improve efficiency. In addition, they might have  an overvoltage protection scheme. If for some reason the load, namely the LED string, is removed, the boost converter will self destruct. Unlikely to happen if everything is soldered together, but LEDs are external, and possibly connection can get loose.