I have a cheap ring-light that does this. Honestly, as a flash it's pretty lame.
To put it in perspective, a basic 400Ws studio flash dumps its 400J in about 1/800 s. So during the time of the flash it's radiating at around 320kW (ie 320,000W).
Now maybe LEDs are 5 times more efficient, and you only use your flash at -3 stops... you're still at 8kW.