Circuit has been tested with an IRFZ44N as the MOSFET, and a 2N2222 as the BJT. The 1 ohm resistor should be fairly chunky, about 10 watts is good. This circuit can be used to drive a 1W LED with a 4.7 ohm resistor in place of the 1 ohm.
Tested with CXA1507 21V @ 24V into the circuit, about 550mA was taken by the LED.
