I am trying to develop a circuit for a Motorcycle Turn signal. Want to generate a constant 300ma current through 5 LED's. Then I can flash them with an Arduino. I've attached my schematic, and some measurements I made with a circuit I bread-boarded. With a 10 ohm resistance (actually 8 Resistors in series) I was getting around 61mA through the LED's. I then moved the ground point through the series resistance (effectivly lowering resistance) and recorded the current (keeping Vs = 12.99V). I saw that with R=2.9ohm, I-LED = 192mA, and with R=1.2ohm I-LED = 560ma.
If this relationship is linear, I am guessing a Resistance of 2.4Ohm, should give me the 300mA I desire.
Can anyone verify if I am on the right track, or am I missing something here. The LED's are CREE and the FET info is on the attached schematic. Any help finding/verifying the components I need for this would be appreciated.
