My intent is to use my arduino to control some LEDs via PWM. I have the PWM signal part down but Im having trouble understanding how to make the driver circuit. I want to use 12v from a car and the LEDs foward voltage is 3.7v @ 700mA. If I use the circuit below I wouldnt be able to put more than 3 LEDs in series before exceeding my input voltage. (3.7v x 3=11.1 voltage drop) So if I wanted to use 9 LEDs for example could I make 3 driver circuits with 3 LEDs each and power them all from the same 12v source? Does this sound right or am I completely off base?