jorgealdo
Junior Member level 1
I am trying to develop a small FSO using the computer serial port and a luxeon rebel LED.
While i am very confident about the receiver design, i am still struggling with the transmitter :
The working is simple :
LM317 is configured as a constant current source.
MOSFETS Q3 and Q4 switchs between two loads :
The LED and a resistor.
(When LED is on, the resistor is off and vice versa).
Well, i made this that way to avoid having the LM317 "sensing" the switching on and off of the real load (LED) by a single MOSFET (Two mosfets and two similar loads should make the LM317 not have to adapt fast).
My question is :
Is this really needed ?
Would this really work ?
And if the circuit is indeed correct, what is the best MOSFET for the task ?
I would want 10Mhz switching just to be safe. (Current is 0.350mA for the luxeon and voltage 16V to be safe)
While i am very confident about the receiver design, i am still struggling with the transmitter :
The working is simple :
LM317 is configured as a constant current source.
MOSFETS Q3 and Q4 switchs between two loads :
The LED and a resistor.
(When LED is on, the resistor is off and vice versa).
Well, i made this that way to avoid having the LM317 "sensing" the switching on and off of the real load (LED) by a single MOSFET (Two mosfets and two similar loads should make the LM317 not have to adapt fast).
My question is :
Is this really needed ?
Would this really work ?
And if the circuit is indeed correct, what is the best MOSFET for the task ?
I would want 10Mhz switching just to be safe. (Current is 0.350mA for the luxeon and voltage 16V to be safe)