W
Hey hey....
I need to drive a fiber coupled 50mW, 520nm diode from a 12V DC source. I'll probably only need 20mW out the end of the fiber but want the capability to go higher depending on further coupling losses.
For the driver, I have to drop voltage to 6.5V-7V and then want to regulate the current from 140mA (minimum threshold) to 350mA to control the power. The specifications sheet calls out a max of 7.5V at 400mA.
I originally made a quick breadboard with two LM317 in series to drop the voltage and then control the current. While the circuit worked well on the DC power supply I was using, both regulators rapidly became quite toasty (duh)!
I'm looking to now redesign it as a pcb with a LT8606 (switching regulator) to drop voltage and put out 350mA max followed by a LM317 to regulate current. I currently have it designed with space for a 5W heat sink attached to the LM317.
Does this sound like a reasonable approach to drive this diode while minimizing heat output? The end result will most likely go into an aluminum/plastic bud box type closure.
Recap:
Power in: 12V DC
Power out: 6.5V @ 150-400mA
Board mounted in relatively small enclosed container.
https://imgur.com/a/L8XflN5 - Schematic
I need to drive a fiber coupled 50mW, 520nm diode from a 12V DC source. I'll probably only need 20mW out the end of the fiber but want the capability to go higher depending on further coupling losses.
For the driver, I have to drop voltage to 6.5V-7V and then want to regulate the current from 140mA (minimum threshold) to 350mA to control the power. The specifications sheet calls out a max of 7.5V at 400mA.
I originally made a quick breadboard with two LM317 in series to drop the voltage and then control the current. While the circuit worked well on the DC power supply I was using, both regulators rapidly became quite toasty (duh)!
I'm looking to now redesign it as a pcb with a LT8606 (switching regulator) to drop voltage and put out 350mA max followed by a LM317 to regulate current. I currently have it designed with space for a 5W heat sink attached to the LM317.
Does this sound like a reasonable approach to drive this diode while minimizing heat output? The end result will most likely go into an aluminum/plastic bud box type closure.
Recap:
Power in: 12V DC
Power out: 6.5V @ 150-400mA
Board mounted in relatively small enclosed container.
https://imgur.com/a/L8XflN5 - Schematic