Hiemal
0
- Joined
- Dec 27, 2011
- Messages
- 1,443
- Points
- 63
I've recently been trying to figure out how to run my laser diodes on 3 - 4.5 volts...
Using the super common LM317, the laser wouldn't be very bright as it typically drops around 3 volts at 250 mA.
I've tried several different methods of driving; from using shunt regulators, to discrete op amp and transistors, but nothing worked. I was getting frustrated...And I didn't want to deal with switch mode regulators!
But, then I finally found something that worked.
http://www.fairchildsemi.com/ds/KA/KA278RA05C.pdf
This IC, solved all of my problems. It drops only .5 volts!
Here's the exact schematic of what I used.
It works perfectly. There's no difference in brightness from 4.5 volts to 9 volts, which means it's doing its job. However, at 3 volts, the diode intensity drops considerably, (might need more current; it still lases, though) and at 1.5 volts it refuses to even turn on.
Thanks for reading, and I hope this driver works well for others who decide to use it.
Using the super common LM317, the laser wouldn't be very bright as it typically drops around 3 volts at 250 mA.
I've tried several different methods of driving; from using shunt regulators, to discrete op amp and transistors, but nothing worked. I was getting frustrated...And I didn't want to deal with switch mode regulators!
But, then I finally found something that worked.
http://www.fairchildsemi.com/ds/KA/KA278RA05C.pdf
This IC, solved all of my problems. It drops only .5 volts!
Here's the exact schematic of what I used.
It works perfectly. There's no difference in brightness from 4.5 volts to 9 volts, which means it's doing its job. However, at 3 volts, the diode intensity drops considerably, (might need more current; it still lases, though) and at 1.5 volts it refuses to even turn on.
Thanks for reading, and I hope this driver works well for others who decide to use it.
Last edited:
