Quick Question: Laser Driver

[Vanguard]

Hey everyone, i'm after a laser diode driver that i can use to test virtually any laser diode from a DVD or CD burner, i have tried an LM317 constant current based design, but don't seem to be having any luck with those. Can anyone recommend a circuit that i can build myself?

 

[Ace82]

The LM317 seems to have given me problems as well. As far as other driver builds, read up on some of the boards here and you might find something, otherwise I suggest to bite the bullet and buy one of these rkcstr drivers, or he offers kits if you want to build your own or modify them in any way.

http://www.laserpointerforums.com/forums/YaBB.pl?num=1206947255/0#0

 

[Vanguard]

thanks dude, i think the LM317 driver's problem is due to the fact that the output voltage is only 1.25v in constant current mode, i will look into the rkcstr drivers.

 

[rog8811]

i think the LM317 driver's problem is due to the fact that the output voltage is only 1.25

Not so, the 1.25v is just the reference voltage. Using the LM317 as a CC circuit all you need to do is attach a heatsink and supply it with 9v to 12v and it will drive any LD you are likely to come across.

With the pot you will adjust the mw and the voltage will sort itself out.....
The LM317 has been my circuit of choice in at least 15 lasers and is my bench supply that puts first power to everything I build.

Correctly built and tested it is a very good circuit for this kind of work.

Regards rog8811

 

[Mohrenberg]

well.....i guess you could use a fixed output rckstr driver at like 150ma, this is low enough that it shouldn't hurt most red diodes and you should get get atleast 100mw........since your only testing them....

 

[billg519]

My bench laser supply is based on an LM350, which is the 3a version of the LM317. I provide 10v input and can control output current to the diode from 0-3a. LM317 style drivers need about 3 volts more than the laser diode drops at full power. So, a 3v red diode would need at least 6v input to the LM317. A 5v bluray would need 8v minimum to the LM317. Any less and the regulator is at risk of dropping out of regulation. Also, the current drawn must not drop the battery voltage down below this requirement. Like Rog8811, I have built many successful lasers based on LM317 (or 350, 338) style current regulators. The rckstar, drlava, and like drivers are awesome because of their small size. They are the way to go if you don't want to build, test, and troubleshoot your own driver.

 

[Hemlock_Mike]

The LM317 chip and it's related uses has been around for over 20 years. It is tested and proven. The CC circuit which DDL provided is a simple modification to the original National Semiconductor circuit published back then.

Build it -- Understand it -- It works.

Mike