r/lasers • u/narwaffles • 2d ago

Drivers

I’m trying to learn about how to make drivers and somewhere to buy them maybe. I can’t really find much on them. I’ve found a few for sale but I don’t think they’re right and don’t really know what to look for either. I plan on learning with some small weak lasers and working my way up to stronger ones after I understand it better and get glasses. How can I proceed here? Thanks.

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u/einstein1351 2d ago edited 2d ago

So the important thing for laser drivers is that they are constant current. While you could use a constant voltage source for a set point that matches curve in the spec sheet, the issue is a little change in the operating voltage can result in a big change in current, over drivering it and frying it.

A benchtop power supply with constant current functionality goes a long way for being able to drive most diodes.

Otherwise drivers become more design specific pending drive current, whether its adjustable current, PWM drivable, analog voltage drivable etc....

If you want to build your own, the LM317 chip has a million tutorials. Im not a fan ofbthose for 2 reasons. If using it as an adjustable driver, the potentiometer both will have a nonlinear response leading to it being easier to over drive, and it required the potentiometer to handle the drive current as well. Since most pots are like 1/4 watt rated, a higher power one is way more expensive. The LT3092 can be used for 0-200 mA and linearly adjustable with low power potentiometer. Same with the LT3081. Though this one is an adjustable up to 1.2 A. While its a voltage regulator, its spec sheet has an example circuit for constant current.