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Newbie trying to get a laser diode working

JoyBike

New member
Joined
Jan 27, 2024
Messages
3
Points
1
Hi, I'm just getting into lasers and recently purchased a laser diode to make a laser to engrave wood with. It was only after I purchased it that I realized that getting it running would be a lot more complex than just hooking the diode up to the specified voltage and amperage. I've done a lot of research but still can't quite grasp what I need so I'm hoping you guys will be able to help me out. The specifications for my diode are as follows,
Features:
Wavelength: 850nm (±5nm)
Output power: 2.3W
Threshold current: 0.2A
Forward current: 2.5-3.6A
Forward voltage: 1.7V-2.2V
I saw a post that said you can just use an amc7135 to create a simple cheap constant current driver. But that was for a dvd burning laser and mine is a bit more powerful. As far as I know, the amparage of the amc7135 is 350mah. I was wondering if I could just wire 9 amc7135s in series for the 3 amps I plan to put in. And then as for power, I'm trying to make it handheld to be easier to engrave, and I'm struggling to find the best way to supply my diode and driver with 2v 3a.
If you guys have any tips for my design or better ideas I'd be glad to hear as you are all definitely more experienced than I am. Thanks in advance!
 





Joined
Jul 10, 2015
Messages
9,903
Points
113
You NEED laser safety goggles to attenuate the wavelength you will be working with.
Be very careful with NIR lasers, you can blind yourself before you know what has happened.


 

JoyBike

New member
Joined
Jan 27, 2024
Messages
3
Points
1
You NEED laser safety goggles to attenuate the wavelength you will be working with.
Be very careful with NIR lasers, you can blind yourself before you know what has happened.
Yeah, I already did some research and found out that 850nm is NIR which is basically invisible so I'll be taking proper safety precautions when using it. If I can get to using it. As an update, my plan for powering it so far is a 3.7v 18650 cell as it can provide the current needed and then using a bucky converter to drop the voltage to 2v. Thanks for the concern
 
Joined
Sep 16, 2007
Messages
3,658
Points
113
The AMC 7135 drivers will work but they must be wired in parallel to increase current and keep voltage the same.
These regulators get hot, so they should be attached to a heatsink. They also have a relatively high voltage sag, so your power supply should be able to compensate for the drop in voltage once it's supplying power to the load.
I've used this kind of setup but it's not worth the trouble in my opinion. Your money and time is better spent on a proper constant current regulator.

Browse the forum a bit and you may find that there are other options for driving laser diodes more efficiently.
For example, you can probably find an inexpensive laser driver meant for 808 nm laser diodes on eBay. Just be mindful of the case polarity of your diode and the polarity of the driver. 808 nm diodes are typically case +.

As was already suggested, please use proper safety eyewear when operating lasers.
 

JoyBike

New member
Joined
Jan 27, 2024
Messages
3
Points
1
The AMC 7135 drivers will work but they must be wired in parallel to increase current and keep voltage the same.
These regulators get hot, so they should be attached to a heatsink. They also have a relatively high voltage sag, so your power supply should be able to compensate for the drop in voltage once it's supplying power to the load.
I've used this kind of setup but it's not worth the trouble in my opinion. Your money and time is better spent on a proper constant current regulator.

Browse the forum a bit and you may find that there are other options for driving laser diodes more efficiently.
For example, you can probably find an inexpensive laser driver meant for 808 nm laser diodes on eBay. Just be mindful of the case polarity of your diode and the polarity of the driver. 808 nm diodes are typically case +.

As was already suggested, please use proper safety eyewear when operating lasers.
Hey thanks for the response, I've already looked on eBay and while there are drivers that can do 850nm none of them can do the voltage or current I want, most have a voltage of 3-5 (I'm shooting for 2v) And a max current of around 500mah (I'm shooting for 3a). If you know of one that can do what I'm looking for that would be awesome.
 




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