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how to drive a low/high power switchable 445nm?

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lhenderson

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Hi Everyone,

I'm new to the forum, but I've searched and not found a good answer. I'd like to build a 445nm laser (probably with an M140 that's switchable between about 200ma and 1.7A so that I can have a "safe" (ok, somewhat more safe) and a burning laser in one unit. I've read threads about pairing up drivers, but they always seem to be matching outputs for higher power.

I guess the simple question is: can two drivers be wired to the LD, but only have one active at a time (ie: switch one of the battery connections between the two drivers)? Would the unpowered driver circuitry interfere with the operation of the powered driver?

If anyone has any other suggestions or ideas, I'd love to hear them.
 





You can have a burning laser with a single 1A driver easily, and all you'll need to do is solder the M140 module to the driver!

I believe M140's power depend 1>1 with the driver, so if you have 1.5A, you'll output ~1.5W, depending on your diode's efficiency!
 
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Your best bet is to buy JAD kit (just add diode) with a preinstalled driver and heatsink and just add the m-140 module.
 
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Thanks for the responses, RedDart, but you seem to have missed the point. I'd like to be able to change the output current from about 200ma to about 1.7A with a switch. That either requires two drivers, or one where the current is switchable. Granted, just building a burning laser is easy with the available drivers.
 
OR you could go hardcore and buy a host with a heatsink that has 2 module slots and just basically go for 2 lasers in 1, with 2 switches :) (They would run off the same batteries)

Kind of what I was saying; although it would be much nicer.

2-in-1-LED-Laser-Pointer-Flashlight-Keychain-Silver_2.jpg
 
lhenderson said:
I'd like to be able to change the output current from about 200ma to about 1.7A with a switch. That either requires two drivers, or one where the current is switchable.
Click to expand...

Looks like you answered your own question. :)
 
I've seen people modify flashlight driver to have modes. Never done it my self but it can be done.
 
I have actually been trying to eliminate modes on my 5 mode lights and leave just hi-lo because strobe/sos gets annoying quick... but that is a different topic. If it was me I would just use two drivers with an dpdt switch.
 
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There is lot's of LED drivers that has different modes on DX. Just search for some of them there.
 
This is much easier than you think. I use a buck driver for my build. Normally the laser uses two 3.7V 18350 cells for full output. But when you use a single 3.7V 18650 for the same laser the output drops to 100-200mW. One cell doesn't provide enough voltage for the buck driver to regulate and the output is severely underpowered.

This trick doesn't work for a linear driver because the voltage drop of the linear driver is much higher than a buck driver. There are exceptions like the ST driver.
 
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Thanks for all the replies. That gives me some info to digest. I was looking at the x-drive buck drivers. Do they have a trim pot to set the current level? If so, could one replace the pot with 2 fixed resistors and a dpst switch?
 
i'm with blord on this. just use a buck driver and go to one cell for "safer" power output. no muss no fuss
 
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