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Advice/opinions for ~2A driver; 9mm 445nm build

aluminous

aluminous

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I want to drive a 9mm 445nm diode (sold by DTR) driven at 1.8A, maybe 2.0A. :D I was first thinking of using a FlexMod P3 since it has plenty of output plus analog modulation, but the FlexMod seems too large for most hosts. I'm now considering a dual driver setup*. I've found that some smaller drivers have fixed currents...
  1. Am I correct in assuming I can safely combine drivers with different currents (say 1.2A and 800mA)?
  2. I'd like to adjust the output intensity (I'm planning a 3-position key+lock switch for off-low-high modes). If I use a fixed current driver, is this still doable/recommended? Especially if my switch is on the size with the battery...
This is my first build, so I apologize I've misunderstood anything. :)


*If I've missed an appropriate ~2A driver that's available somewhere, please let me know-- I'd rather keep it (partially) simple ;)
 





Blord

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Pretty daunting task. First build a 2W laser :)
You can combine two drivers to have higher output. It is the best you equal the load over the drivers like 2x 900mA. But not all drivers can be done like this.
You tell nothing about the battery configuration. The drivers depends on the configuration.

If you want multiple mode the wirings gets complicated. I suggest you keep it single mode and build another laser for smaller output.

Good luck with the build. :beer:
 
DTR

DTR

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You can combine some drivers but not all. Did not see what driver you were talking about. I would not attempt do combine drivers of different types.:)
 
aluminous

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Thanks for the fast replies!

I haven't chosen a battery configuration yet, as I figured it would depend on what driver configuration was possible.

DTR, you mention you have a driver capable of powering the 9mm diode from a single Li-Ion on your website-- it that the "Prewired Modded 1.5A Microboost" or is there a more powerful driver? If I'm using this diode, I'd like to get the most out of it :D.

I also looked at a Mohgasm 1.8A linear driver, but I couldn't find anywhere to buy it, unfortunately...

I'd like to avoid combining drivers, I had read about using dual ben-boosts, as described here http://laserpointerforums.com/f48/wiring-dual-ben-boost-driver-73042.html
 
aluminous

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Blord said:
You are talking all kind of drivers. I suggest you read this, http://laserpointerforums.com/f67/how-laser-diode-drivers-work-explanatory-thread-71513.html
Click to expand...

Wow, you're right. Thanks for that! :yabbem: I found what (I think) would be a reasonable driver: 3A BlitzBuck at Cajunlasers. And this being a buck driver, I imagine I would have a good duty cycle. In that case, it looks like 3x series 3.7V Li-Ion cells be reasonable if I can find a host (I probably have some more reading to do).

I'll probably will wait until another build to try multi-mode, but in general how is this usually done? One thread I saw suggested leaving the pot on the driver accessible to vary the power, but it seems like there would be safer ways.
 
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DTR

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The blitz buck is probably the driver I would go with right now as well for the 9mm diodes. I am not sure how the 1.5A microboost would react to the higher forward voltage of the 9mm diode. It may limit it to less current based the the max current draw of the circuit.:)
 
ARG

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I have two 9mm diodes, and I just ordered two blitz bucks for them. They seem like the best choice because of the efficiency, and you only need one driver for one diode so it's not as costly.
 
benmwv

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Maybe wolf can chime in here and tell us if there is an enable/dim pin on the IC in his driver. If there is its probably connected directly to Vin so you would have to desolder that pin and bend it up so you can attach a wire to it. Then get a small microcontroller, design a circuit, and write some code to make the modes by feeding pwm through that wire.

In a benboost there is a 100k pull up resistor on the EN pin, so you solder a wire to the top right pin of the lm3410 (when the side with 2 pins is facing up) and pull low to modulate it.

Not an easy task for a first build, or for someone inexperienced with electronics.
 
Wolfman29

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I didn't see this!

There is an enable pin. It's the second pin from the left on the bottom (the side opposite the inductor).
 
aluminous

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I just ordered the 9mm diode and BlitzBuck! :)

benmwv said:
Maybe wolf can chime in here and tell us if there is an enable/dim pin on the IC in his driver. If there is its probably connected directly to Vin so you would have to desolder that pin and bend it up so you can attach a wire to it. Then get a small microcontroller, design a circuit, and write some code to make the modes by feeding pwm through that wire.

In a benboost there is a 100k pull up resistor on the EN pin, so you solder a wire to the top right pin of the lm3410 (when the side with 2 pins is facing up) and pull low to modulate it.

Not an easy task for a first build, or for someone inexperienced with electronics.
Click to expand...

Okay, thanks. Hmm... This isn't my first experience with electronics, but that sounds like more than I would trust myself with... I'll have to try this when I know what I'm doing.

One more question, the BlitzBuck is supposedly a "two-cell" solution, and on CajunLasers it says 2x 4.2v cells is enough for a 445nm diode. Does that refer to 3.7v-rated cells that have 4.2 when fully charged? I've seen many 3.7v cells for sale, but not too many 4.2v ones...
 
benmwv

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Yeah, the 3.7v and 4.2v cells are the same thing.

I don't know what host you plan on using but for a build this powerful you should probably 18650 size host and power it with two 18350 batteries. Of course bigger would be better but most 18650 host should be adequate.

I agree, for a first build it's best to keep it simple ;)
 
Wolfman29

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Yeah, the BlitzBuck works with any voltage amount more than approximately 20% more than the output voltage. Meaning that it will work with any voltage over 5.5V input, as long as it's under 25V output.
 
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