DX 5mW red laser driver. Possible use for violet?

[leukoplast]

EDIT: Just to clarify so the thread doesnt get moved to the red laser section, this does have to do with violet lasers...its just a long read  ;D



I have just recently started to get into the whole DIY stuff with violet lasers.  I must admit, its very interesting and a great learning experience.  I got myself some rkcstr drivers, rkcstr test load, soldering tools, multimeter etc etc and am even building my first project.  

Well, In Dave's FS thread for the 635nm 5mW diodes I asked if it was possible to use the DX driver that is used their their 5mW reds for these diodes since I have a few lying around that I got many months ago. He responded that he had never tested them before.   So I figured I would give my rkcstr test load a whirl and see how many mA's these drivers were putting out, just for curiosity's sake.  

I haven't done any serious throughout testing yet, but the results for what I have done made me wonder.

The driver connected to the rkcstr test load with the RED option selected using a single lithium rechargeable that was at 3.91 volts at the time, gave me a reading of 110mA.   110mA??  How come the reds in the DX build require so much power for only 5mW or less output?

I then switched the option to BLU and connected the same single lithium battery.  I got .006mA...obviously it needs more volts.  So I put in two of those batteries, volts were now about 7.8 for the two.  I initially got a reading of 168mA, but I am using tiny 10220 batteries with only 100mAh each, so based on that draw, as I was reading this power the mA's started dropping fast.  About every few seconds it would drop one mA (I didn't hold this for very long, maybe 10-15 seconds at best).

I then tried this with 2 of my Surefire lithium 3.0V batteries (which were 5.79V for the two) I got a reading of 128mA with the BLU option selected.

I am not sure what to think of this, I always figured these little drivers were putting out 10-15mA at best for the red 5mW diodes, and I had no idea they were capable of pushing out so much mA.   Obviously any voltage increase seems to jump the mA output greatly.  When I get home I want to test this out on 100% fresh lithium rechargables with a decent capacity.  Hopefully I can get a good solid reading with about 8.2 volts and see where the resting mA output is with higher capacity batteries on full voltage.

But this got me wondering, lets say one of these drivers levels out at about 185-190mA with two fully charged lithium rechargables, it sure would be one heck of a cheap way to get a driver to use with a powerful violet (or even a PHR if you make sure to not go above a certain voltage, like 6 which would probably be about 135-140mA).   I mean DX sells the complete modules for less than $5.    I'm sure everybody probably already knows about these drivers, but I found this to be very interesting and possible cheap way to get fixed output drivers.  The neat thing is they are so small (~7x9).   If only they had a adjustable pot  

 

[leukoplast]

Re: DX 5mW red laser driver. Possible use for viol

Come on, anybody? All I need to know is if its ok to use one of these drivers with a violet. Because maybe even if the mA is right and voltage..there is probably something else I am not aware of...I know some of you must have tried this?

I would try it, but I only have 2 diodes...I don't want to ruin them when I know somebody else has tried this.

 

[dr-ebert]

Re: DX 5mW red laser driver. Possible use for viol

Are you still here?

As I've already said in Daguins thread, I think it's rather unlikely that the DX "drivers" actually are constant-current drivers of any design (like the dr-lava FlexDriver, which is a "boost" circuit, meaning it can produce an output voltage that is higher than the input voltage [DC-DC-converter], or a normal linear driver like the rckstr or the DDL/LM317 one, which needs an input voltage that is at least ~2V higher than the output voltage). It looks more like some circuitry involving resistors and maybe diodes/zener diodes that only produces an approximately constant current giving a certain input voltage and a certain diode type (=output voltage). On the other hand, you may simply be operating the driver outside of its capabilities (too high/too low input voltage or output V requirements, currents...)

One could only decide that by getting a fuller set of V/I-curves which would require an adjustable lab power supply and an adjustable test load (a simple potentiometer would be a sufficient starting point); getting a circuit diagram might also help, even if you don't know whether that little black thingy is a resistor or a capacitor (let alone their values); just seeing how they are hooked up might give a clue.