Using a DealExtreme driver board to power a laser

[spectral532]

Is it possible to use one of the led drivers from DealExtreme to power a laser? I am looking for cheap driver to power a red LOC or a PHR-803T from a single Li-ion battery.

In particular, I have been looking at SKU 7882 and SKU 15880. Both are capable of boosting voltage, and SKU 15880 seems to have boost/buck capability.

I'm not sure how good the regulation is on these though, maybe someone here has had experience using these boards?

 

[LiveRock]

I think you need a custom current driver...

 

[HIMNL9]

Those drivers are multi-mode drivers (read the descriptions), that means they also control flashing and different currents ..... i don't think they are good for lasers (at least if you don't want all those functions intentionally )

 

[spectral532]

I think you need a custom current driver...

I think the output on these drivers are adjustable. SKU 7882 has a potentiometer you can adjust. While I havent verified it yet, I think you can swap some sense resistors to set the current on SKU 15880

Those drivers are multi-mode drivers (read the descriptions), that means they also control flashing and different currents ..... i don't think they are good for lasers (at least if you don't want all those functions intentionally )

I dont mind the multi-mode , most can be disabled by soldering a few jumpers on the board. Besides, having a low-medium-high power option would be nice.

 

[sightfx]

There is a solder jumper you can make to make it a constant mode driver. I used this driver for a short time. I have powered a PHR with it but didn't try any modes.


Edit: It is adjustable.

 

[Deleted member 8382]

The second one is not adjustable, the first one is intended to output 3.5 amps. I would never try to power such a sensible component like a laser diode with this. Also, look at the comments, they say they take a huge ammount of power from batteries and that the efficiency is under 50%!

 

[sightfx]

I just pulled my SKU7882 off the shelf to test it again because it was about 9 months ago when I started experimented with it. with a 1.5V input it will draw 380ma from source and supply 80ma at 4.8V to the diode. That puts efficiency at 65% which literally sucks


cheers :beer:

Ryan

 

[spectral532]

The second one is not adjustable, the first one is intended to output 3.5 amps. I would never try to power such a sensible component like a laser diode with this. Also, look at the comments, they say they take a huge ammount of power from batteries and that the efficiency is under 50%!

I think that the 15880 may be adjustable. I've read about some mods where a person increased the output of this particular driver, so I would imagine I would be able to decrease it also. Additionally, the 50% efficiency you quoted is when the driver is boosting from 1.2v volts. When it's boosting from 1.2v, there is going to be a fairly large Vin/Vout differential, so I wouldn't expect efficiency to be too high. Besides, I'm planning on using a 3.7v Li-ion, so efficiency will probably be higher than when using 1.2v.

I just pulled my SKU7882 off the shelf to test it again because it was about 9 months ago when I started experimented with it. with a 1.5V input it will draw 380ma from source and supply 80ma at 4.8V to the diode. That puts efficiency at 65% which literally sucks


cheers :beer:

Ryan

Personally, I dont find 65% all that bad. It's better than the ~50% efficiency I'm getting with the LM317. Besides, when it's boosting 1.5v all the way up to 4.8v, I dont expect that great of an efficiency anyway. Most boost drivers I have read about decrease in efficiency the greater the difference between Vin and Vout, and the 7882 appears to be no exception. I plan on using a 3.7v Li-ion with the driver anyway, so efficiency should be much higher.

 

[sightfx]

I experimented with a dummy load and put 3V in. The current was >300ma. I think that is because this is a voltage regulated driver and the dummy load draws that much current. All I can say is use it at you own risk and don't risk anything expensive.


-Ryan

 

[spectral532]

After reading a bit more about the 7882 driver board, it does appear to be voltage regulated. Plus, the 15880 seems to have poorer regulation that I had previously thought. So neither of these boards looks too promising for driving LDs. But even then, I might just end up buying a few of these circuit boards and run some tests on them. If I ever get around to doing that I'll report back with the results.