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1.8 Ampere Driver (~9Vin)

yesthisissean

yesthisissean

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So I want to build a DDL/LM317 style current driver for a M140 laser diode, but the LM317 build only goes up to 1.5 Amperes :(

I want to find out how to build a 1.8A current driver that can use 9V....any help I will be thankful for
 





Kind of redundant since your last thread mentions you have decided to use the L200 driver.


As for the driver...
I saw that the LM317 Constant Current Driver was good for outputs up to 1.5A. This diode requires an amperage of 1.2A-1.8A, so the LM317 will be no good for this diode (I know you can set up the regulator with a heatsink, but I prefer not to :3).
Click to expand...

If you want to run your m140 above 1A and you're preferring not to heatsink it, the driver would always overheat and either the thermal shutdown will occur or your whole laser will start blinking within seconds after turning it on..

My advice, Save yourself trouble and get the diode with a pre-installed X-Drive if you havent ordered yet, otherwise order a new buck driver..

If not, the better alternative to it would be LM1085/1084 if you can get one , use 0.7Ohm resistor and 16v 10up caps on input and output , make it like a ddl , Do heatsink it otherwise read the above once again..
 
You won't be running any linear driver at 1.8A without heatsinking, that's for sure.
 
I know that the L200 is a possibility, but I've also heard that you can set up the LM317 in parallel with another LM317. I could not find any more information about doing this...

As for the L200 voltage regulator, it is simply too complicated to impliment a viable circuit just to regulate the current. The regulator has too many capabilities and ends up being a waste of time.

but yeah, im currently (haha) trying to figure out that two LM317 parallel circuit right now



sinner said:
Kind of redundant since your last thread mentions you have decided to use the L200 driver.




If you want to run your m140 above 1A and you're preferring not to heatsink it, the driver would always overheat and either the thermal shutdown will occur or your whole laser will start blinking within seconds after turning it on..

My advice, Save yourself trouble and get the diode with a pre-installed X-Drive if you havent ordered yet, otherwise order a new buck driver..

If not, the better alternative to it would be LM1085/1084 if you can get one , use 0.7Ohm resistor and 16v 10up caps on input and output , make it like a ddl , Do heatsink it otherwise read the above once again..
Click to expand...
 
Assuming your supply voltage of 9v and a diode forward voltage of 4.25v, the regulator will be dissipating 8.55W of heat to run the diode at 1.8A.

With no heatsinking the regulator will quickly reach thermal shutdown temperature and your laser will dim/flash as the regulator protects itself from turning into a mess of burnt plastic and silicon. No heatsink is probably doable at 1W, but at 8.55W not even close
 
SKeeZ said:
anyone know if parrallel 317's would work?
Click to expand...

yep, here it is with the output of 2.301A

VULk3Lt.png







and this one dialed in at 1.755A

HknnltZ.png
 
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