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Help with DIY laser driver

lasersbee

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Pfft.



:p :beer:

Good advice! :beer:
Nice Dummy Load....
Very clean and professional looking wiring.:gj:

Jerry
 

jimmy433

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Im trying to run it at 12v with my power supply but it stops at around 7-8v 800mA

as for the diodes im using 3amp ones with a PRV of 400, but i doubt its that because i reached around 1.5amps with that DIY driver with a dummy load of the same diodes.

you are right though they did heat up very quickly. However i will get higher rated ones and try it out again just to be sure.:thanks:

Im looking to get around a 3.5v drop over the diodes and set the driver to 1.5A for now to get around 5v drop all together, the drop over the diodes are showing correct values and the driver doesnt have a pot, i attached a picture below of one that looks like it, cheers.
 

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paul1598419

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You might have an X-Drive. They don't have a pot, but the one you pictured does. Five diodes should get you the 3.5 volt drop you're looking for. If the 1 ohm is dropping 1.5 volts the driver is set for 1.5 amps. Which diode are you using again? A blue diode from a Ca$io A140 projector would be driven at that current.

Edit: I see you are driving some LPC-836s. They won't survive anything near 1.5 amps. You want no more than 400 mA, probably less. They should survive 370 mA without much trouble.
 
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jimmy433

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oh my bad where is the pot in the picture i attached i cant see it?

im only getting 800mA over the resistor right now but i want to set it to 1.5A

i used the lpc 836 for experimentation with that DIY current limiter driver i constructed, for this driver i will be experimenting with NDG7475's and am trying not to make any mistakes along the way haha

also yes i will be heat sinking the driver :)
 
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paul1598419

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That's not a cheap diode. You want to put that in a good heat sink. It is very inefficient. Are you sure you want your first build to be that diode? You can build your driver and test it out on an M140 diode. Much cheaper and not a huge loss if something goes wrong. Once you have built that one, then do the green. You aren't off to a great start and I'd hate to see you lose it to a simple mistake. If you lose an M140 that's what? $30.00? you can always reuse the driver for the green once you see it work. You can run that driver with two Li-ion batteries too.
 
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jimmy433

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oh god i know, ill be putting it into a 30*30*50 mm heat sink + host module with a fan and will hook a TEC system up on it as well with a temperature control unit, it may be overkill but its better to be safe than sorry plus i have those components lying around so why not.

so where abouts was the pot on that badboy?
 
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paul1598419

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On the opposite side of the board that you posted in #18. You can't see it because of that.
 

jimmy433

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Theres a pic of the opposite side in #10 where abouts should i looking my good man i cant seem to see it?

is it that little hole in between the IC chip pins? because other than that i see nothing
 

paul1598419

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My mistake. It seems there are two versions of the SXD V3 driver. One with a pot and another with set resistors. I made the assumption that you had the one with the pot. Sorry.

BTW, since you are going to be TEC temperature controlling the diode, why not drive it at 2 amps? I would.
 
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jimmy433

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I will end up doing that, i just wanted to set the current to a stable setting and get first light before i start pushing the diode
 

paul1598419

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I guess I don't understand why you felt it necessary to bridge the resistors to get to a higher level on a preset SXD V3 driver. Whoever sold you the driver should have done that for you. By setting the driver to the higher level you can't know what current is is set for when done.


Edit: I know now why this has been so confusing. Diachi mistakenly posted the resistor bridge for the adjustable continuous ground X-Drive. This is an SXD V3, which is a totally different driver and does NOT have the resistor bridge. So, like I said at the beginning of this thread, you need to remove the bridge you put between the resistors. It is not the same as the driver that uses the bridge. Those only have a pot on them.
 
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jimmy433

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I think he was referring to this post http://laserpointerforums.com/f39/x-drive-x-boost-88589.html about 5th picture down on the left, where he would be correct but then again so are you because it seems this SXD V3 has a pot.

As i mentioned the current before i bridged the resistors was 800mA and after it was the same, also i didnt buy this driver it was provided and i had to work out the kinks so i dont really know if it is preset, i assume he got it from ebay from dtr so i messaged him to see if he could help.

But do you really think the driver is preset? if thats so im screwed, luckily i ordered another driver with a pot but it will take a few weeks to get here.
 
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paul1598419

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Any driver without a pot is preset for a specific current and unless you change the current sense resistor, will remain set. I'm glad you ordered a Super X Drive V3 with a pot. That and the other one with a pot that I referenced earlier are the only ones that you can "set" the current on. The Nano Boost Driver has three resistors that can be bridged to get one of three current settings. 275 mA, 500 mA and 1.1 amps. But, it is a totally different type of driver.
 

jimmy433

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Thanks for the help mate saved me a lot of time going back and forth figuring out what was wrong, ill post pics when i get the parts in and get it up and running.
 

paul1598419

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Always glad to help whenever I can. I'll be looking forward to your build when you get it done. :yh:
 

Cyparagon

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1ohm sets the current for 1.25A. If your supply is only rated for 1A, it may be shutting down or using a foldback feature.
 




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