High current diode driver

• Jul 10, 2008

• #1

GooeyGus

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Hi guys, I'm in need of some help.

I need to build a constant current driver capable of driving to around 3A. It will be powered by a DC adapter @ 12v, but I can get one with a lower input voltage if needed.

basically the driver I use now to test all my diodes is an LM317 built into an easy to use case that plugs into the wall via the 12v adapter. The problem is now I am playing with some much higher power c-mount diodes and I need to be able to supply more than 1.5A of current (the limit for the LM317)

Any ideas??

Thanks in advance!

 

• Jul 10, 2008

• #2

FireMyLaser

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Try the LM350, it can take up to 3A and is just like the LM317.

 

• Jul 10, 2008

• #3

rkcstr

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Not sure if it's doable (or recommended), but you may be able to parallel two LM317 circuits to get 3A capability.  You'll need some good heatsinking for all that, though.

EDIT: I deleted my double-post.

 

• Jul 10, 2008

• #4

sk8er4514

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woah, deja vu

 

• Jul 10, 2008

• #5

jamilm9

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sk8er4514 said:

woah, deja vu

Click to expand...

yeah ;D deja vu

 

• Jul 11, 2008

• #6

pocketfluff

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2 or 3 7135 boards off a 5v adaptor?

 

• Jul 11, 2008

• #7

J

J_Dogg

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A old computer PSU would be a good place to get a alum heat sink for LM317's

 

• Jul 11, 2008

• #8

GooeyGus

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J_Dogg said:

A old computer PSU would be a good place to get a alum heat sink for LM317's

Click to expand...

I tried heat sinking it and all, I even had my lm317 TEC cooled ;D but even with the cooling the most it would crank out is 1.6A and then fall on its face.

 

• Jul 11, 2008

• #9

GooeyGus

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pocketfluff said:

2 or 3 7135 boards off a 5v adaptor?

Click to expand...

details?

 

• Jul 11, 2008

• #10

pocketfluff

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GooeyGus said:

[quote author=pocketfluff link=1215697091/0#6 date=1215738194]2 or 3 7135 boards off a 5v adaptor?

Click to expand...

details?[/quote]

Search "amc7135" into dealextreme. There are ready to go boards that supply 1.4A. Nice and simple

 

• Jul 11, 2008

• #11

rkcstr

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It looks like they're just connecting those chips in parallel to get 1400mA, so you could probably parallel two of those 1400mA boards to get ~2.8A? I think gazoo has used these extensively and has a thread somewhere about them (but I'm too lazy to look for it now ).

 

• Jul 11, 2008

• #12

W

woop

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just put some lm317 circuits in parallel (if you have some lm317's lying around)