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Jib77 Driver?

Wolfman29

Wolfman29

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Hey guys.

I just got my two jib77 1.3A (supposedly) drivers in the mail....

I hooked one of them up to two 14500s, and I was getting 1.5-1.6A of power out of it. Not sure if that's even *safe* for a 445... is it?

I was hoping to only 1.3A, but oh well. As long as it doesn't kill my diode....

Anyone know why it may be getting so much power, anyway?

Could it not really be giving off that much, and it just be my testload that is overheating (like the diodes or something)?

Thanks.
 





weidmark

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I've been pushing them to 1.8A without issues. 1.5-1.6 should be fine as long as you are okay with it. Just make sure you heatsink the drivers
 
Wolfman29

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Alright. I will just have to watch the duty-cycle, I suppose.

Wish me luck! I already LED'd a 445 last night (failed attempt to make a driver... I didn't notice the spike in current on start-up. Whoops).
 
weidmark

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Yep :). Make sure you touch those output wires together just before soldering them to the diode.
 
Wolfman29

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Oh, hey, just a quick question: Are there any good substitutes to thermal adhesive? I don't have any right now... and I kind of want to get this laser put together. I have no other means of sticking a heatsink to my driver besides by using thermal compound from radioshack. Should I just thermal-compoundly stick some aluminum to my driver and then put some heat-shrink-tubing around it or something?
 
Wolfman29

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Figured out a better solution: put Arctic silver down, then just stick superglue around the edges. Problems solved. Thermally conductive *and* it's adhered.
 
LaZeRz

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i ordered my drivers as STRICT 1.3a so they dont overpower my diode since i dont got much heatsinking but DTR runs diodes at up to 1900ma on some of his 2.1w builds :drool:

1.6-1.7amps should be fine aslong as you have a good heatsink and a moderate cycle :D
 
weidmark

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I think Jordan does a max of 1.8A as he says there are diminishing returns after that point.

1.6A is fine for the diode. As for duty cycle is depends on what host/HS you use. Some builds can handle 5minutes+ some should stay at a minute. Yes even at 1.8A :).

OUt of curiosity... what host are you using?

LaZeRz said:
i ordered my drivers as STRICT 1.3a so they dont overpower my diode since i dont got much heatsinking but DTR runs diodes at up to 1900ma on some of his 2.1w builds :drool:

1.6-1.7amps should be fine aslong as you have a good heatsink and a moderate cycle :D
Click to expand...
 
LaZeRz

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Yeh most of his builds are set too 1.8a (ive seen em all :D) but for the sake of power in some tests he runs them at 1.9a for a bit but then turns them back down :)
 
rhd

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Confused here -

Jib's drivers (at least the one you're using here) is based on an Lm1117. My sense is that this is a DDL type circuit - IE, the IC is used as a constant current source. Which means it has a resistor set to deliver 1.3A

So why would you get more, ever?

I understand that you *could* get more if you actively changed the resistor to provide for a higher value by means of the 1.25/X calculation. But obviously OP hasn't done that, otherwise he wouldn't have asked this question. So what IS going on here?
 
LaZeRz

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jib77 said:
These are set to the max the IC can do, in my test this is 1.3A without heatsinking and 1.5-1.6 with GOOD heatsinking. I do not have resistors to set them to anything else. Its like Southwest Airlines, its cheap because I use 1 set of parts for all of them (allows for volume discounts for the parts). I do have a 1.8A driver in the pipeline though, Im hoping to have those available sometime next week.
Click to expand...


it seems they output more with heatsinking :D

o yeh +1 for you Rhd
 
Wolfman29

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Well, I was wondering the same thing myself... because the resistors are two 1 Ohm resistors and they look like they are in parallel... two 1 Ohms would be .5 Ohms, which would yeild 2.5A, which is far too much. What's the circuit structure on these?
 
rhd

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Jib:
When you say you set them to the max the IC can do, I'm a little bit confused still. You're still relying on that 1.25 / X equation, aren't you? So isn't there a "set current", even if that's not exactly 1.3A?

EDIT: Wolfman beat me to essentially the same question. If the drivers are wired to *try* for 2.5A, then how are they constant current sources? Is it really ok to rely on the inherent current restrictions of the IC to accomplish current limiting? (maybe it IS, I don't know, that was a legitimate question)

EDIT (again): Question #2, why does the IC suggest that it's a 117, not a 1117 ?
Subtle difference, but the 117 isn't LDO and the 1117 is - I always assumed these were 1117 based drivers until I looked that the photos.
 
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DTR

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LaZeRz said:
Yeh most of his builds are set too 1.8a (ive seen em all :D) but for the sake of power in some tests he runs them at 1.9a for a bit but then turns them back down :)
Click to expand...

:thinking: I do?
 
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Wolfman29

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Turns out there is also a 3.2A spike on start-up... I am starting to think that this driver isn't as effective as I thought it was o.o
 
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