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New - "A better 1W budget boost driver" - AK-007

jayrob

jayrob

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rhd said:
Also - modes are bypassed if you just take the negative feed directly instead of from the driver.
Click to expand...

I read through the thread, but may have missed it in case it was already mentioned.

But if this driver is regulating through the negative side like many LED drivers do, then if you take the negative feed directly as you mention, then you will not only be by-passing the other modes, but this will by-pass the driver entirely, and run directly off of the supply.

That is if it is a driver that regulates through it's negative side...

Might want to check that and see if that is what is happening...
 





rhd

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Hey Jayrob,

It's actually NOT the case here. I think in a later post I mentioned that I had jumped the gun on saying that modes were bypassed.

However, most of these drivers (I think the NJG-18 is a typical/great example) regulate the positive side anyway. With the NJG-18, if you take the negative feed from the battery, instead of just from the driver, it does indeed bypass modes (the way I described it incorrectly initially here)

Having said that, again, it doesn't actually look like that was the case with this driver after all. But it is the way many drivers work. To my knowledge, almost all of these re-purposed LED drivers regulate the positive side anyway, don't they?
 
jayrob

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I've only used maybe 6 or 8 different LED drivers and most of them regulate through the negative side, but a couple of them regulated through the positive side...

So it's just a matter of testing to make sure is all.

That's why I mentioned it. Because I have seem them both ways. But mostly through the negative side...
 
rhd

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Interesting -

That's worth testing then. Though just for the purposes of our exploration of this driver, I'll point out that all of the data I initially reported was obtained through testing using the driver's +/- output leads, and the battery connected to the driver's +/- inputs.

Also, the - input and - output tested as continuous on my DMM
EDIT: I'm actually not 100% sure about ^ I think they did, but it's been a few weeks, and I don't have one in front of me.
 
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jayrob

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rhd said:
Interesting -

That's worth testing then. Though just for the purposes of our exploration of this driver, I'll point out that all of the data I initially reported was obtained through testing using the driver's +/- output leads, and the battery connected to the driver's +/- inputs.

Also, the - input and - output tested as continuous on my DMM
EDIT: I'm actually not 100% sure about ^ I think they did, but it's been a few weeks, and I don't have one in front of me.
Click to expand...

Hmmm... well then if the negative input and negative output are continuous, then the driver will be regulating through the positive side...
 
Mohrenberg

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I opened one and it has the "270" resistor on the bottom PCB.
I'd go to the basement to experiment but I've got to learn these cardiac drugs/doses as well as the American heart association's advanced cardiac life support algorithms before tuesday :(
I know i failed my static and dynamic ECG practicals last week because although i could interpret every cardiac rhythm they gave me, I didn't know the treatment modality or the drugs and dosages to use.
I don't just have to learn them, but memorize and be able to recite them.
 
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Morgan

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It should probably be pointed out that these drivers are going to be very happy to suck your LiPo batteries well below the safe discharge levels. The drivers may only be a few bucks but having to replace your batteries will quickly turn your purchase into a false economy, if not a risky business when it comes to recharging them.

M
:)
 
rhd

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100x over thumbs up on that observation ^

The same should be said for the NJG-18, and almost any other re-purposed LED boost driver. To boost a LED implies source voltages below the LED Vf, which itself is typically around (or below) save li-ion discharge level.

In other words, we're boosting from 3.7V up to ~5V, with drivers meant to boost 1.5V up to ~3V. The drivers will be quite happy to operate and their typical 1.5 ;)

Protected cells will offload the appropriate protection into the cell - might be worth using them exclusively with LED boost drivers.
 
rhd

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Ya, sorry guys. All of my lasering gear ;) is still in a FedEx box making its way across the country to meet me. Plus, there aren't any of those drivers in that box for me anyway, those are on their way from DX. A couple people in this thread have some (and I think BH bought some from Moh). It would be super quick for someone to put the continuity probes on their DMM onto the (-) input and output and see if they get a beep :)
 
123splat

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O.K. guys, I got my three AK's lastnight. I put the VOM on the negative leads and got over-range reading with the meter set on 200 Ohm scale, in both directions (red lead on output black wire, black lead on outter ring of regulator, and vice versa). Negative NOT common in driver circuit. Red VOM lead on Red driver output lead, black VOM on inner ring of driver, about 120 Ohms. Black VOM lead on driver RED output and RED VOM lead on inner ring of driver, over-range. Positive NOT common. Sounds pretty much like a Boost regulator,,,, (Just incase anybody wonders, Yes, the VOM Red is sense (+) and the Black is common (-).
Results same for all three drivers.
Now in exchange for that priceless bit of trivia, so, How DO you change modes on this (AK-007) driver?
 
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