Evaluation of new round nFlex driver from TaskLED !!!

wquiles

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I have been fortunate enough to receive for evaluation one of the prototypes that George (CPF handle "georges80") resently designed. I will get into more details below, but this new converter ROCKS !!!

I have used the Fatman, the original nFlex, and the D2DIM, so I am not "new" to converters from George. This new converter, like the nFlex, is a buck CC (Constant Current) converter, meaning it needs a higher voltage than the vf (or sums of vf's) plus some operating margin, to stay in regulation. Two things set this version apart - the size, and the new menu/features.

To test the driver I used my trusty LightBox, which was designed to allow for quick driver changes, as shown here:
IMG_6855.JPG



In this setup I use a large, solid CPU heatsink with a fan to keep the LED cool, regardless of drive level or duration. For this test I selected a VY0T Luxeon 5W LED as the guinnea pig:
IMG_6856.JPG



George sent wiring instructions, which I printed "a little" bit oversize to review on my bench:
IMG_6858.JPG



Here on the left is the new round nFlex (about 1.0" dia) next to the D2DIM (0.84" dia):
IMG_6861.JPG



Here I got everything ready for the test:
IMG_6862.JPG


IMG_6863.JPG



When George said that his nFlex is sent set to 350mA drive level, George is not kidding!!!:
IMG_6864.JPG



Here is the LED in "action":
IMG_6873.JPG



These are hard to read, but note how the converter uses more current at 8.4V (0.94A) input than at 12V (0.65A), like a CC driver should:
IMG_6870.JPG


IMG_6869.JPG



I was able to navigate through the menu and played with most options. I changed the drive level from 350mA to 1000mA and also changed the low-voltage battery warning point (new feature) to 08.4 and later to 07.0 volts. I tested both with my calibrated HP bench supply and this feature and the built-in hysteresis (also a new feature - prevents oscillation when the battery is depleted) included in this software/firmware works fantastic !!!

I also tested for fit/size and it does comfortably fits inside a "C" Mag (last photo looks like a cool "bug"):
IMG_6874.JPG


IMG_6875.JPG


IMG_6876.JPG



I think George has a hell of a winner here which should sell better than the regular nFlex since now it is usable in both D and C Mag hosts.

Thanks much to George for the opportunity to play with the round nFlex ;)

Will
 
Last edited:

Icarus

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This is fantastic news! :party:
Once again you did a great job George! :twothumbs
Thanks for sharing Will. :thumbsup:
 

jtice

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Thanks for the input Will.
Looks like yet another winner from George !!!
ah and I see Iracus has already spotted it,
I see some sweeeeeet C mags coming in the future. :p

~John
 

Anglepoise

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Thanks for the great post. When George does it......he does it right.

Having an adjustable low voltage warning is fantastic news for us re chargeable guys.

And being able to easily set and re set the max ma without having to solder those tine sense resistors. Priceless.
 

cmacclel

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Is the new nFlex driver still limited to 1000ma maximum current or has it been upgraded to 1400ma as the MaxFlex?

Mac
 

wquiles

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Good question. I know that at least for this prototype that I evaluated the drive current "tables"/options still listed 1000mA as the maximum. I will let George reply/add more information as to possible future changes.

Will
 

georges80

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wquiles said:
Good question. I know that at least for this prototype that I evaluated the drive current "tables"/options still listed 1000mA as the maximum. I will let George reply/add more information as to possible future changes.

Will

1000mA is the max. Other than the cosmetic changes and new firmware and new uController, the round nFlex is the same 'engine' as the rectangular one.

I have a few other drivers on my plate right now, but when the 'dust' settles I'll look into what would be involved to produce a higher powered version. It would of course be based on a different switcher.

So many projects, so little time....

Oh, and THANKS for the review. And thanks to you folk for the interest in the new round nFlex. rFlex or nrFlex??

I'm hoping to have the round version (production PCB) available in < 2 weeks. The production version has a few layout tweaks versus the pictures of the prototype above, and also has a solder pad/hole for an external switch (parallels the onboard switch, just like nFlex).

cheers,
george.
 
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