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Buck or boost?
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#1 (permalink)      7/23/2013 4:01:16 PM US Central   quote/reply + tips
kokopelli
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Buck or boost?
This driver has a coil on it so it must be more than a 1 mode linear driver. Does it work in a range like 1v-4.2v (boost driver) or something like 3v - 18v (buck driver)?
#2 (permalink)      7/27/2013 6:17:17 PM US Central   quote/reply + tips
dave_
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Well, from the diode/coil/output constallation you can tell it's a buck converter. (If the picture is the right one, of course. ;-))
The parameters in the description are at least consistent with that, so I guess its a ~4.2Vmax buck driver.
#3 (permalink)      7/27/2013 10:31:12 PM US Central   quote/reply + tips
kokopelli
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A 4.2v buck driver doesn't make much sense. I'd expect to see 8.4v or higher from a buck converter to be meaningful. AMC kind linear drivers work effective enough for 4.2v and lower, as cells usually keep at 3.8v under load and down to 3.4 v of an XML emitter you get 90% efficiency which a buck driver would struggle to reach.
#4 (permalink)      7/28/2013 7:43:17 AM US Central   quote/reply + tips
dave_
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Actually,a 4.2V buck driver would make quite a lot sense. This is a 800mA driver, so LED forward voltage of an XM-L will be 2.9V at room temperature and even falling while it gets warmer. A simple buck driver that can achieve ~85% eff. without to much trouble would offer a significant runtime advantage over a linear driver solution.
There are 4.8..~5.5V max buck LED driver ICs out there, independent from your expectations.
Sadly they sanded down the markings, so I guess the manufacturer is not willing to share which part he has used.
It might very well be that the part can operate at a higher voltages, but I have the feeling we will never get the actual specs. ^^
#5 (permalink)      7/28/2013 8:01:14 AM US Central   quote/reply + tips
kokopelli
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I found a couple of these in the stack of drivers I ordered last year. I guess I'd better check one and see if it can work below led voltage and if over 4.2v.

Thanks for the information BTW. I always have thought a flashlight driver should be made with a reason, like to boost or buck, since 1.5$ is just too little money for one to think of better efficiency in a driver instead of just use a current limiter.
#6 (permalink)      9/24/2013 11:42:40 AM US Central   quote/reply + tips
Werner
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Anyone tested this with 5-6V?
#7 (permalink)      9/29/2013 7:32:20 AM US Central   quote/reply + tips
maciex
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AX2002 Can someone confirm?
#8 (permalink)      11/29/2013 3:32:53 AM US Central   quote/reply + tips
beniwo
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From review: "First problem, the driver drops out of regulation very fast, at about 3.7V", so this could be AX2002, according to datasheet input voltage should be 3.6-23V. Seems to be not good product.

Edited on 11/29/2013 at 3:35 AM. Reason:
#9 (permalink)      12/12/2013 11:33:38 PM US Central   quote/reply + tips
alexvh
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I believe it is AX2002. Mine has part of the large A and X still visible.
#10 (permalink)      12/13/2013 3:55:46 PM US Central   quote/reply + tips
maciex
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AX2002 is a good driver but not for 1x18650.
#11 (permalink)      7/30/2014 2:51:10 AM US Central   quote/reply + tips
Volosaty
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AX2002 lives in SOP-8. On this driver we can see a SOT-23-6, so it's definitely not AX2002