Driver specs (DX 15880, KD 5313/5314)

http://www.dealextreme.com/details.dx/sku.15880
http://kaidomain.com/ProductDetails.aspx?ProductId=5313 (5314 is the same but in a 5-pack)

Are these fully regulated? I've searched a bit, but haven't found a conclusive answer.
DX doesn't list specifications, and the only thing that KD says is (after de-engrification):

Battery>3.7V>LED VF = Buck regulated
Battery<3.7V<LED VF = Boost regulated

But how does it behave if, say, the battery has more than 3.7V but the Vf is higher? Or if the battery has less than 3.7V but vF is lower?

Say the battery is 4.2V but the led Vf is 3.8 (Battery > 3.7V < LED VF); would this mean it'd direct-drive (and thus probably fry) the emitter?

Some part of my brain is suggesting me that I'm not seeing something elementary and this might be an incredibly stupid question, but I can't quite put my finger on it, so I'll ask anyway and take the risk of looking like an idiot.

What I'm looking for is a buck-boost that will provide regulation at all times, except obviously when the battery is so low that it can't give the necessary current anymore. Does this do that?

Thanks.

bump

??

Have a look at the results in this post (in russian unfortunately).

http://speleo.ru/phpBB3/viewtopic.php?p=2479#p2479

When run off an odd combination of batteries (3AAA + 1AA) it provided regulated output and didn't fry the emitter.

That seems to indicate that it doesn't go direct drive, it is either regulated boost or regulated buck. I've got one and playing with it (3x1.5V AA) it didn't cook my emitter either.

In the end I ordered a five-pack. I'll get it in a month or so (standard shipping time from KD to here), and then I'll report on my findings.

From the maker's original sale post, he said the driver is two stage.

Front stage is an adjustable constant voltage boost regulator.
Second stage is an adjustable linear constant current regulator.

The driver is okay up to 4.5v input. The mos will heat up quickly if the input voltage is higher than that.

I think the resistors on the spring side is the sense resistors but I don't know the equation. I didn't have this driver in hand, thus I don't know which IC he used.

What exactly does "adjustable" mean? Could one use trimpots to set exactly how much current goes to the LED?

DX SKU 7882 has a POT and that be used to vary the output, it seems to perform a similar function to 15880, except has more modes, is adjustable and is also cheaper although the leads were more difficult to solder on (I've had two, one with leads, one without).

Can't see pots on 15880. Perhaps one can be added in place of a resistor?

Fallingwater said:

What exactly does "adjustable" mean? Could one use trimpots to set exactly how much current goes to the LED?

Click to expand...

No, there's no trimpots. I think he means it could be changed to "fixed" to another voltage/current. (change the sense resistors?)

It seems like there should be a data sheet for this board or the led driver IC some where. I have turned up this interesting thread https://www.candlepowerforums.com/threads/218235I
but no data sheet.
I would sure like to find that because I need to lower the current delivered to 700ma for a single red-orange led that's only rated to 700ma. In the thread mentioned people able to actually remove the IC that controls the modes, surely some one knows which of the 6 resistors can be changed to reduce the max current form 1.0A to 700ma.

Anyone have any luck changing mode groups on the KD flavor? In low I get the brief flicker after a second or two. Have been trying for at least 10 minutes here to enter another group but no luck. Hoping for group A low/mid/high.

I run the KD one .... It is not Direct drive on high with a 4.2v Li-ion ...

How well regulated ? , it boosts with 1xAA and 2xAA , and with a 18650/CR123A it draws right around 1.2A and no higher ... Which suggests to me that it is maintaining 1A to the LED [ hopefully ] ..

KD sells another one , which seems to go DD , but it has low voltage warning @ 3v and just blinks in warning mode with 2xAA , but it does seem to work with a single AA , but does not boost any harder than the driver talked about here .

I use the KD driver in my 2xAA set ups ...

Aaaah , yes , ... In low , wait for the flash , then 5 clicks [ half clicks like when you change modes ] and it should take you to the next series of modes .

old4570 said:

Aaaah , yes , ... In low , wait for the flash , then 5 clicks [ half clicks like when you change modes ] and it should take you to the next series of modes .

Click to expand...

Thanks for that but I still don't seem to be having any luck. I notice there is a quick flash in both medium, and high both. It just seems to indicate the mode has been memorized. I will keep plugging away at it. Any suggestions?

well you cannot get something that ain't! Really...

Since I published my readings I have recieved the same driver from KD twice more and all drivers were 5 mode with a similar behavior like yours....Go figure

Since then i have left this driver option behind.....