You were right. Leda pin 1 goes to upper AOEC top left pin. What else to check b4 I leave?
Hi, I think I found more of the connections:
Here’s the link to the diodes I was looking at:
Leave for the night?
Anyway I can’t come up with much to check at the moment.
I’d check out the modes chip a little more. One pin should hook to a supply voltage - in this case that would be hooking to the side of W8 with a line on it I think. Another pin should hook to real GND I think. Another pin should hook to the QX9920. And another pin I think will connect to that brown capacitor next to W8.
Mostly that stuff might give us a lead on the identity of the modes chip, or whether it’s feasible to replace it with something like a SOT23-6 Atmel ATtiny10. Granted you might need to drum up a little more interest in this driver for anyone to want to work on that… IMO efficiency would need to get to 75-90% at 3A for this thing to get really interesting. Maybe try one of the SOT23-3 FETs the BLF15DD folks have been talking about, I dunno.
Thermal putty is something like this:
I guess that it’s more correctly “thermally conductive putty”, i.e., putty-like stuff that is able to conduct heat. Hank at IOS use to include a couple of small blocks with some of the drivers he sold (maybe still does).
I missed your post #133 above. I’ll check the FET from the BLF thread:
EDIT: FYI, as you probably guessed, I’m more interested in trying to do what you talked about in your last paragraph above, i.e., to try to increase the efficiency.
I think the reason that I actually like blinky modes is that when I’m testing drivers, it sometimes the only way to tell if the driver is actually in use, vs. a short and going to direct drive, because on the bench, it’s sometimes hard to tell low mode from high mode.
Maybe if I actually USED my lights, I’d hate the blinkies, but for testing drivers, they’re very helpful :)!
I assumed that AOEC was an Alpha and Omega Semiconductor FET since it started with AO. Now I realize that I was probably wrong about that. Who knows what those markings indicate, but I think it’s a fair guess that replacing the FET is a good move. May as well replace both of course.
My test LED is on a little (20mm diameter x 25mm tall or so) copper rod. I sit an LED light bulb diffusing dome over top of that. It’s generally fairly easy to tell the modes apart, but things do still look very bright on either high or a short… so I know what you mean.
Sorry, re. “leave”, I meant leave my basement, where I have my so-called workshop set up :).
I’ll try to check if the QX92920/LEDA 1322 pin connections are as you suspected above.
EDIT: And I have some of those AO FETs in my Digi-key cart.
OK, but the pins I discussed in the post you quoted are NOT for the QX9920. They are for the modes chip, the unmarked SOT23-6 package chip.
Ok, sorry - understood.
I know that I keep going off-topic on this thread, but despite wanting to fully paramerize this driver, I’m really “feeling the need” to put one of these in a small/tiny host :(. I was messing around with the one with the R100 stacked on the R200, with an MT-G2, and got to 6.2V @ 2.99 amps on the emitter (according to the el-cheapo laser-guided thermometer I had, the emitter got to 197F, and the driver to about 98F, so things would get a bit toasty :laughing:!
Wherever you put it, the driver will need to be heatsinked.
No thermal protection, no LVP, no turbo stepdown… sounds like a pipebomb ;-). And I’m not saying I wouldn’t do it. :-p Just take the usual precautions. 1/2 twist will fully lock out a Roche F12, so that’s maybe an option for 2x18350 & an MT-G2.
I’m actually thinking smaller than 2x18350 :)…
EDIT: I did say “tiny” :)…
Now that I think about it I doubt that 2*18350 would fit in that host anyway.
FYI, I haven’t abandoned or given up on this yet. I’m still waiting for the new FET and diode. In the meantime, I’ve been trying to get one of the drivers (the one with R200 and R100 stacked) into a small light, but the pill was too short to accommodate this driver with the toroid (the toroid was just a tiny bit too tall), so I’m back to waiting for the parts.
I’ve been thinking that when the parts come in, I may pull the toroid off, so I’ll take pictures if I do that.
It may be possible to use an SMD torroid on air-wires instead of that big one. OTOH we don’t know the inductance so we’d be guessing and might fry stuff.
Let’s see how the new FETs and diode do first. I wasn’t necessarily interested in putting the driver in that particular light… it was more to kill some time.
The diodes and FETs from Digikey came in earlier this week (they ship FAST), but I hadn’t had time to try them until now, and I only had time to try a quick swap of the diode so far on the board that has the R100 stacked on top of the original R200.
It was kind of a pain, as I don’t really have any SMD tools, so I just used my soldering iron to pull the original SS34 off, which left solder still on the pads, so I then put some flux on the pads (my original intention for that was mainly to prevent the new diode from blowing off the board when I used my heat gun). I then put the diode on the pads, and used my heat gun, on “low” blower setting, but with the highest temperature, and was pleased that it actually reflowed the new diode without blowing all of the other components off of the board.
Anyway, I re-soldered the toroid and the emitter leads, and did a quick test and the driver still worked (it still has the blinky modes, etc.). I only did some short tests, maybe 30 - 60 secs on high, measuring at the emitter with a clamp, I was able to get 4+ amps at the emitter, and no puffs of smoke or burning odor.
Note that I haven’t switched the FETs (the A0EC/AOEC?) out yet.
Now, I have to really find a light to put this into, as the pill on the one I tried earlier was much too shallow (height-wise).
P.S. Emitter was an old XM-L something that I had reflowed on to a Noctigon, and the Noctigon was sitting on a 2” x 2” x (maybe) 1/4” piece of copper from an old CPU heatsink.
EDIT: This is the diode I used for the above: http://www.digikey.com/short/vp9q2
EDIT 2: Here’s a pic I took of a test. The emitter wire is looped through the clamp meter, as wight (I think) suggested, so the current (8.89) is twice the actual emitter current (~4.45 amps). The current (4.5 amps) and voltage (4.7V) on the power supply display (in the background) should be about right:
LowLumen suggested looping the wire on your clamp meter to improve the results, not me.
Is your PSU set to 4.7v? That’s not telling you much since you’ll never hit that voltage with li-ions.
I could get to 4.7V (or more) with 2xLi-ion :)…
EDIT: Thanks for correcting the reference about looping the wire also…
Bump this thread. Apparently this is the driver used in the Uniquefire 1405. So is this the only 16.5mm buck driver we can find at the moment or is there any other choices?
- SF’s dropins have a small 2.2A buck driver (QX9920 based).
- DX sells this AX2002 based 1.25A driver which can be pushed to about 2A.
I think everything else on the market in 17mm is pretty low current (as if we didn’t already consider 2A low).