17mm & 20/26/27mm single-sided DD/FET driver release: A17DD-SO8 / A20DD-SO8 / etc

Correct, C1 is not a great fit there. You may also place C1 right next to R2. There is plenty of space to put C1 Against the right-hand end of the Zener and either solder the other end to the GND ring (scrape first) or solder it to the GND side of R2. I’ve just checked to make sure it would work, I was able to solder the cap in there without an issue with the Zener already in place. Adding some extra solder will help. EDIT: be sure not to solder to the other end of R2 (the end pointed towards the middle of the PCB).

All of my first Zener mods had the Zener laying down, embracing the capacitor on a Qlite driver. Can’t see how this one would be any different.

Let me ask this then, if I already have the driver built (I’ve got 9 sitting waiting to be used) and I have need for a Zener modded version…can I add a second capacitor with the Zener? Do I need to remove the C1 from it’s original location?

I think it’s different. When I set a cap on those pads it looks a bit tricky to solder in place. The cap can’t touch both pads at once - the SOD123 pads are too far apart. Your Qlite builds had a 0805 cap sitting on a 0805 pad which is longer than the cap itself. The SOD123 Zener will actually just barely fit on long 0805 pads by itself…

Good question! The answer should be no problem. Add the cap, leave C1 in place, and you should be fine IMO. I’d bench test to be sure though.

Off to test my bench…

I wasn’t going to do it tonight, but my curiosity made me look at it, and from there I was a goner.

Piece of cake. Took a built A17DD-S08, removed the diode, stuck a 200 ohm resistor in it’s place, held the small capacitor between the pads with needle pointed tweezers and touched solder to the pad then the cap, same on the other side… cap in place. Located the Zener for position, laid it on it’s side cupping the cap, badda bing badda boom done!

Soldered on 2 20ga leads, stuck those to a 20mm Noctigon with an MT-G2 on it, soldered by ground lead from my test cell that has a switch soldered to the negative, taped a second cell to it. Fired it up! 5 modes, presto! :bigsmile:

Thanks Guys! Really appreciate it, that was kinda driving me nuts! My last 2 Zener mods I went back to the very first BLF FET boards from matt, out of retaliation. lol

lol, the ones with no GND ring? :evil:

Looks good. Thanks for posting the pic showing how it’s done!

I think making that joint is probably fine for those with enough soldering experience (and a pair of tweezers ;)), but some might find it difficult. The alternative placement I mentioned above also works best with a pair of tweezers, so I don’t know if it’s any easier.

I’ve only been soldering since I got the Hakko 888 station. I used to butcher stuff horribly with a 25 watt Weller iron or an old Sears dual power gun. I sucked, in very ugly ways with cold joints that broke.

So I’ve only really been successful for about 6 or 8 months. Might be close to a year now, don’t remember for sure. I DO remember that switching to the .031 solder helped tremendously even before the Hakko, then getting the right tool made all the difference in the world.

I’ve used a small variety of soldering tools. For years I used a 100W gun for everything (do not do that). I’ve had a 25W and a 40W iron IIRC. I also have an 80W iron for use on big, stubborn things. Eventually I got OK with the 40W I think. Then I got a knock-off temp controlled station. That was an improvement, but after 6 months or so it started having problems and within a year of purchasing the knockoff station I got a Hakko FX-888. I’ve been very pleased with the FX-888.

v043

https://oshpark.com/shared_projects/SQs9Pu4O

  • Updated top silk w/ L+/- identifiers & orientation mark for MCU.
  • Updated MOSFET footprint including tstop and tcream. Tcream isn’t perfect but it’s better than the old version (which put down way too much).
  • Updated spring bad on bottom. Main circle is exactly 8mm, the spurs extend to 11mm (for soldering on a 10mm spring). I’m still open to suggestions about what spring sizes people use.
  • Moved the lone via closer to center of board. Via is now w/in 0.5mm of being centered.
  • Updated bottom silk to fit new spring pad.

The via being 0.5mm away from centered is bothering me. I’m aware that I can improve the appearance of the bottom by rotating the spring pad & silkscreen a little more. That will likely happen in a future version.

Seems like moving the OTC to below the Zener should allow that via to be centered. The OTC trace would have to run between pins 7/8 edit 6/7 and the OTC pads would have to straddle the pwm trace but neither of those are untried.

That looks good!

Jumping in…

Edit: Before I do….if you’re gonna make any changes, is it possible to open up that center via enough to put a 22ga wire in it? Plug a wire in for the spring bypass and deliver current straight through the board to the needy side :wink:

Edit II: LOVE those solder pads for the spring!

Wight, you've really outdone yourself here with this driver--it is really that great. Those spring solder points are pretty cool. I know now how much time it takes to design and tweak these things, and even though I know you're faster than I am, I'm guessing at this point it is a 40+ hour design. Bravo!

Thanks wight for all the hard work, i went ahead and ordered few newer design will post pics when i get them.

I just ordered some of these 043 boards and stencils to go with them. Wanted you to know the stencil layout looked perfect! Looking forward to getting this one in, like the PZL it should look really nice installed in a light. :slight_smile:

Thanks everyone!

Fortunately for my sanity Eagle doesn’t seem to have an hours counter on my files. You’re right, I have a significant time investment into that layout. There’s approximately one component too many involved: I was easily able to create nice symmetrical layouts when I accidentally left a component out. :wink:

You’re right of course. This entire design was done with two considerations in mind:

  1. diagonally opposed LED+/- at the board edge
  2. some semblance of symmetry

So I can’t get away with moving the OTC there. This final iteration (there were many in between v030 and v041 - I only iterate version numbers when I save, and I only saved during that process when there was an idea I wanted to preserve) started with a component in that position and a hard battle was fought before R1 and R2 lined up at 90 degrees vs the rest to allow everything to fit. More hard battles were fought after that of course since everything failed the DRC if I recall correctly. :wink:

If enough space can be freed up to get the via centered and larger that can probably be done. In the meantime there’s no reason not to drill it out: just be sure to solder the top (component side) when you feed the 22AWG wire through the drilled hole.

Great! I do really appreciate pics of people’s builds, from the driver to the rest of the light.

… and BTW here is an unattractive (to me) v044 - OSH Park ~

As you can see, the central via has been moved again in order to center it on one axis in relation to the silk and exposed copper. The entire central medallion area is still skewed with relation to the B+/LED+ vias. IIRC those guide rings are for 11mm, 8mm, and 5mm… or something.

I plan to take that back to the drawing board and:

  • continue to think about how the central via can be handled
  • fix the skew on the bottom
  • re-do the spring pad like v043, but with a thin, solid combo guide ring for 6mm /5mm in the middle of the 8mm pad.

Today I had time at home with the family away, and was in a bold mood, so I went on building a A17DD-S08 driver, for use in a triple XP-L X6 build. I know Dale has built tons of them but being an electronically challenged person it was quite a task for me (and I failed in the end). Here's the inside story of a clumbsy and chaotic electronics noob, making all kinds of random assumptions leading to wrong decisions:

I had ordered a couple of v024 boards earlier, so then I had to get the parts, which was not easy without spending tons of shipping costs. I got an assortment of resistors and caps from ebay, in the meantime finding out that there is several sizes, and for the first time understanding what the heck '805' meant that pops up in several threads on BLF.

Cereal_Killer had sent me some parts for building a few drivers a few months ago, the nicest was that he sent me some Attiny MCU's on which he programmed my favorite custom UI with off-time mode-switching. From his parts I also used the diode (I know now what SOD23 means), and the 4K7 resistor, the 22K resistor I found in the ebay-assortment. In the meantime I have learned (I had to..) the smd resistor code, and that there is at least two widespread versions of them. Also I looked up again how the polarity of the diode can be found out (the stripe is facing the minus). Unfortunately C_K forgot to add the 4.7 uF cap, and my cap assortment only went up to 1 uF (I used one as off-time cap), so I had to scavenge the C1 from an old NANJG-driver, I picked it up from a 101-AK ().

I am allowing myself one Mouser order every year, and I wanted some XHP70's for trsting and some Rebels anyway so this was the time, and a good opportunity to order some of those PSMN3R030YLD FETS too, and Zener diodes (it took me half an hour to find a thread on BLF that did not just talk about zener diodes, but also contained a part code for it, thanks Ouchyfoot for asking that same question before) and 200 Ohm resistors (could not remember what those were for).

So now I was sorted, I'm a reflow pro, so the actual placing of the parts and reflow on my heatblock went fast and smooth. The morale here is: information is everything, it took me months of figuring how, and arranging parts, the actual build was 30 minutes.

I soldered an old XM-L2 on a board to the driver and pressed the battery against the driver. It fired up alright, but the mode-switching was all funky as well, something was not right (had to do a random number of half-presses to get to high and when on high, after two seconds I got 3 flashes followed by a output step-down, this all was not what C_K had programmed for me). Then I put the driver back on the heat block and swapped the custom-Attiny with a qlite Attiny. Still weird mode-behaviour. Then I swapped again to the 101-AK Attiny. Still modes were acting weird. I thought that it might have been my scavenged C1 cap since it did not come from the 105C but from the 101-AK, so swapped that to one from a disposed 105C. Still funky mode changing. Then I realised that the off-time cap was still there, so I removed it. Now I got a familiar working driver at least.

I decided to make another of these drivers because perhaps the custom-Attiny was not at fault, but the wrong C1 cap. So I re-used the custom-Attiny and made me another A17DD-S08, with the correct C1-cap. And mode-switching worked smooth on this one. I thought victory!

Encouraged by succes I went on to zener-mod the first driver (with the 101-AK-Attiny) in the workaround way that was tested out for v024 . Lucky for me Dale posted a picture of his build a bit north of this post, because else I would have had put in the zener backwards. I got it soldered in nicely with the cap cosy against the zener (I can solder well) and fired the driver up, nothing. Then I realised that also the diode had to be replaced by a resistor. Hoping that I had not destroyed the driver I replaced it with a 220K resistor (Dale's picture showed 2000 on the resistor, and with my newly acquired knowledge that had to be 200K-Ohm ). Still nothing. Then I decided that I was no good in this and rebuilt the driver to single-li-ion without zener-mod. When the zener was removed, C1-cap in original position, and RVP-diode back in, the driver was dead!!

Still happy with the second driver, I started playing with it, and now it appeared that mode-changing was indeed very smooth, but that in high mode the flashes plus step-down after just 2 seconds was still present in high mode, horrible! I did not test it long enough before on high to notice (test-ledboard was not attached to anything). What I am beginning to think now is that C_K has made some errors in his UI-programming. And also just now I read back in Ouchyfoots thread that the resistor to replace the LVP-diode in the zener-mod should have been 200 Ohm, not 220K (ah, that is why I orderded those :-( ), so it could have worked after all.

The morale of this story is that if you do not have much clue about real electronics and just go ahead with making these drivers, it really is hard, especially if you are a bit chaotic like me! The information is scattered all over the place because folks who really know their stuff (understandably) do not repeat the simple established things all over again (it took me back to a thread from 2010 to finally find out which pin on the ATTiny is pin5, it will be somewhere else as well, but I could not find it).

Sooo, after a whole day and two faulty drivers I'm a little wiser, so the next go at making these drivers will be easier. I may recover one of the drivers with a qlite-Attiny (with no mode-switching unfortunately), but because I will never be able to flash firmware to Attiny's (no windows computer, no skills, afraid of programming software) I am looking for a new source of programmed Attiny's that do allow off-time mode-switching.

BTW, I did make a video of the second reflow, and because I still think that reflowing looks like magic, here it is :-) :