[WIP] 17mm DD+single-7135 driver / single sided / Dual-PWM

wight - was there a v013 in the 17 mm version? Latest I thought was v009, as in this OP. Could not find a 013 on OSHPark under your name, but Dale posted a v013 version. Any other changes of note between x009 and v014?

That’s a fair question Tom E. The answer is I don’t think so. I can’t be positive of course.

v009 - last public release
v010 through v013 - all marked “group-buy_with-star”
v014 - schematic cleanup

v014 should be identical to v013. The Chinese fabs tweaked v013 a fair amount so most folks probably haven’t seen a ‘real’ v013 I think. Sending over the gerbers for v013 was probably my last involvement with the BLF A6 group-buy and I haven’t reviewed exactly what was changed for cheap-fab production. Obviously the star is different. I think silk was also changed.

v014 vs v009: Looks like the exposed copper was expanded a lot on the edges , the star was added, bottom silk now reflects the “A17DD-L” nomenclature vs the earlier name, the spring pad was changed significantly (hopefully to support common spring sizes? or maybe just look snazzy? who knows :-(), and consequently lots of silk locations were tweaked slightly on the top and bottom.

Do you have a link to Dale’s pic? I always enjoy looking at the built pics. I don’t think I have any v013 or v014’s here. I’m certain that I have not built one.


EDIT: I think that v14 is intended to be easy for 5mm or 11mm springs.

  • The OD of the inner spring pad is 6mm, which should be decent for 5mm springs/buttons or workable for 6mm brass buttons (doesn’t someone sell 6’s?) I wonder why I didn’t add some 0.5mm centering indents to help 5mm items stay put? Probably just because Eagle makes it a pain.
  • The ID of the four outer spring pads is 5.5mm. That’s probably a (big) stretch for 10mm springs but I think that it should be a good/decent fit for the 11mm OD springs. Clearly this isn’t suitable for mass production with the star there, but for hand assembly I think that the 4 point setup should provide an easy-to-build and attractive setup. I stand ready to be proven wrong of course.
  • To me this thing doesn’t seem very friendly for 8mm OD springs at all. There’s plenty of copper to scrape in a pinch. I’ll continue to think about how to make it attractive looking and have 8mm guides. I’m a slave to form…

For those who aren’t clear on why the OD of the pads are actually larger than the OD of the spring - it can be very difficult to get the soldering iron to heat the pad and spring nicely when there isn’t a bit of extra space on the pad.

Ohhh - think Dale's post on v013 was in the humongous BLF Kronos X6/X5 thread, long buried by 100's of posts by now, only hours later Undecided.

Thanks wight for the info! I do like the expansion outer tabs for the springs - definitely useful.

In the last couple days I used one of you 009's with a ATTiny85, pins bent in, and piggybacked to the stock driver. The stock driver had a blue LED on it that shines thru the rubber around an e-switch. So, I left the LED and resistor (also switch and charger connector) on the stock driver/contact board, and wired MCU pin #3 to the resistor of the LED. So far it's working great! Got some more tweaks to make to the Narsil firmware to fix bugs, and have it handle low battery alerts, but it's working real nice. Even with the wire on pin #3, I can still clip the MCU for programming because the bent pins elevate the MCU up. Would much rather have a pad for pin #3 on the component side for doing this, but you probably don't have space.

For me, using pin #3 as a jumper doesn't help - I got lots of configuration options in the UI of Narsil.

  • Ah, thanks. I was able to find it based on that. The post you were referring to is #4869 and shows a “real” v13 from OSH Park. The discussion going on around/before that post seems to cover a lot of ground we’ve already covered. I think Sharpie had the Gerber viewer set with a layer missing. :wink: Some points are still valid, even if they’ve been touched on before.
  • I agree with you - the star doesn’t do much for me except look cool. I don’t use stars.
  • Maybe later I’ll scoot things around on a 20mm board and break out the extra pins. I prefer to break them out when I can, but as you’ve mentioned space is at a premium.
  • Please be sure to report back on your results with those spring pads.

I’ll post my question and the answer from wight here if someone is interested :

… and I don’t use stars any more either. It seems to have become an obsolete carry-over from nanjg days. But I sure could use a convenient pad to solder other stuff to, like an e-switch.

The tiny25/85 efforts have really expanded options, and reduced the need to actually open up the light to make changes.

Another option is to choose a FET with higher on resistance. You will reduce peak current, get rid of turbo-to-moon blink, and save several dimes.

This might not be a great idea. I plead the fifth.

  • This is a Zener+resistor setup placed behind a polarity protection diode. Normally the polarity protection diode might cause our infamous boost problem, but with a 5v zener in place this should not occur. I expect that this should allow for a much smaller decoupling cap for the MCU… but I’ve been wrong before. At this moment I’m not actually certain whether this setup presents a quiescent current problem for single-cell momentary lights.
  • 17mm layout… which is a mess of course.
  • 0603 and SOD-323 sized passives.
  • 2mm via for positive.
  • This passes DRC.
  • Physical component keepout is 0.8mm rather than 1.0mm. Electrical keepout remains at 0.5mm.
  • LED- is smaller than I’d like.
  • GND vias are all placeholders.

BTW, any ideas on how to enable a bleeder to leak power to a lighted tailcap while off, without interfering with OTC drain? Or how to influence the rate of OTC drain?

Also, any thoughts on how to reduce power fluctuations at the MCU when the main FET power circuit is repeatedly going from zero to a zillion amps? It seems to have sort of a splash effect, and the tiny25/45/85 chips aren’t as splash-resistant as the tiny13.

RE: point #2 - that’s what post #300 is really about. Tom E has combated that effect by adding a ton of capacitance (20uH total), but I feel like that’s a bandaid type solution. I’m very interested in comments on what I’ve drawn up and shown in post #300.

RE: point #1 - crap, I felt like I was forgetting something as I worked on this board. Adding a that tailcap-led-setup was on the to-do list. I just looked it up… apparently pilotdog68 has just been putting a 560 ohm resistor across BAT+/BAT- on the driver.

EDIT: also, my thoughts on influencing the rate of OTC drain are still what they were a few days ago in the A17DD-SO8 thread. What I said over there was that it might be better to increase the capacity of the OTC by an order of magnitude or so and then use a bleeder resistor of our choosing. Clearly this PCB is going to get crowded with all that stuff (especially because a good 10uF cap for the application will be 0805 or larger). I also haven’t thought this idea all the way through at all, it may not really make sense once I put it on paper. I suspect that I’d better think some more and look at the datasheet. In the meantime if someone wants to play around with it they are welcome to do so. It would be a straightforward thing to experiment with.

Ohh btw, I pulled the C1 cap off of a SS/Cu X5 (based on this FET+1 design) using a ATTin25, and tested it - best I can tell it's a 12 uF cap. On my DMM, 10 uF caps tests at ~9.6 uF, 22 uF caps also tested a little lower, so the cap off the SS/Cu X5 board tested at 11.5 uF.

Sorry, but I'm not sure I understand enuf to comment on your proposal. But also I would like to make it clear I don't care about 13A's any longer - only interested in 25's and 85's. I consider 13A's obsolete now - all I've been working on over the last few months is 85's (e-switch based) and 25's clicky based. I don't mind the 13A footprint because the bent pin setup for the 85 works well, but I do want an 85 to work reliably in a high powered setup, preferably with the SIR800DP FET. Raising the value of the cap seems to fix the problems - I've had these problems on pretty much every 25 and 85 board I've built (maybe 15-20), seems like. It may be a bandaid, true, but it's the only bandaid that works reliably. I didn't do this on my own - it was recommended by EE's, both here on BLF and at work here. I was just the one trying it, testing it.

Edit: wait... from what I recall, it was recommended the cap be as close to the MCU Vcc pin as possible, and this is what you did here. Also a big cap after the diode could be trouble, but the smaller cap you are using is a good thing for sure. Hhmmm. This may address issues the EE's raised - you might be good goin in this direction, but I dunno much bout these things, but dang - looks pretty good!

One of my other "fixes" that worked was adding a 0.1 uF cap across the MCU pins of grnd to Vcc. I literally have the cap sitting on top of the MCU wired that way, and actually can still clip the MCU and re-program it. This was my typcial "fix" for my e-switch Narsil based 85 FET+1 v009 drivers, and seemed to work, accept for the last one over the weekend -- had to double up the 10 uF cap to get it working.

Thanks for the [unquoted] info Tom E. As for the quoted bit… I’m pretty sure that it’s the wrong analysis. The issue w/ a cap after the diode in previous FET/DD setups was that there was enough inductance in the circuit to get an unwanted boost circuit with the diode followed by a cap. I think that a smaller cap would actually tend to make this worse if everything else was left the same. In this case everything else is not left the same, I’ve added the Zener/resistor combo to hopefully get rid of the extra voltage from the [unwanted] boost circuit. The boost circuit is certainly still there, the extra volts are just getting dumped by the Zener. At least that’s the plan.

Using big caps to get rid of unwanted voltage spikes isn’t inherently bad AFAIK, but in our case it’s not something that we necessarily have a lot of space for. Replacing 1 extra 0805 cap with 2 extra 0603/SOD-123 sized components isn’t necessarily the greatest achievement in the world (heh), it’s just something to chew on. Without putting an oscilloscope on the circuit and checking things, I suspect that if this circuit works as intended it may also clamp the voltage better and tolerate bigger spikes. And of course it adds pads for a Zener.

Yep, I'm clueless with this stuff - I kind of/sort of understand you -- just forget bout my attempt analysis .

In one of my lights with this driver the voltage indicator only works when the light is hot. Probably a bad solder connection. Since I can’t find a circuit diagram - could someone point me to the most suspect components?
Thanks
Michael

Meh, I still listen anyway. :wink:

I’d say to check R1/R2 and all the pins Pin 7 on the MCU.

Thanks!
Finally I resoldered all pins of all components. Everything ok now, got even 2 more amps. 14 amps in total now with my triple Convoy S2+. Of course I could use this light as a soldering iron after 30 seconds …
Great driver!

That’s great. 14 amps is impressive. What emitters are you using?

3x XP-L HI U6. With full LG HE4 battery. I use this battery in this light only for tests, it gets too hot. Protected Keeppower 2900 for daily use give a max of 9 amps, 18350 efest purple even 10 amps. Still plenty …

BTW, I’ve heard a few times not to use a zener on an e-switch light since it drains power in standby mode. Would the same apply to a clicky with lighted tail, or is it pretty much irrelevant since the standby power should mostly be going through a bleeder instead of the rest of the circuit?

I’d think you’ll have a different problem: How will you reconcile the voltage of the series cells to the Vf of the tailcap lights? Are you using 6v tailcap LEDs or putting two (or more) in series to get the forward voltage up?