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

The Zener is really actually pretty easy. There’s a “limiting” or “load” resistor, that’s the 100 ohm or 200 ohm or whatever resistor that’s placed on D1’s normal location. So one end of that resistor is wired directly to the MCU’s Vcc. The Zener is also wired directly to the MCU’s Vcc as well as GND. The cathode (striped end) goes towards Vcc, the other end goes to GND.

The Zener will self destruct without a current limiting resistor. It behaves sort of like a low-resistance short to GND. That’s why we add the resistor between Vin (BAT+) and the Zener, it prevents things from getting out of control and allows the Zener to pull Vcc down to the desired voltage.

I’d either put mine diagonally across D1 and R2 (from Vcc to GND) or horizontally from D1 across to FET pins 1-3 (GND).

Post a picture with the Zener laying in place and I’ll verify whether it’s correct.

EDIT: please try and fix the strike-through in your quote of the OP. For whatever reason it’s not working and I’d rather not have anyone get confused. Stacking on C1 is not acceptable for this driver.

Which FET Pins are 1-3? the outboard pins? or from the inner pad of D1 to the outer pad of R2?

Look at the PCB. Zoom in on OSH Park images if you need to.

I couldn’t get a good picture of the real thing, so this will have to suffice.

Looks fine.

Wight, any chance you could stretch this out to 20mm?

Yes, I will stretch this soon.

noob question: If I have no modes, only on/off, what did I do wrong? I’m assuming I have a short somewhere, but what is the most common place to look?

LED- to ground. Reflector is the most common, but I would also look at the connection point on the back of the FET.

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You can also double check that the black lead contact is clear on the star. I’ve seen that either touch the copper star or the side of the pill and give that result.

Check like Richard said that the lead on the mosfet isn’t touching the pill when it’s installed. The black lead from the driver, grounded out, bypasses the driver and goes direct drive.

Just ordered some of these to play! Thanks for putting this out there.

If the solder on the mcpcb sticks up you can carve it off with a knife or cover it with kapton tape(RMM sells thus stuff too).

Hmm, can i use that led - straight to the ground to get a stronger connection to my advantage if i want to do a DD build? So i connect the led - directly to bare aluminum in the pill/shelf instead of first down through the wire through the bare driver board like usual. Or would i get an even lower resistance circuit if i connect the led - to the copper DTP? If i use an conductive heatpaste like arctic silver.

Even better is if you solder the copper star to the brass pill and remove the dielectric layer under led- on the star. No modes, no low voltage protection, no brakes, really bright.

Yeah :slight_smile: now we are really cooking :bigsmile: & the low volt protection is me finding the XP-L V6 to boring to use after it goes under 3.8v because then it starts to dim to much :smiley:

Ok this light i am the process of modding today, the Zeusray doesn’t have a brass or copper pill & i don’t think it is possible to solder the star to the aluminum pill, at least i am not sure i could do it.
But i will do that if i want to do something
similar with a light that has soldereable pill.

But removing the dielectric layer i may be able to do, i have these on sinkpads 2 (i know this is a sinkpad 1 picture but i couldn’t find any of the second one in google)
So i think i would need to heat up the star to 185 degrees Celsius, remove the led, cool down the star & peel off the - side of the star & reflow the led back. Is it only the thin straight line i should remove or is it something i should do with the middle thicker copper square also?

Wouldn’t the led sit uneven if there is less height on the - side? or should i build up that side with a little extra solder paste?

You do realize, don’t you, that you CAN take it far enough that you fry emitters. Especially todays new breed of XM-L2 and XP-G2 (I think, check with RMM on the smaller one). They burn up much quicker than we’re used to, unable to do 6A much less 7A+.

Yes no worries i guess i could fry some :slight_smile:
But i haven’t seen any reports of burned copper DTP mounted led’s, thats reasonable well heatsinked, and actually not even bad heatsinked like SS or titanium anywhere. You have had 6,89A in a XP-L (V6?) yourself and that is working fine.

What seems to be happening from reports here & elsewhere, is that when they gets too hot on the copper DTP they desolder themself or the wires.

The only burned emitter i often hear about is boost or buck driven ones.

If i would suddenly start to burn out my lights, then i would know where the limits are, i wasn’t kidding or exaggerating when i said before that i need to take thing to there limit, to know what that is :wink: and then step back to safer levels (to not burn the led that is) because burnt skin heal :bigsmile: and led’s don’t :wink:
EDIT i will just add that by “burnt skin” refers to very hot builds not exploding builds :wink:

Thats what makes this interesting & fun for me & makes me do it, i really like to optimize things. And flashlights in various form factors is really fun to optimize.

I have seen you push the limits here Dale, aren’t you curious how far it is possible to take a build when running it DD with no brakes at all?

I recently realized that when i want little light i use my small edc light & when i want more light i use an larger light, but almost always if i am outside in the dark i only use max or turbo.

I do it all the time, lol.

Have you seen 16A to an MT-G2? Or 12A to an XHP70? But let me tell you, right at or just over 7A the XM-L2 POOF’s, every time. :stuck_out_tongue: (or at least 8 times in a row, YMMV)

What I have found, and what djozz has documented, is that the gains are well on their way back down before the amperage blows the emitter. So, with such extensive testing already on record (thanks djozz! :slight_smile: ) why is there a need to keep testing?

If you’re one that just needs to see it to believe it, by all means go for it! LEDDNA will happily sell you all the emitters you care to try/fry. At the very best, you’ll wind up like me with some 90 lights on the shelf and the urge to build more. :stuck_out_tongue:

No i haven’t seen that but i want to, and you wanted to see that before you did so then you know exactly how i feel :wink:

The XP-L you had at almost 7A didn’t show much signs to slowing down or losing output at all, and as you say they always losses output before they break.

Did you really lose 8 XM-L2 when DD or FET driven on copper DTP? because if that is the case it is the first time i have heard about something like that on BLF. In every other report it has always been buck or boost that has pushed it to hard, several here have claimed that when DD like this, it should be self limited by the low voltage in a single battery.

You say that you have found & djozz (thanks djozz i have referred to your charts more than i can count :laughing: have documented, but djozz tests his emitter in steady state from low up to very high. That is not the same thing as clicking the switch & giving the led 7A or more directly, that is a very big reason why your tests often show much more lumens than his charts would show is possible.

If we really are going to know what is possible in a flashlight we need a similar chart but with 1A,2A,3A,5A,7A,8A…… separate tests from a cooled off state exactly like you tests, when you build something & press it for turbo & get a higher reading. Because that how we (at least I) use a hotrodded build, i charge my batteries to full & press the switch for max (from the start) light in the dark :slight_smile:

@djozz if you read this please don’t take this as criticism for how you are testing because i don’t mean it like that 0:)

You jogged my memory and you are correct. I lost those on a TK61 which was a buck driver set-up. The only time I’ve had issue in a direct drive single cell situation was on an aluminum star, the emitter came on, started turning blue, and I stopped. When I got it on a copper star, no problem.

But that was then, this is now. The new breed of XM-L class emitters and I’m told XP-G class will not go this far before dying. They have higher Vf so they might not fry on a single cell set-up, I don’t know. Best I’ve seen from these new ones is just shy of 5A.

This is largely why I like the XP-L now. It still acts like what I’m used to.

And you’re right about the output and how I test. I build a driver, bypass all resistance as much as possible, then test it. Some say my results are not typical, but I say if you do what I did you’ll see the same thing. And does that first start-up output count? In the middle of the night, damn right it does! If you measure at 30 seconds, then again at 60, and 90 and so on, you’ll see that it’s a constant change. So I take it from the top and go from there. Usually also say what it’s doing at 30 so that drop can be seen. In a small light, like my Texas Poker drawing over 3A from a 10440, 30 seconds in the cell is well on it’s way to dead! lol

Fire it up! Go for it! :bigsmile: