I was thinking the other day, that its surprising we dont have a wireless charging driver in the aftermarket/moding world.
I would love to see a simple solution for wireless charging.
What do you mean, inductive charging like a cell phone? I don’t think it works through metal. So you’d need a plastic flashlight. :confounded:
Not exactly.
He probably means something like in the tailcap.
Would not be good for charging efficiency though, along with speed.
@Jason, he is using top of the line GAFETs. These things are absolute beasts for their size, since their working internal resistance(not interconnects) is much lower than traditional MOSFETs.
So yeah, it is a beast of a driver.
Now that the FW1A is out, I’m really hoping a more stable driver like this comes to fruition. I’d love it to be able to drive a beefy 12V XHP35 HI, but even steadier output at 3V would be awesome.
So your talking about small drivers like under 22mm? I recall that burnt traces on the pcb tended to occur when the amperage go too high. I don’t think the gafet would have any effect here. Maybe he’s using more expensive really thick traces?
Not really actually.
See here:
Nice project!
My suggestions, well, preferences would be something like the following:
1/2S - because I'm thinking about the 2 * CR123/16340's mainly and 2 * 18350 compatibility (the CR123 primary Lithium's because of their shelf life and the 16340/18350's because.. they just fit, so.. why not)
I'd say a buck only driver would do just fine ? Although I've no preference if it'll end up being a buck/boost and taking anything from Alkaline primaries to Ni-Mh/Ni-Cd and up to 2S Lithium secondaries..
Efficiency and the a BLF UI like Anduril ? "Of course! I'll take two!" (well.. maybe a couple) Myself, I'm not aware of any Buck, Boost, or Buck/Boost driver/s running Anduril, Or Narsil or such FW's.. Are there any ?
Simple bi-color LED Batt. Lvl. indicator on the driver's PCB that would be lit Green > Lime > Yellow > Orange > Red > Blinking Red when the light is on, for either 5 seconds from On, or constantly On.
I know that there's a voltage indicator function in the Anduril or Narsil FWs, but that's only accessible while the light being powered Off and not really user friendly and seamless for the average non flashaholic.
Not interested in over 3 Amps myself or direct FET drive for Turbo, I'm more interested in being able to drive something up to a regular XP-L/XM-L and down to an XP-G/XP-E without the risk of frying them.
Also interested in having control over the max current, as previously mentioned, via shorting some pads on the driver (shorting serial current sensing resistors I'd take it ?) - Something like 1/1.5/3A maybe ?
As for the size, I'd say a common small size like 17mm would do just fine and also make some adapters like the Convoy 17 to 21mm adapter, but for more commonly used sizes, up to 28mm ? Or.. even cheaper..
The way I've fitted a 17mm BLF A6 driver to my Civictor T5 20mm driver, was taking a 20mm tail switch PCB and since the BLF driver was single sided as well, I've just sandwiched it on the switch's PCB..
So I'm thinking maybe you could make this driver single sided as well and some PCB adapters in different sizes with only the spring pad and a hole in the middle to make it easier to bind/solder the two of them ?
USB charging - I don't think this would be feasible - for starters, because as you've mentioned, there's no USB port cutouts on most hosts and also fuel compatibility would be limited to 1S (?)
About the temp. sensing.. not sure about the external sensor - I could do with or without it as long as the sensor in the MCU is decent enough - After all, the general consensus was around 3 Amps tops ?
Also about the temp. sensor calibration, I'd say the "hold until hot" route would be making the factory calibration irrelevant anyways ? As we'd only be interested in the max temp. that we'd be comfortable with ?
Not sure if this would be FW only related, but could we have a LVP cut-off Voltage configurable from ~2.8V to around 3.3V ? Some would comfortably run the cell dry, and some would be wary about the voltage.
Thanks everyone for the great feedback! Please keep them coming, and watch here for updates 
3.3V cutoff?
If the aim is to be able to utilize as much energy from the cell as possible a high cut-off is completely undesirable. I must also say that, according to my experience and corresponding beliefs, (little?) nothing is to be gained with a high cut-off; maybe a small stress reduction for the driver, if anything. Since the actual voltage input into the driver is cell voltage minus path (springs, switch, etc.) times current voltage drop, I would instead lower the cut-off even more if possible, to 2.7V or just the lowest driver feasible and li-ion acceptable figure (like 2.5V).
This is not at odds with 80T's suggestion anyway.
Just my point of view, of course. 
I'm not sure what the goal is regarding yields per cell, but I know one of the goals it's power losses cut-down, efficiency, thus, for any given capacity this driver should waste less power than a linear one. Where a high cut-off wouldn't make sense at all would be when using primaries, although if the driver would be recognizing cells by voltage, then we could have cut-offs by cell types. My opinion is that the more option, the better. Myself, I just don't like to run my cells dry.. usually.
About the current path losses, with some decent springs and this driver not being high power, I'm not sure how much would that be a concerning if at all relevant factor.
Subscribing! My 2 cents…
Output: I’m probably in minority here, but I fully support the 3-5A limit. I much prefer a constant current output instead of the FET “wow” factor that gets the flashlight blazing hot and then needs to step down right away. Sure, 3000 lumens in a tube light is neat for 25 seconds, but give me 1000 lumens for several minutes any day. For this, our traditional 7135’s aren’t bad, but regulation is limited by the voltage drop and their linear nature (no buck/boost). I’ve also used the QX7138 lately with an external FET - so far, so good, but I haven’t fully tested them yet.
Programming: I really like the simplicity that 3-pin UPDI programming brings, but that’s limited to the newer AVR chips (0 and 1 series). While I (and Mike C) really like those new chips, we’ve otherwise seen almost no traction in their adoption. It’s too bad… they’re great to work with.
I do have firmware rocking for e-switch lights using the 1-series. I’ve got some custom stuff written, but I’ve also ported TK and Tom E’s excellent RampingIOS over and it’s working flawlessly - I’m using it in my Convoy H1 (stock driver with new MCU), Emisar D1S (custom driver), Sofirn D25 headlamp (stock driver with new MCU) and others. I also hope to have Anduril ported over soon-ish, but I just need to get re-engaged on that effort. As far as clickies go… I just designed a new clicky driver using the 1-series, but found that I couldn’t use our tried-and-true noinit trick to detect fast presses. The SRAM was taking around 45 minutes to decay instead of the ~1/2 second that we’re used to. So in order to use the 1-series with a clicky, you either need to use on-time memory (yuck), OTSM (as Mike C is doing), or an OTC. To be continued…
So I have an idea/suggestion for simulating the benefits of having like 8x 7135 with just the FET. But it’s so simple I don’t know why I haven’t seen talk of it.
Currently if you want to maintain a brightness that’s 60% (of maximum), you stack 8x 7135 and send them a 60% PWM signal. As the battery voltage falls, the 7135 maintain a constant brightness down to 60% battery.
Well space is limited, so why not do it like this:
Let the code monitor battery voltage. If the battery is fully charged, PWM = 60. If the battery is 60 PWM = 100%. Now for smooth transitions you want to use a multiplier instead of just if/then statements. And the perception of brightness comes into play. But with the extra code space of the new drivers, this seems quite feasible and should free up a LOT of board space on the drivers. And lower cost.
After reviewing this thread again…. I only have a couple of relevant thoughts.
First off, I know you are going for sensible… I think that would be about 3 amps in a single and I really think more like 5 amps in any triple. 1 amp per led will not get most of the crappy emitters even close to out of the green!
Second thought… I think a 1S design would be ideal. Now, if possible a 1S/2S could be handy if one could dump in lithium primaries or for example a pair of 18350’s if need be.
Have been watching this discussion from the start, really hope it goes somewhere. I for one would use it in my EDC FW1A and FW3A.
That seems viable, but is a distinct concept from what loneoceans is proposing.
Another concept is the LED4Power drivers. I’m not sure how exactly they manage it, but they achieve a non-PWM output, and some of their versions have fairly high current ratings.
Yea, it’s different, but I thought of it while reading this thread, so I shared.
I don’t know anything about LED4Power drivers, but from what you stated, I imagine they use a very high PWM frequency, then maybe even feed that into a capacitor to go analog.
Both Led4Power and the latest drivers available at the Convoy store use MOSFETs as linear regulators. They use their microcontroller to monitor the voltage drop at a sense resistor, and according to this they precisely tune the MOSFET gate voltage for it to exactly drop the required voltage delta. This means the dissipated power at the MOSFET is voltage differential times current, being this the main driver hurdle (dissipated power in MOSFET and driver, nothing to do with amps rating here). (^̮^)
Ah, that explains why he talks about being able to dissipate 15W if you use a seperate FET board.
My deepest dive into circuit design, not being an electrical engineer, involved accidentally dissipating too much power in a FET, due to not having a pull-down resistor to drain the gate voltage while PWM’ing it - the FET was spending some time every cycle with its gate voltage in an intermediate, partial on state. I burned up several FETs this way before a tech helped me figure it out.
My experience makes suspicious of that approach, but I could see it work if there is an appropriate amount of cooling.
(Generally speaking) This is only true if you are talking about a linear 1 amp. If you pulse a FET to create a 1A load your tint will be closer to what you see if the FET was on 100%, like 6 amp or whatever. It’s because you are literally getting a fraction of that 6A. So it does matter how you get that 1A.
JasonWW, I would think so too, but look at the 219b plot in my signature, the tint is wildly rosy with the FET at 100%, but not similar when it PWMs.
My statement above was pretty general, like for most leds. Maybe the 219b is an outlier. The A6 driver is FET+1, so Med level is definitely using the FET. If you are a person who wants to build a light that keeps the green away you would probably want it to have a FET only (or FET+1 if you want very low moonlight levels) and then match it up with the right led, probably not a 219b. I wish I knew more about the subject, but I only know a few things. Lol