High Efficiency BLF Switching Driver? - Request for Desired Features

Hi BLF,

As many of you may know, I've built a variety of different drivers, all fairly complicated and over-driven, compared to regular, sensible drivers .

I thought perhaps it may be time to build one that's a little more sensible and accessible to everyone, well designed, and have some extra features over stock drivers.

Currently the idea is to create a open-source, efficient BLF buck-boost or switching driver.

The candidate target is the FW3x or 17/20mm form factor, and the goal is to design the driver so that it uses open sourced firmware like Anduril or similar, and be designed to be easy to assemble by hobbyists. This way all firmware for the driver will be based on existing designs, though this means it may not be able to support other outlandish features from my other flashlights. However, considering that the FW3A is a FET+7+1 driver, it looks like freeing up 2 pins will allow additional improvements, such as better auxiliary front lighting control, better thermal control, or something else. I'll however leave the firmware to folks who know better such as TK and the rest of the community.

I'm sure everyone here has a much better idea of what features would make a good driver, so I'm asking if anyone would like to contribute to a 'dream-list'. Obviously not all requests will work together, but I hope to be able to collate a nice feature set, and then design a nice driver from the distilled results.

Here are some preliminary ideas to kick things off (will be updated as we go along)...

  • High Efficiency Synchronous Switching Topology
    • Boost mode operation (e.g. with FET, with my caveat that I'm not a fan of unregulated FET drive!)
  • Minimal of 1S operation
  • 3-5A constant current regulated output, no PWM
  • Ultra-low firefly mode
  • Open-source BLF firmware
  • PogoProg programmable from bottom of driver
  • Designed to be as easy to assemble at home as possible

Finally, I understand that there may be variants of this driver, for example, if designed specifically for FW3x, then it will likely have slightly different feature set than say a 17mm driver for Convoy flashlights.

Or perhaps a driver like this exists already and I don't know about it.

Cheers everyone.

I would like to see a 4 amp top end for trips and quads.

I’d love to see a good reliable buck-boost driver for 17mm (most common) and/or 20mm size. The real killer feature would be to port Narsil and/or Andúril to a more modern and powerful MCU, so we have a modern base to move BLF driver designs into the future. ATtiny85 chips have served us well, but we’re at the end of their capability and needing more, especially more channels, now that we’re into CCT mixing. I realize that multiple output channels like FET +N +1 aren’t needed for a good buck/boost driver, but if you’d do this for us, it would be the greatest “feature” you could offer in a driver. Along that line, a great actual feature for the driver would be multi-emitter output, such as color RGBW and CCT mixing of cool and warm whites.

My biggest feature to request is that this exist, and fit in a reasonably small light.

I don’t even need Anduril, if this can nail a good Olight/ThruNite/Acebeam type UI.

Please keep it at 3 amps. Increasing the output by 33% makes the design 78% more difficult. And don’t be afraid to take it lower than 3 amps. Trying to fit inductors and mosfets that can handle the demands onto a 17mm disk is by far the most difficult part.

I am excited to see what you come up with.

Yeah, just keep it at 3A max.

Interested. I’ve got a big soft spot in my heart for both high efficiency and flat regulation.

3A is fine for me.

Is there room in the FW3A for a big enough inductor to achieve good efficiency?

Support for Anduril and Bistro (for clickies) would be superb if that can be made to work, but the basic UI priorities are for me are short click to turn on/off, good mode spacing, and low moonlight.

If a 17mm version with decent mode options like Bistro becomes available, I’ll replace the drivers in my Convoys.

I want zebralight efficiency!
Seriously though, if I could buck drive my Luxeon Vs with a single cell…

I think moderate power at 17mm is by far the most important. High power in larger sizes could be interesting.

I’m curious what the response is on this, but as far as I think I understand boost/buck drivers, each channel would need its own inductor, which would be a problem for size and perhaps also for price. Perhaps that could be worth pursuing for 2-channel tint mixing, but I’ve got a strong suspicion RGBW is a bridge too far.

Either way, surely that’s a future project. What’s being described already sounds like a great step forward for the flashlight community.

I don’t have inputs, I’m just subscribing to see this happen :innocent:

Sorry, I maybe followed my own rabbit trail too far and forgot to come back. All I really meant to ask for is that he port Andúril or Narsil to a MCU that has enough channels that can be PWM’d for RGBW and CCT mixing and other multi-emitter options for future BLF drivers. It was a software “feature” request despite what I actually said above. :smiley:

Anduril can do tint mixing and Toykeeper has the 1634 working. It would be interesting to hear if Gchart has one series firmware working for both clicky and e-switch lights.

Tint mixing for a buck/boost driver doesn’t seem like it would be any fun. There’s already extra components taking up space and making heat and now you need to make it a multichannel design. Cramming two switch converters on the same small board would make a lot of electrical noise and heat problems, going to smaller inductors to make space would mean even more heat and less efficiency.

Maybe its not so hard for Lone Oceans, but I can’t see it being done on that size board.

Yeah, I know Andúril can do CCT mixing. The LT1 project uses Andúril. I want a port so future drivers can take advantage of more than just 3 channels of hardware PWM for CCT mixing, RGBW, and other interesting things the BLF community might come up with. Consider the possibility of two or more output channels, each having at least one high and one low channel from the driver (think FET+1) or more (FET+N+1). I’d love to see this come about. We need firmware support for the hardware to be useful. A buck-boost driver using Andúril or Narsil can already be useful without all those extra channels. But if loneoceans uses a MCU that supports several hardware PWM channels for this buck-boost driver, and ports Andúril or Narsil to it, then others can take it from there. Loneoceans doesn’t even need to do the multi-channel part on this driver, because a buck-boost doesn’t need that.

Subscribed. I would love for this to work with a prog key.

3amos are fine but in 15mm and 17mm would be awesome

Subscribed.

Thermal regulation
Cct mix control if possible.

How efficient can a buck/boost be these days? I thought the extra components chewed up enough energy to make it not worth doing.

It does seem to be the perfect driver for Clemence’s latest project. Nichia NF2W757GR-V3 [GRV3]

I’m trying to find a good way to run one of those emitter boards off of a 2.5a usb port, hoping to put it in a cheap 10 watt floodlight housing. This might be the perfect driver for it.

How hard would it be to put the mcu on a smaller board or make it so a different mcu on an adapter board could be soldered in place of the original?

Set it up with the 85 as a base, and have the ability to use the 841 and whatever you wind up using for the sound activated driver and the microphone. Or maybe check with Toykeeper to see how she’s doing with the 841 and skip the 85 altogether.

The FW3A might be a bit of a challenge for you. I does not deal with heat that well and there won’t be much height for the inductor.

3 amps? C'mon!

3 amps is pretty run-of-the-mill. What's the point? I think current output should be stretched as much as reasonably possible before exotic or too expensive components need to come into play. Maybe I could know better but I think letting it handle some more current (like 6 amps or up to ≈20W stock) can make it fit a broader design and user base without making it too bulky. Corners can always be cut at a later date is what I mean. O:)

Current output can always be adjusted by swapping the sense resistor anyway.

I think Toykeeper can already do most of that with the 1634, someone just needs to make the driver. Lexel’s new buck converter design is probably perfect for it. Four channels of buck/boost won’t add that much runtime. The user interface might get a bit crazy, its a lot to do with one switch. Maybe an accelerometer seeing a sequence of moves could put it in the correct setup mode. Add in a crystal for more accurate click timings if need be.

If someone were to use that driver in a Q8 with a four channel round version of Clemence’s 36 x 3030 mcpcb it might be the ultimate flooder.

Mike C did 1634 driver years ago where every 7135 was on its own channel. Output was controlled by turning on one 7135 at time. Once Toykeeper isn’t stuck fighting for space with the 85 development pace will start to pick up. And its about time we moved on from the 7135. L.O.’s constant current driver should help move that along.

Narsil/Anduril on an efficient buck/boost driver with good firefly mode, can’t think of anything i’d want to add to that.

You mean aside from being a replacement for the 7135 based drivers you tell people to replace?

Well, from the first post: