LED drivers and Accessories you want, but don’t exist

First try on a 1-mode Buck-Boost converter for 2-3AA or 1 LiIon cell:

It uses a TPS63020. You have to calculate max current yourself (see page 13 in the datasheet), but it can do more than 800mA, even worst case. The current can be programmed via one resistor. There’s a jumper as well to choose between normal mode and low current high efficiency mode (see figures 10 and 11 in the datasheet).

How do the spring pads work? They appear to be seprate from the rest of the underside, is that simple so the IC can be heat sinked with those vias or are they V+ and ground?

From what I see the left pad with the vias is V+, the right pad is floating and is just to hold the spring, and the middle vias go to the ground ring and are there to heatsink the IC.

Jensen567 got it right :+1:

I just stumbled upon a tool to program attiny1616 and other tinyAVR chips:

I’m not that involved into this, how can we program the new Tinys then? With an USB to TTL adaper? How does this work on the software-side to get the code sent to the MCU?

Now this is something more powerful:

This is a 1-Mode boost converter with an MP3431 on a 17mm board, powered with 1×18650 or something similar (max. input current 19A!). Current is set with one resistor, like the 1-Mode buck-boost circuit before (of course you can change the current sense resistor as well).
If it doesn’t get too hot, this circuit could supply (calculated values) up to 6-7A to an XHP50/50.2/70 (the lower the forward voltage of the LED the better), or a bit over 3A to an XHP35.
Heat probably will be a problem, but for short bursts, it should work.

Liking the nice fat copper traces going to the SW, GND, and OUT pins, and especially the nice short path from the chip GND pin to the driver ground ring. In a host with a retaining ring for the driver, or soldered driver, you should get good heat transfer out of it for high current.

Nice thread!
I’d like to see a 10~12mm sized driver for 10440 flashlight with high cri nichia. Preferably e-switch with Narsil or comparable ramping firmware, blinking out the voltage and supporting lighted tailcap. With a true moonlight and direct drive mode. Thermal regulation would be nice, but I think can only be accomplished with the driver behind the MCPCB.

(Being able to run it on AAA as a fallback would be a nice bonus, but definately too much to ask for. )

To build something as amazing as CRX did here Lumintop Tool Ti
but running Narsil would make me a very happy man!

The PyUPDI thing looks interesting. With a need for only 3 pins instead of 6, it should be significantly easier to design drivers which support acupuncture-style reflashing… particularly since one of the pins is VCC and one is GND, so only one actual programming via should be needed on linear drivers. This also allows using physically smaller chips, so more room on the driver for other stuff.

I’m assuming a usb-serial adapter of some sort would work.

It also looks like gcc got support for attiny1616/1617 about three months ago, with a release target of gcc 8.0, so as soon as that’s widely available it should be relatively straightforward to build binaries for those chips.

A proof of concept could probably be done now, using pre-release tools, but the barrier to entry seems a bit high for common use.

Wow, I really like that MP3431, good find!

That has a LOT of potential.

Now that’s serious stuff!

Quad XHP35 HI under Carclo 10622 with well over 4 klum OTF and little under 100 lm/W while delivering those lumens. 1000 lm for 1.5h from a single 18650 cell. Flooooooody.
C8 or similar with dedomed XHP50.2 doing 3500 lm and (???) 100 kcd, sustaining 2000 lm for long.
C8 or similar with XHP35 HI doing 2500 lm and XXX kcd.

My favourite UT02 with XHP50.2 doing 3500 lm and 180 kcd?

And those numbers are conservative.

Too bad that with one mode it needs a big host to dissipate the heat…

TA, if you want to do some development with the MP3431 with your own boost driver series PM me, I can give you some info on the chip so you can have a board ready for when they go on sale, hopefully soon.

You can already order them on Mouser

Yes, this is the best boost IC I have seen so far for our uses, I am sure that I will start playing with it once the next gen MCU’s ave matured. And once I have some spare time again, been too busy to even read BLF the last few months.

Kind of in a holding pattern until those MCU’s mature anyways. The features they offer are good but the most important thing is the size, we simply can’t progress any further with the large SOIC8 MCU’s, there is no room for anything else.

Now if we could just find a similar speced IC for a buck and buck/boost driver we would be set.

MPQ8633B would be the Buck IC with similar specs, I have info on that one too. No high power Boost-Buck that I am aware of yet, but the MP28164 is a 4.2A Boost-Buck chip.

Not affiliated with MPS in any way, i just found their catalog and thought they make some nice chips for flashlight drivers.

Buck should be possible to find, but buck-boost will be tricky…

Both of those are interesting options. The MPQ8633B looks real good but it is hard to tell from the cover sheet, is the output voltage limited to 5.5v? Or is that just the reference voltage?

The MP28164 looks like it would make a great general use driver for small lights as you don’t need more then 4A anyways in most cases. I also like how few external components it needs.

Vout max on the MPQ8633B is 0.9 of the input, or 5.5V depending on the input voltage.

Yeah, thats how I read it as well. Sad it would not work for higher voltage LED’s, if it supported outputs up to 16V like the input it would be great.