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

Yes, 20mm and 22mm are sizes I use a lot. 17mm doesn’t interest me much anymore as aside from my P60 drop ins almost everything has now been bored out to accept 20mm.

I could use a bigger one with attiny85-sized SOIC8 or flashing pads/vias for development purposes… doesn’t have to be used in an actual light, but convenient reflashing would help a lot with adding support for the hardware.

Oh, um, probably also large pads for an e-switch. Small pads break off easily when the driver is air-wired and gets moved around a lot. Again, for development purposes only.

Thinking About It.

(pic taken two weeks ago at my friend’s house)

So you mean some kind of development board? So doesn’t even need to be round? I would make one with bigger pads, vias (or pads as well) for flashing, some “wire loops” (don’t know the name) to get an oscilloscope connected. Maybe there’s a way for two ATTinys, 85 and 25v, and just with a switch (or a few) you could switch between the most used MCUs for different firmware. Or some kind of breakout board (like on Arduino) with one of the MCUs on it, and you could swap them.

With older driver designs, a dev board wasn’t relevant because it had plainly exposed pins with room for a clip. It’s only on newer denser boards that it matters. But yeah, a dev version would probably help with getting code support.

Once the hardware is understood well, development for this boost driver can be done on a one channel fet driver. It's just for testing the low modes and making sure that voltage control works out where the real thing could help initially as I see it.

This is like a “name your wishes” thread, I like it :smiley:

So, my first wish:

- buck driver,

- up to 20-21 mm (or 17mm even better, maybe two board design)

- 8.4V input

- output for XML/XPL 3V leds

- up to 6A

- based on Tiny13A so I could load custom firmware

- 2 switches, forward clicky for on/off and electronic switch for changing modes

  • from: oshpark or china (sorry, ordering from states is just too expensive)

that would be about it :slight_smile:

5A Buck-boost driver for UT-02 to push this light over 500 kcd.
Reference:
http://www.candlepowerforums.com/vb/showthread.php?440679-NEW-WORLD-ORDER-4-THROW-V54-World-that-is-HaHa\*&p=5161053#post5161053

ADDED:
I haven’t measured if it fits, but buck from 2x26350 may do too. :wink:

I’m contemplating tweaking my Q8 with XHP35 HI.
I’d like something that can sustain as many candelas and as many lumens as possible, so I need efficiency.

I don’t have the skills for such mod yet, but it doesn’t stop me from seeking options. :wink:
2s~~12V boost with XHP35 seems like a natural choice. Or even 4s>24V. Buck 4s12V could work as well, just like boost 1s~~>12V.
Is there anything that would work well in such setting?
I guess BLF GT, but it won’t give good current to 4 LEDs, will it?
Something else?

The BLF GT driver in stock form would be able to drive them at around 1.25A each, maybe a bit higher. If you upgraded some components it could do around 2A each.

Not great, but not bad either. Turbo won’t be as high as possible, but 8A is significantly above what Q8 can sustain anyway. Will fall out of regulation before batteries are half emptied. And efficiency should be good, right?

2A to each xhp35 is where the trade off in lumens vs efficiency starts falling real bad.

You will have a big issue with falling out of regulation though with 4 LED’s and only 4 cells.

1.25A on stock GT driver with 500kHz frequency possible

I am working on an upgraded GT driver
I am discussing with del the needed changes
So far Buck frequency changed from 800 to 500kHz
input and output caps doubled, the design already has pads to fit 2 caps instead one
Diode 3A to 5A
inductor from 6A to 15.5A

6-8A should be no problem to get to
10A might be possible but that’s about the current the XHP35 get not much gain over 2A anyways

Yep, with those changes it should handle 8A. The issue then becomes it falling out of regulation very quickly due to the voltage drop with only 4 cells.

You could get fully regulated 50W output using LTC3119 buck boost with 4S input and 12V output. Around 4.2A output is my guess. Bonus is that lower output power can also be used with 1S or 2S input.

Using 2S input the MP3431 chip could probably give you 8A output fully regulated. I don’t know of any existing boards for either IC though.

If you want to design a PCB there will be some design considerations for heat, especially for the MP3431. Realistically we can assume around 90% efficiency, maybe a bit better, but at 100W+ of output power that is still going to be almost 10W of heat into the driver. Most of this will be between the IC and the inductor. So you will need to design a PCB using the full available driver size, and ensure that the IC has a good heat path to the host through the PCB. Remote mounting the inductor directly to the host with thermal adhesive would also help, and it frees up PCB space as a bonus.

Any update on the 17mm boost driver? Holding out on building a M1 XHP50.2 so I can go single cell route!

I have contacted Schoki to get a 1S Boost driver with Narsil/Bistro done

My current goal is 12V/2A for 17mm and 20-22mm 12V 3-4A

We may go to a smaller MCU to get a bigger inductor and diode for higher currents,
but this complicate things and make building more expensive

Ordered new boards, they will arrive next year. But it should work then, maybe needs some firmware tweaking as well.

17mm BLF 1S 6-12V Boost driver is in progress

This is a very powerful one, not cheap at all, but we target 8A for 6V LEDs, XHP35 can be as hard driven as desired

I got the board made in Diptrace I made improvements

power cap pad sizes increases to a 0805/1206 dual footprint, depending if 1206 fit to the driver cavity
other parts 0402/0603 Footprint
MCU/LDO caps 0805 size to use OTSM cap
and especially the thermal connection of the boost Chip got improved massive using the inner layers with direct thermal path through viases

No place for programming visases so a solder pads or pogo pin connector plate

ignore the 2. ring around it its just for production on a bigger board for easier separation

Really neat work with the implantation !
That big square is the coil I presume ?
I know it’s early stage development but do you have a guess at how how much it could cost once assembled/programmed for a lambda Customer like me ?