I avoid posting anything relevant if I’m not 100% sure it works, that’s why there are just some pictures here. I actually have worked some more on it, but I managed to kill my XHP50.2 within seconds, and now I haven’t ordered another one, and I have other more important stuff to do right now.
If you write me a PM I can send you a picture of a schematic.
Hey Snovotill, I have a page written up for my older GXB17 project here: http://loneoceans.com/labs/gxb17/. Like Schoki, the newer GXB172's page is still in progress :)
Nice update, thanks loneoceans. I see your RC at pin 18 has some unusual values. Is that compensating nicely for the high-side sensing via INA139?
I’m building one of these synchronous boost converters into my Coleman remote-phosphor 1500lm camping lantern. Lanterns seem to be lagging waaaay behind flashlights in terms of technology, probably because the average person has no idea about efficiency and battery life. I’ll be adding current regulation to one of these for that purpose:
“TPS61088 QC3.0 Boost Board”
https://www.ebay.com/itm/TPS61088-QC3-0-Boost-Board-3V-L-5V-9V-12V-98-High-Efficiency/272470324300?hash=item3f707f344c:g:UYoAAOSwZb5bMEKO:rk:3:pf:0
The COMP pin (18) is the output of the internal error amp in the TPS61088, where a few passives can be used for loop optimization. See the datasheet (pg 17/18) on how to choose those values. As is, the GXB17 with this topology works just fine but I prefer the simpler and cheaper implementation in my GXB172 driver which removes the digipot. The TPS61088 breakout board you linked looks nice, good luck with your project!
…but but but, how about in stead of buck and boost in one driver, have buck and linear in one driver?
Buck for fully charged Li-Ion, and go to linear when the battery voltage drops?
Would be nice for modern low Vf LEDs, and i assume simpler than buck boost.
(Just a thought)
But while i’m thinking out loud here, linear boost could be interesting too.
For high Vf LEDs or for LiFePo, CR123A or 2x AA batteries.
I’ve been thinking about that as well.
Resistor~~buck~~>linear->FET. Going from super-low to super-high with good efficiency at any mode.
You could take that one step farther and also eliminate the synchronous boost regulator. The old-school cheapo unregulated LED flashlight circuit shown below could be regulated by varying the DC bias into transistor M6 via the MCU D>A or PWM output pin. No need for a schottky diode so long as your inductance is large and so efficiency is very high. You'd need to sample the flyback frequency and battery voltage to determine actual LED current.The flyback frequency is linked to the hFE of the transistor which varies with operating temperature. hFE of course determines the peak inductor current in each cycle. I know it's not practical due to physical inductor size, but it's an interesting concept which would work for up to 300 lumens or so.
Hey, the drawing you see below is a base-64 encoded image stored directly within this post, so it will still be here a hundred years from now ;o)
Why not just make a buck-boost-linear-fet-dd driver with built in microwave?
a DIY kit for driver flashing
I like the microwave idea …
Jokers….
Once you have a simple low-power buck driver, adding a FET-based linear driver is a matter of like 20 extra components, mostly passives. That’s not a small change. Adds some board space, but not terribly a lot - LD4 is single-sided 17 mm and these components take about half of its board space. May require use of a MCU with more pins than the old SOIC8 ATTinys have. For that effort the payback is much higher regulated output as well as longer regulation.
Once you’re there adding unregulated mode costs nothing and pushes the peak further up.
And then adding a resistor cheap and reduces moonlight to ultra-low level.
Overall: Complex. Expensive. Unlikely to fit on a double-sided 17mm driver. But:
- peak power is top notch
- peak regulated power is top notch
- bottom power is top notch
- efficiency is top notch
W/out the buck driver, the points 1,2,3 would look the same in a simpler, smaller and cheaper driver. But efficiency at low modes won’t be top notch. So I view that as the high-end choice for 1S 3V lights where it’s not too large….which is quite a lot of lights.
Did he mean WiFi?
The following is of course just an opinion. Take it, build upon it or leave it.
Lots of people here are keen with the MOSFET driver idea. Such idea is not a fit for everyone or any case. It is unregulated and overall limited, and requires careful assessment of all components as there's chance to make the emitter operate with too much current (past optimal zones) or even fry it. Of course I can understand the people here aims for hybrid drivers, but this would require for the driver to know when to switch operating modes… ( ͡° ͜ʖ ͡°)
As far as I understand the MOSFET thing is clearly superseded with a proper linear design, a MOSFET linear design like led4power designs or the LD-25 (reviews: there and here). I also gets rid of PWM annoyances.
A proper linear design uses a suitable MOSFET and a current sense element. Selecting a proper tiny value current sense element is key, notice how the latest LD-25 does with just 10mΩ. This is key for high power output. Since dissipated power at the sense element is P = I² × R even smaller values may be due.
Anyway, I'd say the best option is a buck boost design. If you really like to go nuts and “fry” your emitters, oversizing the components and removal of the whole constant current logic could be done for regulated drivers, and leave you selecting desired output voltages for the different modes through some way like adjusting current in LD-25s (a constant voltage supply).
Cheers ^:)
It seems there’s some work on updi in avrdude:
https://github.com/facchinm/avrdude/search?p=1&q=updi&unscoped_q=updi
I see on avrdude that some people are using it though I fail to understand the details.
Maybe missing PIC microcontrollers' love: programmers, people making ports of existing code for other chips and such.
Plenty of PIC micros in many drivers.
Regarding software names, calling software Anduril or Narsil just sounds @#$% to me. I prefer descriptive and senseful terminology, plus detailed version numbers.
Are there any 15mm drivers with Anduril installed?
There are some TA 15mm designs that could have anduril flashed to them.
Lexel most likely offers them pre-made as well.
Hum, what do you mean by pre-made? Ready to install the FW? I don’t know how to install it and have no means install the FW.
Also, another question about those TA drivers: do they work without the 7135 chips in the bottom (spring side)?
I have some lights in which I could use 15mm drivers with only the spring (or no spring) on that side, as the chips would interfere with internal space/battery.
Thanks for the reply in advance!!
It should be able to work without the bottom side 7135’s but would need the right mode group selected to do it.
Lexel makes drivers that are ready to install in small quantities.
I generally don’t bother with making drivers to sell unless I can sell at least 25-50 of it, just not worth the setup time for less then that personally.
Thanks for your reply TA! I get what you say, and I would need to check with Lexel if he could make those drivers as it would imply more work!
I also know that MTN has those flat sided drivers ready to install, but I didn’t see them with Narsil or Anduril, only the Ramping IOS from the D4 on them.
Thanks again! :+1: