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

From MtnE front page:

:slight_smile:
I wonder when there will be Narsil though.

guppy should be fine for clicky lights, at least we have more progress

I would also be interested in purchasing 17mm boost drivers. Maybe a few larger ones if 17 is not possible.

You will need to see Lexel about that. I just recently heard he got some help to get NarsilM working on his high powered boost drivers. No word on when they will be available, though. I hope soon.

Iirc, Richard doesn’t use NarsilM. He may adapt RampingIOS (the D4 UI) to work later on, though.

To show I’m working on it:

So, do we need to take up a collection for you guys? I’d be happy to throw in a couple bucks to push the boost driver forward. I figure there are others who would do the same.

Indeed

[quote=The_Driver]
There are a few that I want.

1. 1S Buck-Boost Driver for 2.8-4V LEDs which does up to 5A, but it configurable down to 3A. Controlled by eswitch with many low modes (like Zebralight), overtemp and overdischarge protection. Maybe also a version for clicky switches. [/Quote]

I just found out here that Zebralight used the TI TPS63020 buck-boost IC in the SC62. It does up to 3A from a single Li-Ion.

I would love to have a similar driver as an aftermarket part, especially with an even higher led current.

This TI chip can go down to a Vin of 1.8V, so it can also be used to drive UV LEDs (at less than 3A).

The TPS63027 looks like a good candidate because it can deliver a high output voltage of up to 5.5V.

The MAX77816 might be another good option. It can deliver 3A in boost mode.

I would be looking for a 1 cell boost driver. But I just started building and flashing my own drivers, therefore I am not a useful contributor or not to the extent like the pros on here.
Not sure which emitter should be used either, maybe a 6V one and some good amperage behind it (around 2A-3A maybe?).

Boost and buck/boost drivers are the future IMHO.

We have reached the max of what we can do with a single 3V LED with 1S input some time ago from a driver standpoint.

Buck only really works if you have a higher input voltage then the LED (aka, 2S for a 3V LED, 3s for a 6V LED ect) and this is not generally possible without making lights un-necessarily large.

I would be happy with a 2S/2S2P/3S 12v. boost driver for the XHP35/70.2 12v emitter @ 2.5-10amps in a 22-42mm diameter, that could take the heat and be reliable.

No, Bucks do actually work with today’s 3V LEDs, just not for the entire runtime. That’s why buck-boost is great.

The problem with buck-boost is it requires more components. The extra components use more electricity reducing efficiency and makes it harder to fit everything into a flashlight sized driver.

By the time the boost part of the circuit gets used there is so little energy left in the battery it barely offsets the energy wasted by the boost portion of the circuit while in buck mode.

True. It really depends on the LED you want to use. Buck-boost is good for lights with single high-Vf LEDs and a single Li-Ion cell. Buck is good for low-Vf LEDs. Linear is good for medium-Vf LEDs.

Some high-Vf LEDs: Cree XP-G2 (especially the S4 2B), Cree XM-L2, Cree XP-L, Samsung LH351D and the Osram Black Flat.

Great but, are you planning in somehow making this driver available to the DIY community? If so, let me throw in a few comments (bear in mind I've barely read anything in this thread LoL):

  • First of all, hope to see the driver in fully assembled form. From a DIY standpoint I can't see myself having a lot of fun having to pan reflow one of the board sides to later use a hot air gun for the other side while watching for components not to fall from side one over the table. Of course, I may have dramatized a bit, it is just to stress the kind of scarecustomer challenge it can be.
  • I am seeing large inductor pads. This means having to apply massive amounts of heat over the board in case the inductor is to be replaced. Can live with it but can't say I fully like that. Hope it helps with driver heat management.
  • Hope you are using a tiny sensing voltage, tiny enough for sense resistor heat to never be problematic. Improves efficiency too. Did you tried sensing voltage drop at the switching MOSFET? :-)

Cheers ^:)

A single cell buck/boost might work, with 2A maximum. We could put 2 of those in parallel to decrease conduction losses. Current-Sense Amplifiers that could be used for this are available.

Buck converters could be possible with low-Vf LEDs and an “oversized” Buck-IC (which is made for more current).

When you solder a board like that do you do one side with high melting point solder and then use lower temperature solder on the other side?

How close is this board to being the final version?

Yes, making it available for DIY is the plan, and it always was! I will try to make it like the TA-drivers.

Building the driver is not easy. But not in the way you describe it. The parts won’t fall off, you really would need a lot of time heating up the board to melt the other side, and even then, the surface tension of the solder should keep everything in place, except for the inductor.
The most painful part is to place the solder paste and the parts. It is a nightmare, because I don’t even use solderpaste stencils, I do everything with a syringe and a toothpick!

With the inductor, I may actually change the plan and use just one for both 6V and 12V LEDs, but let’s see how it turns out. You can somewhat “shield” the other parts with some aluminum foil or kapton tape while heating the inductor (the aluminum foil works pretty well with an IR solder station (which I was able to use once, and its way better than hot air)).

I’m using a 10mΩ current sense resistor, that’s 10mV/A. At 6A, that is 0.36W of heat. Sensing voltage on the switching FETs is possible, but not a good way. The resistance changes too much with the temperature (a bad characteristic from Silicon), and the next problem is that their switching on and off. Sensing at the inductor (with an RC filter) is the better idea, until it changes from PWM control at high loads to discontinuous mode at light loads. Then you can’t sense the current anymore. And the inductor current changes with the cell voltage.

Pretty close (I hope). The plan is that I will reflow one this weekend and see how it works.

But why shouldn’t 3A work? Zebralight and Armytek managed to do it (for years now).