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

Is there a blf style buck driver (good, customizable UI ), that can do 2s input and have 8-11A output for 3v led?
The MTNmax buck stops at 5.5-6A.

With some of the newer leds they dont really stand out from the crowd till they hit 7+A.

I have such a driver in 30mm based on BLF GT design, the boards arrived yesterday

shrinking it to 22mm wont be possible with the limited choice of the MOSFET

I have a small problem reading this OpAmp datasheet here: https://datasheets.maximintegrated.com/en/ds/MAX9617-MAX9620.pdf

To be precise it’s the “Output Voltage-Swing”.

There are multiple values given in the table with various resistor values, but when you scroll down to the graphs, there are two called:

  1. OUTPUT-VOLTAGE SWING HIGH vs. TEMPERATURE
  2. OUTPUT-VOLTAGE SWING LOW vs. TEMPERATURE

Now these values from the graphs are much lower than those from the table. For the “table values”, there is a resistor RL connected to the OpAmp, but I don’t know how it is connected.

Is RL connected between the output and VDD/2, to show how near the OpAmp can get to the rail with a load on it, and the graphs, when there’s no load?

I am far from an expert in data sheets but I have learned that the graphs generally do show better numbers then the official ratings. This is due to the built in error margin that the companies build in the way I understand it. Also most of the official ratings are max ratings, so what they guarantee the components will not go over.

Thus the real world specs can generally be a fair amount better in most cases and these are what you see in the graphs.

In “real” manufacturing they design off the max ratings and then just get a nice bonus if the parts preform better.

Also I noticed this at the top of the graphs page :

So looks like it has some resistance connected in the graphs as well.

But there is such a huge difference, 11-12mV compared to ~0.3mV

Yeah, I am not sure this is the case, just my best guess. I have seen pretty big differences before and the ratings are listed as max ratings. But that is a bit extreme I admit.

The new 17mm high-power boost driver will open up some interesting possibilities for triple lights. It will be possible to use high-Vf LEDs like the Cree XP-G2 and Osram Black Flat in a triple configuration with a high current through each LED.

Yep, I plan to swap out the driver in my EDC with this one for just that reason. I still have a hard time finding a better tint then my mixed tint EDC. Although the 90CRI XHP50.2 I have been playing with looks promising, if I could find it in 4500k it would be perfect.

Why is xpg2 so interesting when we have xpl hi, nichia, sst40, samsung, luxeon? What am i missing here?

Not sure on the XP-G2 in a triple, I have xp-G3’s in my EDC right now as they provided the best high CRI tints I have found so far.

I have high hopes for the XHP50.2 though, early tests say it should be able to give around 1500 more lumens OTF compared to my existing setup and have technically higher CRI (mine is around 85cri right now).

If I could just find a 4500k 90CRI xhp50.2 it would be perfect based on tests with a 4000k and 5000k 90CRI xhp50.2.

It has a higher luminance at the same current. Instead of 7A you can drive it with 4A for the same throw.

It has a higher luminance at the same current. Instead of 7A you can drive it with 4A for the same throw.

As LD-40 is discontinued, there is currently no buck driver for red leds running from a single li-ion cell. (In the hobbyist laser land, they have flexdrive for current upto 1A) It is really a shame since efficiency of red leds keeps improving and we still drive them with 7135s. I have plans for building XPEEPR (deep red, 51% wpe) triple using a Sofirn C8F and run it at 2-3A.

I have searched a lot on TI, Linear, Onsemi - the best chips are made only for CV type application (2.5V rail), LTC3561A and LTC3612 are very promising. To design a pcb from their app note is a huge challenge for me (could take a year), because I could not just copy the app note circuit, I also should use another fet and mcu to support momentary switch and modes!

EDIT: Maybe using an Ledengin lz-4 (4 deep red dies in series) in a Convoy L6 is a better way to go, but that’s too expensive.

I plan to make a buck driver for an EDC build for myself (after I finished the 17mm boost circuit). I could make a 17mm version as well. It would be 1S only though.

Do you plan to make a boost driver for XHP35? If so, will it boost from 1S, 2S or both?

Yes, and both :+1:

Very nice :beer: . What max current do you expect?

roughly 6A with 6V config, up to 3A with 12V config

Waiting impatiently :wink: ….

Will it have the custom firmwares normally used here?