Buck and Boost Drivers, Testing, Modding, and Discussion (Pic Heavy)

i believe the Lone Ocean’s driver is finished, just need some more testing( which happens i can help him :stuck_out_tongue: ) and some firmware touching

I belive Schoki will have one in the near future

Finally some MT-G2 6V Love

Sketched out the schematics of the BW-ET1, for those interested.
I hope it’s readable.

So they built a buck-boost converter by daisy-chaining a TPS61021A (boosts to a fixed voltage, 3.3V I think) and a TPS62095 (steps back down to current set by op amp). A small dedicated 3.3V boost converter feeds the µC in AA operation.
The op amp operates more like a comparator that compares the voltage drop across the sense resistor against a filtered PWM output from the µC. No direct feedback, no fixed gain, the converter itself is the feedback loop. (I kind of understand how this works, but I’m no EE guy).

The CC control scheme looks solid but Blitzwolf messed it up with bad PWM.

Efficiency isn’t going to suffer much from this arrangement I think since the buck converter achieves around 95% efficiency. The obvious downside is driver size (humongous).

I’m looking for information regarding the H1-A driver. Maybe someone can help me here.
I don’t know which revision i have. It should be fairly up to date as i bought this driver in november 2018.

a) Does the H1-A feature thermal shutdown?
b) What would be the maximum operating temperature for the H1-A?

Says it does, look on page 6 of the TPS61088 datasheet.

Thx!

hi mrheosuper, do you know where I can find the Lone Ocean driver and the Schoki driver? Is anyone selling them?

I saw a forum member recommend this boost driver. Is there smaller version (20 or 17mm?) around?

https://www.aliexpress.com/item/22mm-6V-4-8A-Booster-Driver-Board-with-Temperature-Control-for-CREE-XHP70-LED-Emitter-1pcs/32940723064.html?spm=a2g0s.9042311.0.0.56884c4duv6jte

This one is 6V 4.8A booster driver.

Looks good but better wait for it to be on sale, right now it is twice as expensive. :facepalm:

The H2-C is a proven nice option and can be modded for lower voltage output and higher current. Or use it with 2S input and 4S output, it should handle pretty hefty power that way.

Cheers :-)

It is on sale now. Otherwise the price is twice as expensive.

Such driver coupled with a suitable host could make a serious lumen monster, I bet it will handle 7 - 8 amps just via sense resistor mod without issue. A couple of examples are the UltraFire F13 and Kaidomain's “26650 Fishing Flashlight Host”. I do not know what the tail switch may feel about that, though.

Cheers ^:)

wow do you know if this will work? What d you mean tailswitch? If the output is 7 to 8A, does this mean the battery is supplying 14 to 16A? I think you are right the switch will melt! What is the best option then?

A MOSFET switch is the best option, but that currently is a total DIY solution. Alternatively:

Cheers ^:)

Mr. Barkuti, i see what you mean. I was looking at loneocean gxb172 driver and found this switch!

https://budgetlightforum.com/t/-/50404

Is this what you mean by mosfet switch? It looks like I can make my own with the files on the page. This looks like ideal solution. The KAN28 is too big to fit in some flashlight tailcap, but the 'small Omten switch" looks like it works OK even at 16A. Is anyone tried making mosfet tailswitch?

Is there bridging that can be done with a H1-A driver to set it to HIGH only mode?

I wish more drivers came with the “simple man’s” bridging stars.

Thanks

This is just a guess. It be better if someone more knowledgeable confirmed it.
In this post Buck and Boost Drivers, Testing, Modding, and Discussion (Pic Heavy) - #20 by Jensen567
Cutting the trace after the 47k resistor leaving the opa333 is my guess. In the datasheet tps61088 it shows a typical application where the voltage divider is by it’s self (fully on). I’m assuming the opa333 controls voltage the resistor divider is reading to control voltage feedback and modes from the pic.
Just a guess :question:

This could work but with how the remaining divider (R1, R2) is set up, it is only voltage regulated and it will put out ~6V and kill a 3V LED.
You’d have to set up the ILIM pin of the TPS61088 correctly.
With the stock 10k for R4, it means practically no current limit. This needs to be changed!

The H1-A driver changes mode only if less than 2 seconds have passed since last power cycle or so. Under normal operating conditions this means you can leave it at whatever mode, turn it off and on and it will remain the same.

As a tinkerer I can understand Funner's viewpoint but, is it worth such effort?

Bear also in mind that if you leave the driver with just one “high” mode, I advice you to select a current output your flashlight can handle without cooking the emitter or overheating above what you may consider permissible, even in tailstanding condition if applicable.

Cheers

The H1-A driver mods you all speak of is way above my modding level.

I didn’t know if there was a simple bridge or bridge/jump with a wire for this.

Thanks for the Knowledge fellers.

Happy Day All