[ GXB172 - 50W Single Cell 17mm Boost Driver! ]

Absolutely incredible!!!

Its kind of ironic he made the flashing key but didnt release the source code for the firmware

Does anyone know the replacement parts required for 12V operation from 1S? I see loneoceans tested but I can’t find any info which components to replace and what values to replace them with.

I like to know too but I dont yet use 12V led. Maybe you can ask him by email? loneoceans seem to be busy from blf recently, but he reply my email when I was building gxb172. Are you making your own gxb172 also?

Ok, I’ll just email him later on. I’m not building one yet so no hurry.

I’d be in for 1 of these. Wish I had the expertise and time to do that. Impressive. Not to many boost drivers out there.

Very impressive. I’m in for 2 if they could be sold.

12v operation has been updated in Loneoceans BOM REV.A2.
It should perform very similar to the H2-C driver.
Jensen567 has a nice thread already setup with his test data. Buck and Boost Drivers, Testing, Modding, and Discussion (Pic Heavy)

RevA2 says it was updated January 2019.

There is also a matching board update dated Feb 3, 2019. OSH Park ~

“GXB172 - 17mm Boost LED Driver - Rev A2 - Adjusted silkscreen, soldermask expansion - Adjusted components for better clearance - Added bypass R15 (~560R works fine) if required - Optional: R15, C12, R3, C15 Otherwise identical to GXB172 Rev A.”

Looks like Gao has found some time to put some finishing touches on this driver.

There are parts on the BOM that refer to E-switches. Is E-switch support new?

If anyone does make these for the community I would like one please

That was what I was thinking too. Maybe his working on implementing the e-switch. Good to see him back on this project.
I made the changes on the driver for 12v operation with a XHP35.2 and got 3 amps at the led but I haven’t tested how well it might handle this.
It might not make that current with the voltage sag from a li-ion, I was using a power supply. It will be voltage dependent in a flashlight.

Here is someone offering to build a few: Any intrest in loneoceans's 50w boost 17mm driver?

Eswitch should be easy to implement in code, hes using an ATiny and has pins that are unused which can drive indicator leds or an eswitch. This can easily be implemented in code quick and dirty without any changes to the design however Ideally, design should be edited to include pull up and pull down resistors for switch support. I don’t plan on doing this for my first run however I can mess with the code and add eswitch support, just solder your switch to v+ and a pin on the controller (micro will blow if above whatever the spec sheet says).

Internal pull up in ATtiny is good enough. I’ve never had issues with that. Hardware supports E-switch as parts are listed in BOM. Don’t know about firmware though.

When looking at BOM, it look like loneoceans already have on board resistor and cap for switch debounce in hardware already! But from his webpage it look like eswitch can be support but no firmware written for it yet.

It might be possible to do an e-switch right now by momentarily opening the power to the +vcc pin and making the attiny reboot. Maybe this is what he is doing and the resistor and capacitor he’s added just debounce the switch.

As far as I know the code has not been released. Only the hex has been published and there is no way to modify it.

The good news is that he appears to be back working on this driver. His intention all along was to release the code when he was happy with it.

It’s probably best to sit tight for a couple weeks and give him time to finish what he is working on.

Thanks for the heads up, I saw that post after I put up mine and responded there too :smiley:

I just finished shoving the GXB172 modified for 12v operation in a Convoy S2+ with a XHP35.2 4000k from Arrow.
I got 2600 lumens on start up and drawing 17 amps or so my meter says. I like the beam much better than the xhp50.2 in the convoy.
Has a nice brightly defined hotspot. Much more throw for sure. Shinning both lights together it looks like the xhp35.2 just drowns the 50 out. But I know its only because the hotspot is so much more intense. I like it. :wink:

How accurate do you think your 2600 lumen is? From what I’ve heard people say about the 35.2, it should not be much or any brighter than the older 35. The older 35, even with a very powerful driver, would not get to 2600 lumen OTF. This driver is not super powerful, like 3A+, it says it should be 2.5A. So overall I would not expect 2600 lumen, but maybe the 35.2 has a real improvement in output?

The HD bins go higher than HI so its possible i’d bet