Very nice!
@ICSK, developing a driver is one thing, but offering them for sale is a very different game. I look at Lexel in full admiration that he is able to maintain a custom driver sales operation, and at not much more than component costs, it takes a lot of time and dedication, not many are able to do that.
Totes Mazeballs work.
Would be very interested if these can somehow end up for sale… Cross fingers…
Even if loneoceans etc cant make enough of them to meet demand, if someone else can (mntelectronics maybe), and give them credit (and maybe a cut of the sales) etc…
TA, I've used no smaller than 0402 for all the passives. The big caps are 1206. They're small, but still hand solderable. The other components are more difficult to solder but it's ok if I'm just making a few. Eventually when I get the driver nailed down I'll just send them off for PCBA ^_^. Mike, as you can tell the driver is still very much in development but like with my previous drivers (see my signature), all of it will be released so everyone can build their own 
I'm not quite sure yet; that's the main reason why I build the driver into a test flashlight so I can verify and fine tune the features, such as thermal PID management. Right now I have it designed so once the temperature sensor hits 60C (adjustable), it adjusts the output current in such a way that it maintains the 60C temperature setting and adjusts accordingly. So for example if you dunk it in a bowl of cold water, the brightness will ramp back up again. So the light will remain at full output until the set temperature is hit, and this can depend on how well sinked the LED is to the MCPCB and the pill, the driver board to the pill, the starting temperature of the light etc.
As described, the original point of the project wasn't to develop a driver for sale, and I'm certainly not planning to make any money out of this at all.
It's one thing to offer a single-sided driver board with fairly large components for sale - that's pretty easy since I can do a single pass solder paste application, hand place the components and reflow it all at once. However it's really not time or cost effective to do this for a dense double-sided board with small components like the GXB172, and I certainly wouldn't want to offer such a product for sale where I can't ensure every build would be up to my quality standard, within a reasonable cost or time.
However if there is sufficient interest, I think here's what I can do. I'd like to fine tune the driver electricals and make sure that it's reasonably robust, work on getting at least a decent firmware going (still a bit more work to do), and optimize the BOM for production and cost. I'm not keen of the idea offering something for sale if it's not robust, but don't worry all of this will be open source regardless
Then if people like what's on offer, I can just send for an entire batch to be fabricated and assembled say in the ~100 to 1000 quantity with some sort of decent built-in firmware. I suspect once we hit the 1000 order threshold, the driver cost will be pretty affordable! 100s quantities should be decent but will still be fairly expensive I guess, but certainly doable. It'll come with some stock firmware but those interested can then do their own firmware mods.
I hope in the future more talented people than me can improve on the firmware for it and future revisions too! ^_^
But right now, I'd like to focus on making the driver actually a decent driver first, before thinking about production! It's easy to get the driver working (it's working now!), but it's a bit more work to make sure all the edge cases are covered!
When you get all the bugs worked out and tested for stability, Im sure your going to have a lot of interest with this driver. People all over the community have been calling for this driver for a long time. It might help to see how much interest there is with this driver by starting a “Who’s interested thread”. That should give you a idea of the number of drivers you’ll need to produce.
We all appreciate you taking the time to develop this and finally bring this to market. :+1:
There are 2 concurrent developments of very similar drivers.
One is close to enter the market, produced by Lexel.
The other is here, not ready either, with noone to produce it for sale yet.
The option of lowering costs by increasing scale is nice, certainly worth considering. Especially that this driver is simply far from cheap. But leaves some questions:
Hi Loneoceans,
This is a very good driver, I like it. Is it possible to get the PWM dimming version? It would be extremely useful if it has both PWM and current dimming options.
- Clemence
There has been massive interest in this since the first GXB20 thread: [[ GXB20 Driver – Homemade Constant Current Programmable XHP50 Single-Cell Boost Driver! ]]. Then came the first GXB17 thread: GXB17 Driver – 17mm 6V 3A / 12V 1.5A Constant Current Programmable Single-Cell Boost Driver which generated interest also. But despite all this interest not a single driver was made from anyone here besides loneoceans, at least to my knowledge. Now here is a new GXB17 with the same teasers as the first…
The good thing that came from those first two GXB threads is that it inspired others like Schoki and Jensen567 to start designing one. So no matter what happens to this new GXB driver, a 17mm boost driver is on the way, designed for usage with already known BLF firmware (which thankfully has nothing to do with arduino).
Why? What is the benefit of the PWM?
Many leds have large tint changes at different currents, if you want a light that has a consistent tint, it must run on one fixed current. The way to create different brightness modes using one fixed current is using PWM.
When you use constant current dimming, the LED tint changes with the current. PWM dimming has nearly no tint shift at all.
Consistent CCT, tint, and CRI across the whole current range. Once you set the starting highest current, all lower modes will have same CCT, tint, and CRI. Current controlled lighting will give you CCT/tint/CRI shifts.
Not for flashlight uses due to obvious inefficiency though, this PWM dimming is desired in general/specialty lighting.
- Clemence
Everyone I would hold your horses. The driver needs to be fully tested first, he is still testing some things I think.
Once the driver is tested and verified working under various conditions then it would be time to start talking about having them made.
Put simply, where there is a demand, there is a way to fulfill that demand. I also have a few possible options floating around when it is closer to being production ready.
I guess I kind of worded that wrong. I know the interest is there, it has been for a long time.
Maybe like a pre-order thread. “If I produce this driver who would be interested and how many” thread.
Loneoceans was saying once his order hit 1000 that the price would probably decrease per board.
I’m thinking 1000 would probably be gone pretty quick and its possible that 1000 could be sold on a pre-order.
Depends on a few variables with the specs of the driver or if another enters the market at the same time.
I myself would buy 5 to 10 boards depending on specs and price. 200 flashaholics buying 5 boards each equals 1000 boards.
moderator007
You can check demand in Lexel’s thread. 1000pcs groupbuy will take years. Custom driver cant be more popular than Q8, for example (how much time it take to reach 1000pcs for Q8?).
Anyone have experience with ordering cnc-mount pcbs? MOQ can be even more than 1000pcs.
There are a few other options that could possibly see them produced as well depending on how things go. Once loneocens is happy with the design and gives a “final release” we can discuss getting them made. From experience it is best to wait until the driver is done before talking about this type of thing though.
I went back and read through this thread. Looked on loneoceans site. Read the dataSheet for the ic. Well looks like the driver can only be used with a led at or above 6 volts vf or series leds. I had thought this would run a single led (such as a xpl) at a constant current through the entire run time until a single cell was depleted.I know see that the led must have a vf of 6v or more to work. So while there is interest still there for this driver, it is limited from its output voltage.
Loneoceans have you tried to see how low the output voltage can actually go.
A boost driver can only increase voltage above that of the input voltage. So if you input 4V, then then lowest it can possibly go is 4V.
A buck driver would be needed for an XP-L, although it would fall out of regulation fairly quickly with only one cell.
So what is actually needed is a more advanced buck/boost driver. These are hard to come by and would be very challenging to fit on a driver this size.
A 30q cell can only do 4v for seconds at 5 amp load. At 4v a xpl v6 would see 5 amps, nothing crazy. So if a boost driver was set at 5 amps output it would run direct drive for maybe a few minute and hit the vf of the xpl at 5 amps and then switch to boost through almost the entire discharge, at least theoretically speaking.A xpl v6 needs 3.8v to run at 5 amps according to djozz’s graph. Cree XP-L V6 2C led, tested against XM-L2 T6 3C, edit23/7: I repeated the test and measured a dedomed XP-L
Fet and amc7135 drivers would fall out of regulation about 1/3 the way through at this current and reduce current as the battery voltage decreases. Probably to much for a xpl2, but a xpl or xml should be fine.
A 30q cell can only do 4v for seconds at 5 amp load. At 4v a xpl v6 would see 5 amps, nothing crazy. So if a boost driver was set at 5 amps output it would run direct drive for maybe a few minute and hit the vf of the xpl at 5 amps and then switch to boost through almost the entire discharge, at least theoretically speaking.A xpl v6 needs 3.8v to run at 5 amps according to djozz’s graph. Cree XP-L V6 2C led, tested against XM-L2 T6 3C, edit23/7: I repeated the test and measured a dedomed XP-L
Fet and amc7135 drivers would fall out of regulation about 1/3 the way through at this current and reduce current as the battery voltage decreases. Probably to much for a xpl2, but a xpl or xml should be fine.
But I’m with yeah, a buck boost driver would work best and fit more applications.
I believe Lexels upcoming Boost driver will handle the larger sizes. I think his will be 20mm and up IIRC.
What really makes the GXB172 unique is its small size.
I remember reading somewhere that Lexel had Bistro HD OTSM (or some version of Bistro) that could work on both switch types.
Hopefully Lexel can confirm both my statements.