[[ GXB20 Driver – Homemade Constant Current Programmable XHP50 Single-Cell Boost Driver! ]]

204 posts / 0 new
Last post
loneoceans
loneoceans's picture
Offline
Last seen: 5 months 1 week ago
Joined: 01/08/2017 - 00:18
Posts: 283

Texas_Ace wrote:
Ok, so you are saying that 3A is too much for the host, not for the 219C LED's themselves. That makes more sense.

Besides heat from the LEDs, running at 3A at 9V output is also impractical from a single 18650 cell drive in most flashlights as well. The 27W output will require at least 30W input or more, which for most 18650 cells will require about >=10A input current which will be just about too much for the driver to handle safely. Contact and switch resistance will also lead to significant losses. However, 9V at 2A or so is completely OK (at least for the GXB20) Smile

www.loneoceans.com/labs/

- Next-gen Switching Drivers: Lume X1 and Lume1
- High Power Boost Drivers: GXB100 GAN 100W, GXB172 17mm 50W
- Older: GXF22, GFS16, GXB17 & GXB20

Evgeniy
Offline
Last seen: 6 days 12 hours ago
Joined: 02/01/2016 - 12:59
Posts: 106
Location: Ukraine, Odesa

loneoceans, when you plan to produce 17mm drivers ?

Flashlights : custom (Jaxman E2L with led4power LD-4 drivers and 3xOsram CQAR.CC), custom Skillhunt H03 with Osram 3К/4К, Zebralight {H600fc IV, Sc600fc IV, H600fc III}, Jaxman E2(N219b), Convoy UV.
Previous: Zebralight {H501, H600W, H600W II, H602W}, NiteCore TIPCRI, A A01, Fenix L2D CE/CEQ5.

Texas_Ace
Texas_Ace's picture
Offline
Last seen: 2 days 7 hours ago
Joined: 03/24/2016 - 07:44
Posts: 9353
Location: Everything is brighter in Texas
loneoceans wrote:

Texas_Ace wrote:
Ok, so you are saying that 3A is too much for the host, not for the 219C LED’s themselves. That makes more sense.

Besides heat from the LEDs, running at 3A at 9V output is also impractical from a single 18650 cell drive in most flashlights as well. The 27W output will require at least 30W input or more, which for most 18650 cells will require about >=10A input current which will be just about too much for the driver to handle safely. Contact and switch resistance will also lead to significant losses. However, 9V at 2A or so is completely OK (at least for the GXB20) Smile

I didn’t see this in the OP. Curious what are the limits of this driver when it comes to power. I assume that the true limits lie in the input current?

I assume this could boost power to an 12v XHP35 as well with some component changes, what kind of output current would be possible?

Also, did you ever say what components you are using for this driver? I never saw a parts list, curious what boost IC you are using along with the rest of the parts.

If this could be shrunk to 17mm an xhp35 S2+ could be a really interesting EDC light (or xhp50.2 for that matter).

Schoki
Schoki's picture
Offline
Last seen: 3 weeks 5 hours ago
Joined: 03/27/2017 - 15:34
Posts: 223
Location: Germany

A TPS61088 is used as the boost converter, here is the website, even with a schematic: loneoceans labs | GXB20 v1 LED Driver PCB
I currently try to get it shrunk to 17mm (with a few modifications to the circuit).

loneoceans
loneoceans's picture
Offline
Last seen: 5 months 1 week ago
Joined: 01/08/2017 - 00:18
Posts: 283

Evgeniy wrote:
loneoceans, when you plan to produce 17mm drivers ?

Very soon! Layout for GXB17 is basically done. Just need to order a few PCBs and to fine tune everything (render above is not final yet, was taken during initial design). The hardest part is designing within the 6/6mil constraints of OSHpark and using 2 layers with no air-wires, though I've fabricated 5/5mil with them and they seem.. just fine. I suspect even 4/4mill will still be OK! 

 

Texas_Ace wrote:

I didn't see this in the OP. Curious what are the limits of this driver when it comes to power. I assume that the true limits lie in the input current? I assume this could boost power to an 12v XHP35 as well with some component changes, what kind of output current would be possible? Also, did you ever say what components you are using for this driver? I never saw a parts list, curious what boost IC you are using along with the rest of the parts. If this could be shrunk to 17mm an xhp35 S2+ could be a really interesting EDC light (or xhp50.2 for that matter).

There are several aspects to the limits, but not hitting on the more nuanced ones would be the maximum input current of 10A. In addition, making the driver efficient at different output / input voltages requires fine-tuning the component choices such as the switch frequency, inductor and error compensation network - i.e. one cannot just run the driver for a different output configuration while expecting similarly high-efficiency output. However, if one is willing to sacrifice a bit of performance, then changing it should be fairly straightforward. 

I'm still in the process of writing up a page for it but my 'sales' page has a decent overview of the BOM and Schematics. http://loneoceans.com/labs/sales/gxb20v1/ Note the V2 version is fairly different with some enhancements. 

Finally there are obviously other limits to the other components such as minimum voltage input required for proper operation, thermals (getting pretty warm already at ~18W output) as well as boost inductor. Trade-offs I suppose between cost, size, efficiency, performance and features Smile 

www.loneoceans.com/labs/

- Next-gen Switching Drivers: Lume X1 and Lume1
- High Power Boost Drivers: GXB100 GAN 100W, GXB172 17mm 50W
- Older: GXF22, GFS16, GXB17 & GXB20

Texas_Ace
Texas_Ace's picture
Offline
Last seen: 2 days 7 hours ago
Joined: 03/24/2016 - 07:44
Posts: 9353
Location: Everything is brighter in Texas
Schoki wrote:
A TPS61088 is used as the boost converter, here is the website, even with a schematic: loneoceans labs | GXB20 v1 LED Driver PCB I currently try to get it shrunk to 17mm (with a few modifications to the circuit).

Thanks for the link, I didn’t see that before.

So it is setup for a 7A input, thats pretty darn good. What is the limiting factor? I see the inductor is rated at 11A but didn’t take the time to look up everything else.

With a 7A input limit, that would be around 1.75-2A to an xhp35, which is pretty darn good. If it could drive it a bit harder to 2.25 – 2.5A it would be perfect.

Schoki
Schoki's picture
Offline
Last seen: 3 weeks 5 hours ago
Joined: 03/27/2017 - 15:34
Posts: 223
Location: Germany

I think one limiting factor is power dissipation. Even if the converter maybe has ~90% efficiency at 25W of power, it still gets pretty hot.

Texas_Ace
Texas_Ace's picture
Offline
Last seen: 2 days 7 hours ago
Joined: 03/24/2016 - 07:44
Posts: 9353
Location: Everything is brighter in Texas

Yeah, heat buildup should be the limiting factor, the question is which component? If you stuck the driver with thermal cubes you can usually get some more out of it if you know where the heat is coming from.

Schoki
Schoki's picture
Offline
Last seen: 3 weeks 5 hours ago
Joined: 03/27/2017 - 15:34
Posts: 223
Location: Germany

It’s either the coil or the converter itself. It’s difficult to say because the converter works a little different and has like a “built-in diode”. The diode is replaced with a mosfet controlled by a deadtime
control logic.

It’s really annoying that I spent all the time fiddling around with the 17mm board (probably finished by tomorrow), but loneoceans did it already Facepalm .
I hope my version isn’t completely wasted time Wink

Texas_Ace
Texas_Ace's picture
Offline
Last seen: 2 days 7 hours ago
Joined: 03/24/2016 - 07:44
Posts: 9353
Location: Everything is brighter in Texas

Schoki wrote:
It’s either the coil or the converter itself. It’s difficult to say because the converter works a little different and has like a “built-in diode”. The diode is replaced with a mosfet controlled by a deadtime
control logic.

It’s really annoying that I spent all the time fiddling around with the 17mm board (probably finished by tomorrow), but loneoceans did it already Facepalm .
I hope my version isn’t completely wasted time Wink

Very interesting, that is a nice IC. I was curious why I didn’t see a diode listed in the parts list.

Agro
Agro's picture
Offline
Last seen: 3 weeks 5 days ago
Joined: 05/14/2017 - 11:16
Posts: 6801
Location: Ślōnsk
Texas_Ace wrote:
loneoceans wrote:

Texas_Ace wrote:
Ok, so you are saying that 3A is too much for the host, not for the 219C LED’s themselves. That makes more sense.

Besides heat from the LEDs, running at 3A at 9V output is also impractical from a single 18650 cell drive in most flashlights as well. The 27W output will require at least 30W input or more, which for most 18650 cells will require about >=10A input current which will be just about too much for the driver to handle safely. Contact and switch resistance will also lead to significant losses. However, 9V at 2A or so is completely OK (at least for the GXB20) Smile

I didn’t see this in the OP. Curious what are the limits of this driver when it comes to power. I assume that the true limits lie in the input current?

I assume this could boost power to an 12v XHP35 as well with some component changes, what kind of output current would be possible?

Also, did you ever say what components you are using for this driver? I never saw a parts list, curious what boost IC you are using along with the rest of the parts.

If this could be shrunk to 17mm an xhp35 S2+ could be a really interesting EDC light (or xhp50.2 for that matter).


Or triple xhp35.
Though my dream would be this driver on a 20mm DTP PCB. With a series od 3 XP-L2s on the same board.
clemence
clemence's picture
Offline
Last seen: 1 year 1 day ago
Joined: 07/12/2015 - 02:58
Posts: 2474
Location: Bali - Indonesia

I’m a driver but not a driver expert nor tweaked any LED drivers (resistor stacking doesn’t count) before. My question is: from all those components cramped in a tiny 17mm which one is the hottest one? I usually find the big square box is the hottest one, am I wrong?
Can we remotely place it somewhere else (near the tailcap perhaps) to save space and distribute the heat better?

- Clemence

loneoceans
loneoceans's picture
Offline
Last seen: 5 months 1 week ago
Joined: 01/08/2017 - 00:18
Posts: 283

clemence wrote:
I'm a driver but not a driver expert nor tweaked any LED drivers (resistor stacking doesn't count) before. My question is: from all those components cramped in a tiny 17mm which one is the hottest one? I usually find the big square box is the hottest one, am I wrong? Can we remotely place it somewhere else (near the tailcap perhaps) to save space and distribute the heat better? - Clemence

Typically with how the drivers are placed (right behind the LED in the same thermal block), the major heat producer is the LED itself! However you are right that the next main heat producer is typically the inductor. However moving it far away from the LED (e.g. at the tailcap) isn't typically a good idea, since a significant amount of parasitic inductance is added, not to mention very large DC restive losses (since the inductor current is typically very high), as well as skin-effect losses at high switching frequencies. The ideal layout is to keep the inductor as close to the power circuit as possible. 

Practically speaking, I think for most single-cell flashlights (esp. 18650), the maximum reasonable power one can expect is about 25-30W for short durations and <20W for any reasonable run-time. Anything longer than that would require a fairly large host with cooling fins, which I suppose defeats the 1-cell form factor (i.e. desirable to be small); not to mention DC power losses. For example, just 50mR DC losses from a single 4V cell outputting 30W would lead to 2.815W lost in just the wiring/switch/spring, a loss of almost 10%.

As a side note, the GXB17 is well underway - follow it here: http://budgetlightforum.com/node/54827

www.loneoceans.com/labs/

- Next-gen Switching Drivers: Lume X1 and Lume1
- High Power Boost Drivers: GXB100 GAN 100W, GXB172 17mm 50W
- Older: GXF22, GFS16, GXB17 & GXB20

Agro
Agro's picture
Offline
Last seen: 3 weeks 5 days ago
Joined: 05/14/2017 - 11:16
Posts: 6801
Location: Ślōnsk

loneoceans wrote:

 



Maximum efficiency was measured at around 98+% efficiency at lowers loads of around 750mA out.This drops gradually to 87% or so at 3A output, meaning about 2W dissipated in the driver itself! Most of the heatsinking of the driver occurs through the ground ring around the driver so mounting it in a host properly is also critical. Increased temperature after longer runs will certainly affect the efficiency though. In all the driver seemed to regulate current just fine all the way up to the maximum 3A load.  Finally, keep in mind that this efficiency number should probably be treated more as a guideline. I expect the efficiency to actually be better since there probably is non-trivial ohmic losses in connection points / spring, and a properly seated driver in a good host with a good switch should do a little better. So this efficiency is the measured system efficiency, driver efficiency should be a little higher (esp on the high currents). Finally the shape looks roughly in-line with my simulations should it at least gives me a good confidence in my measurements. Overall approaching 90% system efficiency is still pretty good for me!


Is this efficiency measured for a particular input voltage or is it an integration over some range?
loneoceans
loneoceans's picture
Offline
Last seen: 5 months 1 week ago
Joined: 01/08/2017 - 00:18
Posts: 283

Agro wrote:
loneoceans wrote:

 

Maximum efficiency was measured at around 98+% efficiency at lowers loads of around 750mA out.This drops gradually to 87% or so at 3A output, meaning about 2W dissipated in the driver itself! Most of the heatsinking of the driver occurs through the ground ring around the driver so mounting it in a host properly is also critical. Increased temperature after longer runs will certainly affect the efficiency though. In all the driver seemed to regulate current just fine all the way up to the maximum 3A load.  Finally, keep in mind that this efficiency number should probably be treated more as a guideline. I expect the efficiency to actually be better since there probably is non-trivial ohmic losses in connection points / spring, and a properly seated driver in a good host with a good switch should do a little better. So this efficiency is the measured system efficiency, driver efficiency should be a little higher (esp on the high currents). Finally the shape looks roughly in-line with my simulations should it at least gives me a good confidence in my measurements. Overall approaching 90% system efficiency is still pretty good for me!

Is this efficiency measured for a particular input voltage or is it an integration over some range?

 

Hello; as mentioned earlier in the post, 

"The test [of which the results were plotted above] was conducted as follows. The driver was hooked up to a constant voltage programmable Agilent power supply. In this case I conducted the test at 3.7V in across the range (driver was also tested at a variety of input voltage from 4.5V to <3V but less comprehensively). Input current and voltage was measured via Kelvin terminals to avoid errors due to lead resistances. Output current was measured across the load resistor as well as the output to find total driver efficiency. A total of 20 constant current levels were tested and measurements taken. "

I understand the efficiency may vary across different input voltages but a quick test from around 4.2 to 3.5V for a few different output levels seemed to yield comparable efficiency.

www.loneoceans.com/labs/

- Next-gen Switching Drivers: Lume X1 and Lume1
- High Power Boost Drivers: GXB100 GAN 100W, GXB172 17mm 50W
- Older: GXF22, GFS16, GXB17 & GXB20

Agro
Agro's picture
Offline
Last seen: 3 weeks 5 days ago
Joined: 05/14/2017 - 11:16
Posts: 6801
Location: Ślōnsk

Thanks for the explanation

Barkuti
Barkuti's picture
Offline
Last seen: 1 hour 49 min ago
Joined: 02/19/2014 - 14:46
Posts: 5532
Location: Alhama de Murcia, Spain

3.5 to 4.2V is nowhere near the real voltage window of a fully loaded li-ion cell for all of its discharge curve, and that's not to say the driver sees less voltage due to contact losses. As an advocate of worst case scenario conditions, for me the input voltage value which really matters is the one which makes the driver's life harder, so I'd also test with the possible voltages coming from a nearly depleted fully loaded li-ion cell in an overdriven driver: 2.7 - 2.8V.

Great work by the way.

 

Deleting a just published post causes the forum thread answer notification to fail. Thus, if you need to change your just published post, edit it. Thanks.

Please avoid fully quoting lenghty posts, namely with nested quotes. Trim quotes down to the essential. Helps with neatness and legibility. Thanks.

I recommend saying no to Covid vaccine. Listen to your soul. Innocent

loneoceans
loneoceans's picture
Offline
Last seen: 5 months 1 week ago
Joined: 01/08/2017 - 00:18
Posts: 283

Barkuti wrote:

3.5 to 4.2V is nowhere near the real voltage window of a fully loaded li-ion cell for all of its discharge curve, and that's not to say the driver sees less voltage due to contact losses. As an advocate of worst case scenario conditions, for me the input voltage value which really matters is the one which makes the driver's life harder, so I'd also test with the possible voltages coming from a nearly depleted fully loaded li-ion cell in an overdriven driver: 2.7 - 2.8V.

Great work by the way.

 

 

It depend significantly on what cell is being used, how fresh the batteries are, and at what sort of operating limits one will tolerate the driver at. I designed the driver without really expecting to push LEDs to their absolute limits - this places not only significant thermal stress to the LEDs, but also the batteries etc and affects long term reliable operation. You are right to say that the driver input voltage will be closer to 3V- on a depleted overdriven cell - at this point the driver will try to draw even more current from the battery causing the voltage to drop even further, until low-voltage protection kicks in. That said, I'm currently limited in my bench power supplies to provide sufficient current at such low voltages, so it's also a limit to my test gear for proper characterization Smile

As a side now, I'll be focusing my efforts on the GXB17 development, so expect to see less updates over here (since the GXB20 V2 is essentially complete and is working happily in 2 of my flashlights!), and I'll be focusing on the GXB17 over here: http://budgetlightforum.com/node/54827

www.loneoceans.com/labs/

- Next-gen Switching Drivers: Lume X1 and Lume1
- High Power Boost Drivers: GXB100 GAN 100W, GXB172 17mm 50W
- Older: GXF22, GFS16, GXB17 & GXB20

clemence
clemence's picture
Offline
Last seen: 1 year 1 day ago
Joined: 07/12/2015 - 02:58
Posts: 2474
Location: Bali - Indonesia

I see the trend in FL manufacturers is keep pushing the limit until the efficiency is just a bit better than xenon bulb torches years ago.
Higher voltage LED and lower current applications is now becoming more mainstream to boost overall efficiency. Boost drivers have to keep up sooner or later.

Great job Loneoceans.

purduephotog
Offline
Last seen: 6 months 3 weeks ago
Joined: 01/22/2015 - 14:40
Posts: 30

I’m greedy! I have some nice 4x UV 20mm boards and needed a17mm driver.

https://m.fasttech.com/products/1616/10002799/1208600-driver-pillar-w-em...

http://www.ebay.com/itm/311785443407

If you need cash for dabbing… Will donate/Kickstart.

Agro
Agro's picture
Offline
Last seen: 3 weeks 5 days ago
Joined: 05/14/2017 - 11:16
Posts: 6801
Location: Ślōnsk

purduephotog wrote:

If you need cash for dabbing… Will donate/Kickstart.


+1
loneoceans
loneoceans's picture
Offline
Last seen: 5 months 1 week ago
Joined: 01/08/2017 - 00:18
Posts: 283

Hello all, just a quick update that I've a simple write-up (in progress) of this LED driver. 

http://loneoceans.com/labs/gxb20/

It's mostly a rehash of stuff on this thread though. More details to be added there as I go along. Thanks for reading!

www.loneoceans.com/labs/

- Next-gen Switching Drivers: Lume X1 and Lume1
- High Power Boost Drivers: GXB100 GAN 100W, GXB172 17mm 50W
- Older: GXF22, GFS16, GXB17 & GXB20

Texas_Ace
Texas_Ace's picture
Offline
Last seen: 2 days 7 hours ago
Joined: 03/24/2016 - 07:44
Posts: 9353
Location: Everything is brighter in Texas

Great writeup, very informative.

Agro
Agro's picture
Offline
Last seen: 3 weeks 5 days ago
Joined: 05/14/2017 - 11:16
Posts: 6801
Location: Ślōnsk

Yes, very good, thanks!
Do you intend to extend the writeup to cover GXB17 too?
You mention that you use PWM because the driver won’t be used under 200 mA. That’s not true already. Is it still PWM?
In the writeup you mention having the lowest mode at 50 mA. I notice 1 mA in this thread. Which is the latest value? Also, it would be useful to add the range of currents supported by GXB20 v2, not just that there are 256 of them.

Agro
Agro's picture
Offline
Last seen: 3 weeks 5 days ago
Joined: 05/14/2017 - 11:16
Posts: 6801
Location: Ślōnsk

BTW, loneoceans, have you considered something like ATBTLC1000 for BT programming?

loneoceans
loneoceans's picture
Offline
Last seen: 5 months 1 week ago
Joined: 01/08/2017 - 00:18
Posts: 283

Agro wrote:
Yes, very good, thanks! Do you intend to extend the writeup to cover GXB17 too? You mention that you use PWM because the driver won't be used under 200 mA. That's not true already. Is it still PWM? In the writeup you mention having the lowest mode at 50 mA. I notice 1 mA in this thread. Which is the latest value? Also, it would be useful to add the range of currents supported by GXB20 v2, not just that there are 256 of them.

Yes the GXB17 driver will have its own writeup. Yes the driver is running in FPWM mode, but you're confusing that with the 'regular PWM' running in the kHz range which people use to modulate brightness. The Forced PWM mode is how the boost driver is configured and how it regulates its output. In this case that PWM is running in hundreds of kHz and is the switching frequency of the boost switches. The output driving the LED is true constant current.  Finally if you look at the firmware diagram at the bottom of the page, the driver has a 'moonlight' mode which drives the LED at a very low current of around 1mA. The range of currents supported are 256 constant-spacing values, but the max is determined by its desired mode of operation, e.g. running at 6V out or 9V out, and configured accordingly to your desired maximum current.

 

Agro wrote:
BTW, loneoceans, have you considered something like ATBTLC1000 for BT programming?

I've worked on similar parts in the past but it really seems like far too complex work for a driver like this and a bit too much overhead as well as cost. 

www.loneoceans.com/labs/

- Next-gen Switching Drivers: Lume X1 and Lume1
- High Power Boost Drivers: GXB100 GAN 100W, GXB172 17mm 50W
- Older: GXF22, GFS16, GXB17 & GXB20

Agro
Agro's picture
Offline
Last seen: 3 weeks 5 days ago
Joined: 05/14/2017 - 11:16
Posts: 6801
Location: Ślōnsk

As far as I understand: You’re PWMing power into an inductor and you could be PFMing which is more efficient at low load. I have no idea what ‘low’ is, but seeing you mention 200 mA I assumed that this number is somehow related to the limit of lowness. Since GXB20v2 bottom 200 times lower than that, I assumed PFM could be preferable at the lowest modes.

I’m not sure if it’s suitable, but ATBTLC1000 starts at $1.71 at DigiKey. I believe that many would pay even several dollars to be able to easily have perfect modes.

Moodular and Lux-RC offer such lights already, though that’s well within the high end of the market.

loneoceans
loneoceans's picture
Offline
Last seen: 5 months 1 week ago
Joined: 01/08/2017 - 00:18
Posts: 283

Agro wrote:
As far as I understand: You're PWMing power into an inductor and you could be PFMing which is more efficient at low load. I have no idea what 'low' is, but seeing you mention 200 mA I assumed that this number is somehow related to the limit of lowness. Since GXB20v2 bottom 200 times lower than that, I assumed PFM could be preferable at the lowest modes. I'm not sure if it's suitable, but ATBTLC1000 starts at $1.71 at DigiKey. I believe that many would pay even several dollars to be able to easily have perfect modes. Moodular and Lux-RC offer such lights already, though that's well within the high end of the market.

The SOC is cheap but there are a lot of peripheral components that need to go alongside almost all RF SOCs including a chip antenna, internal regulator inductors and passives and crystals etc. That's not even including the very limited PCB space on a 20mm/17mm diameter board. Could I make it work? Sure, but this will require much more expensive PCB fab requirements, will complicate hand-assembly, and still requires more firmware overhead... Lux-RC's optical flashing programming does look interesting though but again requires additional infrastructure on both the host and client side, which is far too much work for this particular hobby project (which I only planned to make a few for my own flashlights). However anyone is more than welcomed to add more features on to the GXB driver. smile

Changing FPWM to PFM is just a disconnection of the mode pin so it's really not a big deal. It's a trade-off between audible PFM at low loads with higher efficiency, or just sticking with FPWM for always quiet operation. 

www.loneoceans.com/labs/

- Next-gen Switching Drivers: Lume X1 and Lume1
- High Power Boost Drivers: GXB100 GAN 100W, GXB172 17mm 50W
- Older: GXF22, GFS16, GXB17 & GXB20

Agro
Agro's picture
Offline
Last seen: 3 weeks 5 days ago
Joined: 05/14/2017 - 11:16
Posts: 6801
Location: Ślōnsk

loneoceans wrote:

Agro wrote:
As far as I understand: You’re PWMing power into an inductor and you could be PFMing which is more efficient at low load. I have no idea what ‘low’ is, but seeing you mention 200 mA I assumed that this number is somehow related to the limit of lowness. Since GXB20v2 bottom 200 times lower than that, I assumed PFM could be preferable at the lowest modes. I’m not sure if it’s suitable, but ATBTLC1000 starts at $1.71 at DigiKey. I believe that many would pay even several dollars to be able to easily have perfect modes. Moodular and Lux-RC offer such lights already, though that’s well within the high end of the market.

The SOC is cheap but there are a lot of peripheral components that need to go alongside almost all RF SOCs including a chip antenna, internal regulator inductors and passives and crystals etc. That’s not even including the very limited PCB space on a 20mm/17mm diameter board. Could I make it work? Sure, but this will require much more expensive PCB fab requirements, will complicate hand-assembly, and still requires more firmware overhead…

Lux-RC’s optical flashing programming does look interesting though but again requires additional infrastructure on both the host and client side, which is far too much work for this particular hobby project (which I only planned to make a few for my own flashlights). However anyone is more than welcomed to add more features on to the GXB driver. smile


Flashing? I thought they used BT! Cool idea….does the phone flash back?

loneoceans wrote:

Changing FPWM to PFM is just a disconnection of the mode pin so it’s really not a big deal. It’s a trade-off between audible PFM at low loads with higher efficiency, or just sticking with FPWM for always quiet operation. 


Is it possible to do programatically?

BTW, I don’t see a link to the firmware sources…

loneoceans
loneoceans's picture
Offline
Last seen: 5 months 1 week ago
Joined: 01/08/2017 - 00:18
Posts: 283

Agro wrote:
Flashing? I thought they used BT! Cool idea....does the phone flash back?

It's a nice idea, I might have to think about it for a future product since it just requires a small photosensor. The only requirement is the additional cost of developing an app (e.g. web-app), define a protocol, and implement it so the light can be programmed using flashing screen of a phone or a computer screen.

 

Agro wrote:
Is it possible to do programatically?

No unfortunately not. PFM or FPWM mode is programmed by connecting or floating the mode pin of the boost converter driver IC.

www.loneoceans.com/labs/

- Next-gen Switching Drivers: Lume X1 and Lume1
- High Power Boost Drivers: GXB100 GAN 100W, GXB172 17mm 50W
- Older: GXF22, GFS16, GXB17 & GXB20

Pages