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

For the caps, you can order them on Mouser:

It’s not the ones recommended on the right, but they will work with 6V emitters.
If you can wait, perhaps we can bulk order together so we get a 20% lower price, as I’m planning to make some buys too.

If you want something that will work well for medium power operation(not exceeding 30W), and willing to wait a bit, here’s one similar:

I’ve checked the datasheet, and except for the capacitance, everything checks out.

The 10v version I can find but the 25v is what I have been using and is what seems to be drying up.
I think I saw a 33uf 16v version on my search somewhere and maybe what I end up going with.
I’m going to try a xhp35.2 someday with this driver so I’ll need 16v or higher with it. Seems kind of counter productive though making less lumens but I guess more throw.

Did you see the 2nd link? It seems to have the same characteristics, except for higher capacitance.

Got any idea what they charge for shipping?


Since it’s the Chinese New Year, it will ship via the USPS for 3,25$US.

However, for me, since it’s currently CNY, for Canada, it’s currently 19$US.

So yeah, I’ll have to wait a bit until I order the driver :slight_smile:

Oversea’s, yeah I did find some very reasonable priced on aliexpress, very cheap compared to in the US.
What you think?

@mod007, as long as the specs match, they should be good.

Also, how much did you pay for shipping of the Coilcraft XAL707?

It’s so freaking expensive to ship. 25$US for a single coil…

Luckily though, Mouser has a slightly lower rated saturation current inductor, which should work without prices exploding.

Mine was $8 bucks, just checked my order. I did order 2 coils that were for the V11R mod in that order also.
This is the one I ordered and used from coilcraft.

I also ordered these from mouser but haven’t used these yet.

I compared all the specs at mouser and I don’t find one difference besides ones 222MEB and the other is 222MEC.

China specs are usually not up to spec :wink: . I ordered from 2 different places on ali, I’ll let you know how these are if you haven’t ordered anything when they get here. I payed extra for e-packet so it shouldn’t be to long. Still was half what I paid for my last order with tti for 16 capacitors.

moderator007, actually the 1206 capacitor run out for me. So I use this instead and so far my Gxb172 is working very well, so I think it is good subsitute.

I use 1206 33uF 16VDC X5R for input and output capacitor: C3216X5R1C336M160AB

Because coilcraft inductor so tall, you can stack them also for more capacitance. For input, because voltage lower, you can use 10V capacitor also. I found 10V 1206 X5R 68uF: C3216X5R1A686M160AC

This two are for sale on Mouser.com. For high quality capacitor I will not trust Aliexpress caps because they may be fake ones (very common for high quality part like good capacitor and mosfet etc).

I figured I will probably end up using the 16v. I don’t want to buy any 10v because I may end building a few to run a 12v xhp35.2.
Stacking could smooth out the ripple even more if it’s needed. Thanks for the idea :+1: . That’s exactly what I did in the V11R mod.
I hope from the 2 ali stores that at least one of them will be a decent capacitor. I payed with paypal so I can always dispute “not as advertised” to a paypal claim.
I’m give it a shot anyway.

I don’t like to wait weeks for components, so I try to order all my parts in the US. But the price and unavailability has me looking for a cheaper source.

Edited: I did a little more digging and came up with a better alternative in the US that is in stock. Buy 10 or more to reduce the price.

The caps I linked above are gone like “hocus pocus” gone. They had 2 or 3 thousand 2 days ago. :open_mouth:

At moment there are some caps still in stock on digikey:

47UF 16V X5R 28,685 in stock - https://www.digikey.com/product-detail/en/tdk-corporation/C3216X5R1C476M160AB/445-6003-1-ND/2444044

47UF 25V JB 8,000 in stock - https://www.digikey.com/product-detail/en/tdk-corporation/C3216JB1E476M160AC/445-11717-1-ND/3953383

I think if run out of stock, we can use smaller capacitor but stacking to work, like 33UF.

The loneoceans designed pogoprog boards arrived yesterday. Soldered on the pogo pins and the header pins. I’am only using the board to make the connection between the usbasp and the 6 programming pads easier. There’s no need to populate the board, all the pin connections run straight to the header connections.
I use a usbasp and avrdude just like all the other firmware’s.
This is the command line I use with the fuse settings to flash.

avrdude -p attiny841 -c usbasp -u -Uflash:w:gxb172.hex:a -Ulfuse:w:0xc2:m -Uhfuse:w:0xdf:m -Uefuse:w:0xff:m

Edit the “gxb172.hex” in this command above to what ever name you have given your hex file.

The pogoprog makes flashing very convenient, It can be reflashed by just simply screwing the head off the light and lining up the pogoprog pins to the gxb172 pads and flash. No need to disassemble anything, Nice :+1: .
Here’s my set up.

Good info moderator007. :beer:

Thanks MRsDNF :+1: .
It’s been a long road, making and learning all this stuff. I had fun though :stuck_out_tongue:
The best part is, “I have seen the magic, but not the magic smoke”.

Ah that is good, yes I also use pogoprog but I notice you using thicker pcb? Loneoceans recommended use 0.8mm thick pcb, so you don't need to bend the pogo-pin. I notice when use pogo-pin to flash 841 when it is in brass pill, it is easy to short VCC and GND, so I recommend a small tape on side of pogopin which may touch the retaining ring.

I solder up pogoprog so it can supply 3.3V to VCC, using power from USB. I notice it come with small poly-fuse in case there is some short circuit on board, good addition! So may need to be careful if you only use VCC from USBISP.

Wish I had saw that a week ago. I never even noticed he recommended .8mm pcb. Thanks for the letting me know. I will order a couple .8mm in a day or two.
I was wondering why I had to bend the pins to get it to work. :person_facepalming:
The usbasp doesn’t seemed bothered by touching the vcc to ground, It just turns off and restarts. I can take a small screwdriver, short the pins, it just turns off, then restarts when I remove the screwdriver.

Good actually I notice your USBASP also has polyfuse soldered on, so this is why it also offer some short tolerance!