- One String - a novel bitfury miner design -

[intron]

We did a 15 bitfury miner design using the proprietary
'string' feature this ASIC has. In a string, all chips are
arranged in a series configuration and power is applied
accordingly. So instead of a low voltage/high current
power supply, a less exotic power source can be used,
driving down cost considerably and taking up less board
area.

The board measures 70 x 100 mm, is powered with 12 Volt
and has a USB interface. As no DC/DC converter is needed,
BOM costs can be well below $ 10 (ex. PCB and cooling).

Hashrate can be compared to conventional designs and
overclocking can be achieved by just increasing the supply
voltage within certain limits. Reported hashrate is with 12V8
power supply and with a 2A6 current.

Cooling for the prototype was done using a low-cost
CPU heatsink. Temperatures measured on the PCB were
in the 50..70 oC range.







intron & c-scape

Note: Some images were retouched to protect our IP.
Hope you understand.

[intron]

- reserved -

[deathmul]

How much?

[fractal02]

Well done Intron and c-scape !

Selling a miner based on this design is planned ?

[intron]

How much?

We don't sell miners, we only design miners.

The design can be purchased so other parties can
produce them. We have not set definitive prices
or conditions yet, just probing interrest for now.

intron

[Foofighter]

looks nice guys! But if the BF chip situation stays the same..

[rammy2k2]

with hashfast announcing 500 GH / chip .. this is ... dust in the wind ... all respect for your work tho !

[cscape]

If the bitfury chips become available again, the higher difficulty requires a cheap board. A design like this has minimal BOM cost, so it will be a good solution.

[cscape]

with hashfast announcing 500 GH / chip .. this is ... dust in the wind ... all respect for your work tho !

What's their total cost for the chip, board, power regulators and cooling system ?

[zulunation]

The other side of the board has 15 different ground planes. The radiator can short them. Do you use a thermal pad between PCB and a heatsink? Or all ground covered with protective mask?

PS: Well done.

[klondike_bar]

didnt a similar design implemented as an H-board have a problem where if a chip shut off, all other chips became overvolted and shut off or melted?

[RoadStress]

If the bitfury chips become available again, the higher difficulty requires a cheap board. A design like this has minimal BOM cost, so it will be a good solution.

Prices for bitfury chips might need to go down too. Can't have those ridiculous prices anymore.

[intron]

The other side of the board has 15 different ground planes. The radiator can short them. Do you use a thermal pad between PCB and a heatsink? Or all ground covered with protective mask?

PS: Well done.

Smart guy:) It's Sil-Pad here.



intron

[intron]

didnt a similar design implemented as an H-board have a problem where if a chip shut off, all other chips became overvolted and shut off or melted?

Yes, you are right. We did that design, but we
didn't operate the board, no idea why it went
down in flames. Our strings board is running
solid now for days and days on end.

intron

[intron]

didnt a similar design implemented as an H-board have a problem where if a chip shut off, all other chips became overvolted and shut off or melted?

As a side note: this string configuration of chips is beyond brilliant,
I think we must honour Valery for this. I have never seen anyone
doing this before. It makes board design so much simpler, elegant
and less costly.

intron

[kaerf]

Very nice. Are you using your own custom miner software?

[goxed]

didnt a similar design implemented as an H-board have a problem where if a chip shut off, all other chips became overvolted and shut off or melted?

As a side note: this string configuration of chips is beyond brilliant,
I think we must honour Valery for this. I have never seen anyone
doing this before. It makes board design so much simpler, elegant
and less costly.

intron

+1

BF is the most integrated chip design of all SHA-256 hashers. It's like Intel Haswell with included clock, Vreg, and logic. What's missing is auto-overclock and p-states just jk.

btw which MCU are you using? Thanks!

[klondike_bar]

didnt a similar design implemented as an H-board have a problem where if a chip shut off, all other chips became overvolted and shut off or melted?

As a side note: this string configuration of chips is beyond brilliant,
I think we must honour Valery for this. I have never seen anyone
doing this before. It makes board design so much simpler, elegant
and less costly.

intron

+1

BF is the most integrated chip design of all SHA-256 hashers. It's like Intel Haswell with included clock, Vreg, and logic. What's missing is auto-overclock and p-states just jk.

btw which MCU are you using? Thanks!

all i can say is: thank god this design does not rely on a Raspberry Pi controller. Somehow my bitfury rig went its first 20 shutdown cycles without any issue, but since then it seems everytime i need to adjust it, the card is damaged. Just today i had to format it, run for 10 min, make the new chainminer, then after a few min of 0.000 results i used sudo reboot and the SD is dead again

[intron]

didnt a similar design implemented as an H-board have a problem where if a chip shut off, all other chips became overvolted and shut off or melted?

As a side note: this string configuration of chips is beyond brilliant,
I think we must honour Valery for this. I have never seen anyone
doing this before. It makes board design so much simpler, elegant
and less costly.

intron

+1

BF is the most integrated chip design of all SHA-256 hashers. It's like Intel Haswell with included clock, Vreg, and logic. What's missing is auto-overclock and p-states just jk.

btw which MCU are you using? Thanks!

A tiny NXP ARM, LPC11U24FHI33/301.

intron

[cscape]

Very nice. Are you using your own custom miner software?

The USB interface protocol is the same as for bi*fury, so the latest cgminer/bfgminer version can be used.