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Topic: - One String - a novel bitfury miner design - - page 4. (Read 21360 times)

legendary
Activity: 1904
Merit: 1007
So when, where and how much?

I would like to know that for the 5$/ bitfury chip, because if you are asking about boards, then find out that they don't sell boards. Only the design.
hero member
Activity: 725
Merit: 503
So when, where and how much?
staff
Activity: 4242
Merit: 8672
Fair enough.
sr. member
Activity: 251
Merit: 250
That will change. The chips are going down to $5/chip.

Either they will go to $5/chip and lower, or they will not be sold at all. In the first case, you need a cheap, low-overhead, mining board. In the second case, you don't need a mining board at all.
legendary
Activity: 3878
Merit: 1193
I was attempting and failing to say that the because the chips are so costly the additional electronics are not that substantial

That will change. The chips are going down to $5/chip.
sr. member
Activity: 251
Merit: 250
So far, we have no indication of increased failure rate. The prototypes that we have are rock solid with constant temperature and constant hashing speed. In a couple of weeks, we'll make a few dozen more boards, and we'll see what happens to the failure rate.
staff
Activity: 4242
Merit: 8672
These boards don't have additional electronics. On the contrary, a lot of the expensive components have been removed, and the 2-layer board is cheaper too.
Yes, I know. I was attempting and failing to say that the because the chips are so costly the additional electronics are not that substantial, and considering the reliability concerns the efficiencies gained may not be worth it.  E.g. you save $x on support electronics but increase the failure rate by y% then if its a win or not depends on the price of the chips.

E.g. if chips cost a million dollars a piece and you save $20/chip on electronics at the cost of a 0.01% increase in failures its not a win.
sr. member
Activity: 251
Merit: 250
These boards don't have additional electronics. On the contrary, a lot of the expensive components have been removed, and the 2-layer board is cheaper too.
staff
Activity: 4242
Merit: 8672
Might be a more interesting design if the chips were priced anywhere near the marginal cost of manufacturer, but with them priced like they were solid gold— the cost of the additional electronics and the reliability concerns may outweigh the benefits.
sr. member
Activity: 251
Merit: 250
And it's not just the cost of the components, but also the availability of some of the more exotic ones.

Another factor is the circuit board design. The fast switching DC/DC regulators typically require at least a 4-layer board for good performance. The One String design uses a cheap 2-layer board.
sr. member
Activity: 427
Merit: 251
- electronics design|embedded software|verilog -
Ok, so the selling point on these isn't so much the hashrate as the lower cost of the power supply? You are losing me there. can you give an example of a typical power supply used and a lower cost alternative? I'm not sure what we are talking about.

Just as an example, take a look at the HashFast board: almost
50% is taken up by the DC/DC converting circuitery providing
for the low voltage/high current the chip needs.

In a string design this DC/DC conversion is no longer needed,
so taking up no PCB area and not adding to the Bill of Materials.

intron
sr. member
Activity: 251
Merit: 250
Oh, so the cost savings is in the parts list, not the actual power supply.

Correct. You still need a 12V power supply. Each card draws about 2-2.5 Amps, depending on the exact voltage.
sr. member
Activity: 251
Merit: 250
But this design has a very big disadvantage. If the first chip in the series connection got damaged the other chips doesnt work anymore, too.

That depends on the exact nature of the damage. If the hashing core is damaged (which makes up the biggest part of the chip), the chip may still provide a working connection to the other chips.

It's not much different than low-voltage bitfury designs, such as the H-CARD. In those designs the communication between the chips also forms a chain. Actually, the M-BOARD has 4 H-CARDS with total of 64 chips in each chain.
member
Activity: 86
Merit: 10
But this design has a very big disadvantage. If the first chip in the series connection got damaged the other chips doesnt work anymore, too.
hero member
Activity: 490
Merit: 501
This design uses 12V to power the chips directly. Other designs, such as the H-CARD have an on-board 12V -> 0.8V power regulator with 30-50Amp capability.

In both cases, you need a 12V supply, but for our new board, you avoid the additional cost of the 0.8V regulator.

Oh, so the cost savings is in the parts list, not the actual power supply. The only reason i asked is that i'm getting tired of miners requiring ATX power supplies. Unless you get a modular one you have to deal with a bunch of unneeded cables. also they take up more room than a power brick. Unless you use some sort of case to put your miner in, your work space can become quite messy/unwieldy. This is one of the reasons i won't buy ASICminer Cubes, 1-2 Cubes per powersupply can make for a lot of power supplies laying around. I'm a Hobbyist.
sr. member
Activity: 251
Merit: 250
This design uses 12V to power the chips directly. Other designs, such as the H-CARD have an on-board 12V -> 0.8V power regulator with 30-50Amp capability.

In both cases, you need a 12V supply, but for our new board, you avoid the additional cost of the 0.8V regulator. Also, the 0.8V regulator is typically only about 90% efficient, so it creates 10% more heat for the same hashrate. The powerful switching regulator also produces lots of electrical interference that can degrade reliability of the overall system, and requires additional components (capacitors/inductors) to help reduce the noise.
hero member
Activity: 490
Merit: 501
Ok, so the selling point on these isn't so much the hashrate as the lower cost of the power supply? You are losing me there. can you give an example of a typical power supply used and a lower cost alternative? I'm not sure what we are talking about.
sr. member
Activity: 427
Merit: 251
- electronics design|embedded software|verilog -
We have three One String boards hashing now,
looks like performance is rock solid.

Board temperature well below 45 oC. Hottest
ASIC about 70 oC.




intron

PS: The little blip in the green trace was
cgminer going down and needed restarting:)
vs3
hero member
Activity: 622
Merit: 500
Intron - Is this design based on the same idea that Tytus had:

2. 8-chip cards that were supposed to give more hashrate per chip using the same 30Amp power regulator, this design failed !!! the new PCB was designed as 2 layers and it generates too much noise to connect 2 h-cards in one bank ... so we can use such cards only in the last position of the bank.
3. provisional 5V string designs [no power regulator], this is a very promising design, chips run very clean and fast, but require cooling. If this is not provided or if it fails, chips heat up, leakage increases, chips consume more power and heat up more and melt and burn finally http://150.254.111.246/img/S7300314.JPG, http://150.254.111.246/img/S7300316.JPG ... the chips don't have any thermal sensors so I am still thinking how to detect such problems using the hardware we have.
(in case the images above don't work here are the two images again: http://imgur.com/D7yH26n and http://imgur.com/gqVOtA5 )

and where you later commented that it was an experiment that went out of control -

What's that pic ... the new boards?

and what's that pic ? ^^

http://150.254.111.246/img/S7300314.JPG

It's an experiment that went a bit out of control.
The latest scientific explanation I heard is that
"the boards don't like women." Not really sure
about that though:)

intron

So basically - is it the same design? If so - what has been done (and was there anything done) to avoid the same outcome as tytus' ?

And just out of curiosity - are you guys going to be publishing the design schematics?

this was my concern too, but intron's design has its own controller, so perhaps (hopefully) it is capable of detecting a lost chip and acting (restart the mining process or turn off) so that we dont see a bunch of home fires and molten PCBs

The microcontroller is pretty much irrelevant for that issue.

The issue that Tytus had is the same one that you get with any Christmas lights string - if one light shorts the rest get some extra voltage. If two short, the remaining lights get even more overpowered. And it gets worse and worse even faster until they all melt and/or the fuse blows.
Or if one light burns - they all die.

In tytus' case he was getting the first option - when chips overheat they tend to use more power and then they start overheating even further even faster until they hit the limit and the melting point. At which point you get either a short in one of the chips (and then everything dies very quickly), or the chip cuts the string and again everything dies. Actually my preference would be for the second option - at least the rest of the chips may survive Smiley
Unfortunately (or fortunately?) bitfury's chip has a very solid design, and it's much easier to melt the silicon inside than to burn all of those power wires.

Bitfury said at some point that he gave up on that design (quoting various reasons) but as time goes people may have found a workaround - and if that's the case - lots of respect for intron and co!

And I guess that's the root of my question - is it some novel approach?
legendary
Activity: 2128
Merit: 1005
ASIC Wannabe
Intron - Is this design based on the same idea that Tytus had:

2. 8-chip cards that were supposed to give more hashrate per chip using the same 30Amp power regulator, this design failed !!! the new PCB was designed as 2 layers and it generates too much noise to connect 2 h-cards in one bank ... so we can use such cards only in the last position of the bank.
3. provisional 5V string designs [no power regulator], this is a very promising design, chips run very clean and fast, but require cooling. If this is not provided or if it fails, chips heat up, leakage increases, chips consume more power and heat up more and melt and burn finally http://150.254.111.246/img/S7300314.JPG, http://150.254.111.246/img/S7300316.JPG ... the chips don't have any thermal sensors so I am still thinking how to detect such problems using the hardware we have.
(in case the images above don't work here are the two images again: http://imgur.com/D7yH26n and http://imgur.com/gqVOtA5 )

and where you later commented that it was an experiment that went out of control -

What's that pic ... the new boards?

and what's that pic ? ^^

http://150.254.111.246/img/S7300314.JPG

It's an experiment that went a bit out of control.
The latest scientific explanation I heard is that
"the boards don't like women." Not really sure
about that though:)

intron

So basically - is it the same design? If so - what has been done (and was there anything done) to avoid the same outcome as tytus' ?

And just out of curiosity - are you guys going to be publishing the design schematics?

this was my concern too, but intron's design has its own controller, so perhaps (hopefully) it is capable of detecting a lost chip and acting (restart the mining process or turn off) so that we dont see a bunch of home fires and molten PCBs
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