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Topic: - One String - a novel bitfury miner design - - page 3. (Read 21360 times)

sr. member
Activity: 427
Merit: 251
- electronics design|embedded software|verilog -
Fastest USB miner at this moment:





Doing 15+ GH sustained, hex•fury is running
from a 5.5 Volts supply.

intron
sr. member
Activity: 427
Merit: 251
- electronics design|embedded software|verilog -
newbie
Activity: 39
Merit: 0
Hi

Are you able to make me this miner if I get the chips

Cheers
member
Activity: 89
Merit: 10
Had five Ones String boards hashing for some
time, performance looks nice and stable and
no thermal runaways.



intron

Well done folks !
KNK
hero member
Activity: 692
Merit: 502
Did you try placing chips in parallel?
Didn't even tried that. During my tests i have discovered that each chip requires a bit different voltage for optimal speed, but always the same amps, so it's like the chip 'wants' to be serially connected Smiley
Quote
And this 220V string is af course the optimum you
can get in cost efficency:) Looked into a rectifier
for this, it's not easy, mainly due to the current that
is needed.
You need 2-2.5A for the string ... let's make them 3A = 600uF for 0.1V @50Hz it's not that much and expensive, but still, the main ripple regulator should be the current limiter for the string and then each chip for itself (via it's current mirror)

One of the problems is that the grid voltage is not so stable, you need protection from the (kA) spikes, so you will definitely need an UPS (and if it's on-line model with 220V to 110V conversion, you can go with shorter strings), but then you'll loose in efficiency again Sad
The second one is, the string length will reduce the SPI speed and the third one is that RPi (or dedicated MCU) may not be able to drive that much chips

EDIT: Ooops it's 300mF not 600uF, so you are right it will be expensive
sr. member
Activity: 427
Merit: 251
- electronics design|embedded software|verilog -
No, the board was only designed, never made (yet).
As I mentioned, we didn't want to risk a lot of bitfury
chips for just one experiment.
I don't think it will work better than several strings in paralel. The chip seems to like constant current more than constant voltage, but the built in regulator will try to equalize the voltage across paraleled chips and if they are not equal, they will not perform at their best ... and you save nothing more than few resistors on the SPI. I have my strings running on 24V better than on 12V, probably because the current is more stable

I hope the chips will be cheap and freely available in volume soon - my idea is to run the string directly on 220V, which also risks a lot of chips for the experiment, but will save additional 10-20% of power efficiency ... just not sure if RPi will be capable of running 350-400 chips in a string and also there is the lower SPI speed with the increased string length

Did you try placing chips in parallel? I'm also not
sure whether to make seperate strings or connect
all nodes with the same voltage level together.
Biggest challenge is the huge amount of chips you
have to sacrifice for a single experiment that might
run haywire:)

And this 220V string is af course the optimum you
can get in cost efficency:) Looked into a rectifier
for this, it's not easy, mainly due to the current that
is needed.


KNK
hero member
Activity: 692
Merit: 502
No, the board was only designed, never made (yet).
As I mentioned, we didn't want to risk a lot of bitfury
chips for just one experiment.
I don't think it will work better than several strings in paralel. The chip seems to like constant current more than constant voltage, but the built in regulator will try to equalize the voltage across paraleled chips and if they are not equal, they will not perform at their best ... and you save nothing more than few resistors on the SPI. I have my strings running on 24V better than on 12V, probably because the current is more stable

I hope the chips will be cheap and freely available in volume soon - my idea is to run the string directly on 220V, which also risks a lot of chips for the experiment, but will save additional 10-20% of power efficiency ... just not sure if RPi will be capable of running 350-400 chips in a string and also there is the lower SPI speed with the increased string length
sr. member
Activity: 427
Merit: 251
- electronics design|embedded software|verilog -
Had five Ones String boards hashing for some
time, performance looks nice and stable and
no thermal runaways.



intron
full member
Activity: 126
Merit: 100
In the next day or two I should have prototype information available for an interface board designed to break out server supplies for use with miners; these can typically be found for much cheaper than an equivalent output/efficiency ATX supply and usually exhibit better regulation. Screw terminals so you only use what wires you want, and additional output filtering. They're also designed to be run in parallel with load sharing and daisy-chain for automatic power-on in groups.
I have repaired a couple of power supplies used in Supermicro servers (Ablecom forgot the part number). While I still do not know the full pinout of the connector, I found which two traces to short inside to turn it on. Aslong as the power supply is not fully digital, it should not be difficult to use it. Still, the regular ATX PSUs are simpler and easier to fix Smiley
Quote
If enough people want it, I'll look into adding a trimmer to tweak output voltages.
Traditional (not digital) power supplies can be modified to adjust he output voltage just by controlling the feedback. However, if you want the adjustment to be external to the power supply (so you don't need to open the PSU), then youwill have to use a powerful regulator and the total cost will probably be higher than an adjustable PSU.
sr. member
Activity: 427
Merit: 251
- electronics design|embedded software|verilog -
So, now it's time for you to design board with parallel/serial connection of chips Wink
PowerMatrix Wink

We did that already. It's called X-HASH:)

intron

and how did that work?

It takes so many bitfury chips to test it, we were
reluctant to try it. That's why we started with the
smaller strings.

intron

are there any photographs available of said x-hash or was one ever fabbed?

No, the board was only designed, never made (yet).
As I mentioned, we didn't want to risk a lot of bitfury
chips for just one experiment.

intron


hero member
Activity: 658
Merit: 500
CCNA: There i fixed the internet.
So, now it's time for you to design board with parallel/serial connection of chips Wink
PowerMatrix Wink

We did that already. It's called X-HASH:)

intron

and how did that work?

It takes so many bitfury chips to test it, we were
reluctant to try it. That's why we started with the
smaller strings.

intron


are there any photographs available of said x-hash or was one ever fabbed?
legendary
Activity: 3374
Merit: 1859
Curmudgeonly hardware guy
Quote
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.

In the next day or two I should have prototype information available for an interface board designed to break out server supplies for use with miners; these can typically be found for much cheaper than an equivalent output/efficiency ATX supply and usually exhibit better regulation. Screw terminals so you only use what wires you want, and additional output filtering. They're also designed to be run in parallel with load sharing and daisy-chain for automatic power-on in groups.


Quote
The problem with this design is that it requires the 12V power supply to be very well regulated (and adjustable if you want to overclock). Normal ATX PSUs are not that well regulated (ATX spec provides for up to +-5% tolerance on the 12V line (older spec allowed 10%).

If enough people want it, I'll look into adding a trimmer to tweak output voltages.


Been watching this thread; series power dropping chips (if it can be done reliably) is such a darn cool idea and if someone ends up making these boards affordably (and chips are available for not a bajillion dollars) I'll definitely be in the market. Good work, guys.
sr. member
Activity: 427
Merit: 251
- electronics design|embedded software|verilog -
So, now it's time for you to design board with parallel/serial connection of chips Wink
PowerMatrix Wink

We did that already. It's called X-HASH:)

intron

and how did that work?

It takes so many bitfury chips to test it, we were
reluctant to try it. That's why we started with the
smaller strings.

intron
hero member
Activity: 490
Merit: 501
So, now it's time for you to design board with parallel/serial connection of chips Wink
PowerMatrix Wink

We did that already. It's called X-HASH:)

intron

and how did that work?
sr. member
Activity: 427
Merit: 251
- electronics design|embedded software|verilog -
So, now it's time for you to design board with parallel/serial connection of chips Wink
PowerMatrix Wink

We did that already. It's called X-HASH:)

intron
legendary
Activity: 1029
Merit: 1000
So, now it's time for you to design board with parallel/serial connection of chips Wink
PowerMatrix Wink
sr. member
Activity: 251
Merit: 250
The on-board 0.8V, 30A regulator would add about $15-$20 to the design. For 10-15 cards, the money saved would buy a good PSU with voltage trim option.

Either way, the cards work fine if the voltage isn't perfectly regulated. They just run a bit cooler under 12V, and a bit faster/hotter over 12V.
full member
Activity: 126
Merit: 100
The problem with this design is that it requires the 12V power supply to be very well regulated (and adjustable if you want to overclock). Normal ATX PSUs are not that well regulated (ATX spec provides for up to +-5% tolerance on the 12V line (older spec allowed 10%).

On the other hand, I could buy a big well regulated (and adjustable, or at least modify it to be adjustable) 12V PSU and connect a lot of the boards to it. Then it comes to what is cheaper - A standard ATX PSU (I can sometimes get them cheap by taking failed ones and repairing them) and regulators in each board or an expensive PSU and no regulators. I guess the "no regulators" design wins over for large numbers of boards, while the traditional design is better for a few boards.
sr. member
Activity: 251
Merit: 250
i'm still not sure if my concern was fully answered; what makes this board design work when the H-board string design ended in molten plastic and scorched PCB?
We have a better design Smiley
legendary
Activity: 2128
Merit: 1005
ASIC Wannabe
i'm still not sure if my concern was fully answered; what makes this board design work when the H-board string design ended in molten plastic and scorched PCB?
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