Just what is a clock buffer anyway? - page 6.

bitmar

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Quote from: eldentyrell on November 29, 2012, 06:16:08 AM

It's what you add when you don't have chips.

you can also increase speed (for example from 40GH to 60 GH.) or improve power consumption or give a false date of shipment or be unpleasant for customers or troll competition. You can do a lot of things when you do not have chips Wink

eldentyrell

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felonious vagrancy, personified

It's what you add when you don't have chips.

ab8989

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FUTURE OF CRYPTO IS HERE!

The most accurate non-technical synonym I could think of is repeater or amplifier. The clock needs to be routed from one input pin into thousands or millions gates inside the chip that need clock and to do that there is a thing called clock-tree inside the chip, where the single input clock is divided into these millions of consumers. You cannot just use one metal connector strip to do that since the millions of consumers would each get just a tiny fraction of the input voltage or current available and that is obviously not going to be enough. Therefore you are forced to insert buffers ( repeaters ) into this clock tree to regenerate the clock signal characteristics as they degrade when the signal is being split. There are multiple layers of these buffers feeding another buffers feeding another buffers in the tree.

pieppiep

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You can think of an electric circuit like a network of waterpipes.
When you need a high level of water on the other side of the pipe you let water in. You try to keep the level at a certain hight at the beginning, water will flow until the level at the end is the same.
The same happens with electricity, but much faster. You rise the voltage at one end, current starts flowing and the voltage rises at the other end.
The parts in a chip for the calculation are usually very close together, so you just need a little current and a short time to rise the voltage.
The clock signal however, is needed at many places so the current to rise the voltage in many endpoints needs to be a lot higher.
The clock signal is not like a single pipe that needs to be filled with water, but a complete network of many pipes.
If you cut the pipe network into smaller pieces, the smaller pieces are filled much faster. At the end of the smaller pieces you place a device that will open a watertap to fill the part after it.
The clock buffer is something like this, it reacts on the clock and outputs more current than it receives so that the circuit can have a big clock network.

mightycount

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It's something you add when you don't have a chip.. Eh?

goxed

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Bitcoin / Crypto mining Hardware.

http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/buffer.html#c2

abeaulieu

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Buffers themselves usually are implemented to keep noise from feeding back into another system or to create a delay in the signal (hinted at by the name buffer). A clock buffer is implemented more specifically to control rise and fall time of clock edges (google "slew rate"). This allows for the clock to be fanned out with more stability and less jitter.

Keninishna

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I don't know physically what they will use for a clock buffer but the idea is to improve the signal and reduce noise. Like intel uses 3d tri-gate resistor tech as well as the use of the element hafnium to help with the clock at smaller die sizes. I could be a bit off but this is my understanding.

Bogart

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Quote from: BFL-Engineer on November 28, 2012, 09:42:08 AM

Hi Everyone,

We've been very busy recently, unfortunately I couldn't catch up with the forums. There is a correction to be made: Chips are not and were not flawed. We decided to add certain clock buffers to improve noise-resistance and possibly increase frequency even further. The improve in noise resistance was our real goal (average frequency increase across a full wafer can be a bi-product). The decision was made to increase the near 100% chance of success even more. We'll keep you posted. If you had any questions, please let us know.

Regards,
Nasser

So just what is a clock buffer? What does one do, where is BFL likely to be adding them to their product, how many will they be adding, and why that number and location?

From the name, I can imagine some of the things one might do. I could just google it, but discussing it here sounds like more fun.

Discuss.

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