[Cryptech Core] FPGA Power Estimation

[Peter Stuge]

Fredrik Thulin wrote:
> Is there a problem with designing according to your (Pavel's)
> suggestion, and then do some actual measurements when we have
> things running, to maybe be able to scale down the power subsystem
> for a subsequent design?

Building a high performance car is more difficult than building a
medium performance car. Same with power supplies. But there is a
reference which can be copied, which helps a lot.

Possibly just modify it to have test points for measuring actual draw.


> PS. It used to be 110 km/h until just a few years ago.

One part of E6 (Malmö-Göteborg) has been 120 km/h for over a decade.
It was the test site to find out whether Swedes self-ignite when traveling
at that speed.


Jacob wrote:
> If one takes the values above as realistic FPGA design values

I don't think anyone suggested that. It is clear that the reference
board power supply is most likely far more powerful than what the
alpha board will require.


> heat sinking and box ventilation

Quite the opposite. Since the reference will most likely be greatly
overdimensioned for the workload, heat dissipation doesn't even need
to be considered.


> I don't see any other way

Use the overdimensioned reference design with inadequate cooling and
measure what real workloads need. Speculation and estimation at this
point seems premature optimization.

If the reference design is inconvenient then look around for other
designs with slightly lower performance.


Please always keep licensing in mind. Everyone must be aware that the
project must be able to publish all design material under a very
permissive license.

I have already found Xilinx proprietary code for a test bench in the
very first repo I looked at - that is not in any way compatible with
the project goal of using BSD or a similarly permissive license.

This project is *not* comparable with ordinary commercial projects.

Please also remember that most reference designs found on the
internet are unlikely to be compatible with BSD. Did anyone check
what license the Xilinx reference board uses, before considering it
an option?


//Peter