virtex-4 power consumption

Started by October 20, 2007
Now I have ported a design from virtex-2 to virtex-4,because  the
xilinx announced virtex-4 have a lower dynamic power,but actually when
I finished my design,running the same design with virtex-4,the metal
face of the package is hot and this phenomenon is not existed in
virtex-2.Why?Do anybody have the same phenomenon?


First, some easy questions:

1.  Did you simulate the design?
2.  Did you use XPE to estimate the power from your simulation?
3.  Are you running the V4 at its proper voltages?
4.  Have you used the power estimator on the web to estimate the power
required by the IO? (IO power will not scale -- it will not change as
this is something that is identical in your application often)

Now, some more difficult questions:
5.  What was the current on Vccint for the previous part, and what is it
6.  Same question as 5 for Vccaux
7.  Same question as 5 for each Vcco

And finally, which size parts did you use, and are using now?

"Hot" to the touch is not a very precise measure, and this may just be
leakage current (static power), as with no airflow, and no heat sink,
even the static power may make a part "warm" to the touch.

Part to part process variation may have your previous parts with
practically no static power, and the V4 may be at the fast corner of the
process, and have much more leakage (comparatively).