Re: Power calculation using Xpower

All,

The power estimate is only as good as your simulation vectors, and their
length.

Short sims, few vectors = bad estimate.

Austin

John Blaine wrote:

> Praveen,
>
> It is difficult to estimate how much impact this will have on the power
> estimate.
> So let me take you through a few points:
>
> Using a post PAR estimate will allow XPower to have an accurate estimate
> of
> capacitance load on the internal routes so no problem here. If you are
> using post MAP
> where no SDF is generated then this is a large source of inaccuracy and
> is not
> recommended.
>
> Now lets look at the timing simulations tend to result in glitches. This
> switching translates
> into higher activity rates in XPower-> higher power.
>
> I would expect these to be fairly low load signals. Also if you have a
> fully synchronous
> design this effect will be limited.
>
> Your clocks will be set correctly (high power consuming nets).
> If you have met timing (verifed through timing analyser) then other
> heavy loaded signals like
> clock enables, should be set correctly.
>
> So in summary, if your design is post PAR, fully synchronous and has met
> timing, you should
> be OK an get an accurate power estimate.
>
> John
>
> praveen wrote:
>
> > hi all,
> >
> > i am calculating the power consumption using xilinx xpower. For
> > generating the VCD file i am not loading the SDF(Standard Delay
> > Format) during VSIM. Will it affect the power calculation.
> >
> > thanks in advance.