I am estimating the power consumed by my circuit post-synthesis and also post-layout using PrimeTime. I am facing a strange problem regarding the estimated power. The procedure that I follow is:
1. Get VCD file form Modelsim. I use the command “vcd add –r /cpu_test/cpu_inst/*” and run for about sometime.
2. Run the script in Primetime. The script that I use is:
I get different power estimates for different duration of simulation on Modelsim for producing the VCD file. The figures varies from few microwatts to few kilowatts!!! Obviously this doesn’t make any sense. I observed that this difference is because of the power of 10 is different in each case. For e.g. once I get the power estimate as 1.771e-04, for another run I get as 0.0177 and yet another time I get 1.771e+3. This behaviour is same for both post-synthesis and post-layout simulations.
I can’t figure out the mistake that I am making. Can anybody please help?