powerplay analyzer help

[ihjay]

hi could it be possible that 4 bit carry save multiplier power consumption is larger than 8 bit using powerplay power analyzer?
i used gate level modeling for the codes. it happen that 4 bit has a power consumption of 133.28mW while 8 bit is 132.92mW is this possible?
thanks

 

[ads-ee]

hi could it be possible that 4 bit carry save multiplier power consumption is larger than 8 bit using powerplay power analyzer?
i used gate level modeling for the codes. it happen that 4 bit has a power consumption of 133.28mW while 8 bit is 132.92mW is this possible?
thanks

No, it shouldn't be.

You've probably run a testcase with the toggling of the signals on your gate level VCD dump that has nearly equivalent toggling of signals in the 4-bit and 8-bit cases. Your test isn't representative of the power for either design.

You probably want to run an exhaustive test on the 4-bit case (256 possible results of the multiply) and something less exhaustive for the 8-bit multiplier. Feed that into your powerplay analysis and you'll likely see significantly different results.

Don't ask me how to do all this, I haven't used Altera and powerplay for more than 5 years.

Regards

 

[ihjay]

thank you very much.