| Dynamic Power Analysis |
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Author: J. Grad
Published: Fri, 14-Oct-2005
Version: 0.09
Article ID: 2
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Read: 6268 times
Article Size: 2.72 KB
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Dynamic Power Analysis
Introduction
There are 2 ways to compute power estimation:
- Statistical Estimate
- Simulation based Estimate
The second method is more acurate and will be
illustrated here.
Example Waveform
Encounter stores the transient power consumption
an a database. The suggested viewer is "nWave",
which ships with Encounter 4.1.
An example transient power waveform:
Encounter Flow
There are 2 major additions to the typical flow:
- Simulate the SDF annotated Encounter netlist and dump VCD
- Load the VCD file back into Encounter for power estimation
The full flow is
- Synthesize RTL
- Run Encounter and
- place & route the design
- write the final netlist, as well as SDF
- save the design database
- Load the netlist in Verilog
- annotate the SDF data
- simulate test vectors
- store the switching activity in VCD
- Run Encounter again and
- reload the database
- read in the VCD file
- do updatePower to get power.rep
Download
The entire example is available for
download.
The scripts have been tested with SOC Encounter 4.1,
PKS or BuildGates 5.0 and Verilog-XL 5.1.
Example Power Report
The power report created by Encounter will
look as follows:
##############################################
# The Power Analysis Report for vdd net #
##############################################
power supply: 1.8 volt
average power between 5.0000e-11 S and 1.9981e-05 S
Total id in vcd file: 66
In module stimulus/dut valid id: 66
redundant id: 0
In module stimulus/dut invalid id: 0
redundant id: 0
Total activity in vcd file: 39894
In module stimulus/dut valid activity: 39894
In module stimulus/dut invalid activity: 0
average power(default): 1.0581e-01 mw
average switching power(default): 5.3705e-02 mw
average internal power(default): 5.2099e-02 mw
average leakage power(default): 2.1384e-06 mw
user specified power(default): 0.0000e+00 mw
average power by cell category:
core: 1.0581e-01 mw
block: 0.0000e+00 mw
io: 0.0000e+00 mw
biggest toggled net: b[0]
no. of terminal: 5
total cap: 7.0651e+01 ff
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