Altera PowerPlay Early Power Estimator User Manual
Page 25
Column Heading
Description
Toggle%
Enter the average percentage of logic toggling on each clock cycle. The
toggle percentage ranges from 0 to 100%. Typically, the toggle
percentage is 12.5%, which is the toggle percentage of a 16-bit counter.
To ensure you do not underestimate the toggle percentage, use a higher
toggle percentage. Most logic only toggles infrequently; therefore,
toggle rates of less than 50% are more realistic.
For example, a T-flipflop (TFF) with its input tied to VCC has a toggle
rate of 100% because its output is changing logic states on every clock
cycle. Refer to the 4-Bit Counter Example.
Average Fanout
Enter the average number of blocks fed by the outputs of the LUTs and
flipflops.
Thermal Power (W)–Routing
This shows the power dissipation due to estimated routing (in watts).
Routing power depends on placement and routing, which is a function
of design complexity. The values shown represent the routing power
based on experimentation of more than 100 designs.
For detailed analysis based on your design’s routing, use the Quartus II
PowerPlay Analyzer.
Thermal Power (W)–Block
This shows the power dissipation due to internal toggling of the ALMs
(in watts).
Logic block power is a combination of the function implemented and
the relative toggle rates of the various inputs. The PowerPlay EPE
spreadsheet uses an estimate based on observed behavior across more
than 100 real-world designs.
For accurate analysis based on your design’s exact synthesis, use the
Quartus II PowerPlay Analyzer.
Thermal Power (W)–Total
This shows the total power dissipation (in watts). The total power
dissipation is the sum of the routing and block power.
User Comments
Enter any comments. This is an optional entry.
UG-01070
2015.01.20
Logic Worksheet
3-15
PowerPlay Early Power Estimator Worksheets
Altera Corporation