Dynamic Power Dissipation Calculator
Work out dynamic power dissipation instantly with clear inputs, formula shown and shareable results.
About Dynamic Power Dissipation Calculator
Dynamic power is alpha x C x V squared x f. The quadratic voltage term is why dynamic voltage and frequency scaling is so effective: dropping from 1.0 V to 0.85 V cuts power by 28% at the same frequency, and reducing frequency lets voltage drop further still.
Formula
Dynamic power
P = alpha x C x V^2 x f
Worked example
With the default values below, Dynamic Power Dissipation Calculator returns Dynamic power of 8.74. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Switched capacitance
- 42 nF
- Supply voltage
- 0.85 V
- Clock frequency
- 2.4 GHz
- Activity factor
- 0.12
Results
- Dynamic power
- 8.74 W
- Energy per cycle
- 3.64140 nJ
- Power at 1.0 V
- 12.10 W
- Saving versus 1.0 V
- 27.75% %
Step by step
- 1Values used
- 2Dynamic power
- 3Dynamic power= 8.74 W
- 4Energy per cycle= 3.64140 nJ
- 5Power at 1.0 V= 12.10 W
- 6Saving versus 1.0 V= 27.75 %
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax or fees or charges into account.
- Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
Why is DVFS so effective?
Power falls with V squared while performance falls only linearly with frequency, so reducing both gives a roughly cubic power saving for a linear performance loss.
What is the activity factor?
The average fraction of clock cycles on which a node toggles. Typical logic is 0.05-0.15; the clock itself is 1.0.
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