For
a net,
where C is the total capacitive loading of the net (extracted from
the routing topology), V is the net's voltage swing, and F is the average
switching frequency.
SmartPower calculates two power values for your design:
Static Power: This value is a summation of the static power consumed by each element of the design. SmartPower provides a Static power consumption of the array. This value is die dependent. For ProASIC3/E and Axcelerator families, SmartPower also provides a static power consumption per I/O. This value is I/O standard dependent.
Dynamic Power: This value is a summation of the dynamic power consumed by each element of the design (nets, modules, I/Os, RAM, FIFO, PLL, etc.).
SmartPower calculates power consumption in Worst, Typical, or Best Operating conditions.
SmartPower uses the following as general guidelines:
It applies a voltage derating to dynamic power contributions. Higher voltage typically leads to worst power.
It applies a temperature derating to static power contributions. Higher temperature typically leads to worst power.
It applies no radiation derating.
Note: The examples below are for general evaluation purposes only. They are not a precise representation of the actual calculations, since each calculation takes into account family-specific information.
For
a net,
where C is the total capacitive loading of the net (extracted from
the routing topology), V is the net's voltage swing, and F is the average
switching frequency.
Note: For ProASICPLUS family, SmartPower extracts the capacitive loading of a net from a Wire Load model.
For
a module, the power is computed
using a characterized library (by family and die-size) describing a specific
power model for each type of module. For example, the power model of a
flip-flop is given by
where FCK is the average clock-input
frequency for this flip-flop, FDOUT
is its average data-output frequency, and PCK,
PDOUT,
PDin
are three constants estimated by electrical simulation and silicon
characterization for this flip-flop module, and FDin
is its average data-input frequency.
For
an I/O, the formula used for computing
the power consumption depends on the I/O technology and the family. For
example, for a TTL output, the dynamic power is given by
where C is the output load (derived from what you have set in the PinEditor
GUI, typically 35 pF for TTL), V is the output's voltage swing (3.3 V
for TTL), and PINT represents
an internal power contribution dissipated in the pad, and F is the average
switching frequency of the I/O.
For a complex block, like a RAM, a FIFO, or a PLL, SmartPower uses a high-level power model that integrates design parameters.
SmartPower automatically computes all the constant parameters of these equations. However, the frequencies depend on the target frequencies of your design. Since it is impractical to enter each frequency manually, SmartPower has several flows that help you to estimate the frequencies and calculate the power consumption.