Altera PowerPlay Early Power Estimator User Manual

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Chapter 3: Using Cyclone III PowerPlay Early Power Estimator

PowerPlay Early Power Estimator Inputs

PowerPlay Early Power Estimator User Guide for Cyclone III FPGAs

Toggle %

Enter the average percentage of input, output, and bidirectional pins toggling on each clock
cycle. The toggle percentage ranges from 0 to 200% for input pins used as clocks because
clocks toggle at twice the frequency.

If the pins use a DDR circuitry, you can set the data rate to SDR and double the toggle
percentage. The Quartus II software often uses this method to output information. Typically the
toggle percentage is 12.5%. To be more conservative, you can use a higher toggle percentage.

OE %

Enter the average percentage of time that:

■

Output I/O pins are enabled

■

Bidirectional I/O pins are outputs and enabled

During the remaining time:

■

Output I/O pins are tristated

■

Bidirectional I/O pins are inputs

This number must be a percentage between 0% and 100%.

Load (pF)

Enter the pin loading external to the chip (in pF).

This only applies to outputs and bidirectional pins. Pin and package capacitance is already
included in the I/O model. Therefore, you only need to include off-chip capacitance in the Load
parameter.

Thermal Power (W),
Routing

This shows the power dissipation due to estimated routing (in W).

Routing power is highly dependent on placement and routing, which is itself a function of
design complexity. The values shown are representative of routing power based on
experimentation on over 100 customer designs.

Use the Quartus II PowerPlay Power Analyzer for detailed analysis based on the routing used in
your design. This value is calculated automatically.

Thermal Power (W), Block This shows the power dissipation due to internal and load toggling of the I/O (in W).

Use the Quartus II PowerPlay Power Analyzer for accurate analysis based on the exact I/O
configuration of your design. This value is calculated automatically.

Thermal Power (W), Total

This shows the estimated power (in W), based on the inputs you entered. It is the total power
consumed by the I/O pins and is equal to the sum of the routing power and the block power.
This value is calculated automatically.

Supply Current (A), I

CCINT

This shows the current drawn from the V

CCINT

rail. It powers internal digital circuitry and routing.

This value is calculated automatically.

Supply Current (A), I

CCIO

This shows the current drawn from the V

CCIO

rail. Some of this current may be drawn into

off-chip termination resistors. This value is calculated automatically.

User Comments

Enter any comments. This is an optional entry.

Table 3–6. I/O Section Information (Part 2 of 2)

Parameter

Description