Describes how to set up and use the PowerPlay Early Power Estimator to estimate power for your designs.

PowerPlay Early Power Estimator for Altera CPLDs User
Guide
PowerPlay Early Power Estimator for Altera CPLDs
User Guide
101 Innovation Drive
San Jose, CA 95134
www.altera.com
UG-01093-1.0
Document last updated for Altera Complete Design Suite version:
Document publication date:
10.1
December 2010
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PowerPlay Early Power Estimator for Altera CPLDs User Guide
December 2010
Altera Corporation
Contents
Chapter 1. PowerPlay Early Power Estimator Overview
Setting Up the PowerPlay EPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–1
Download and Install the PowerPlay EPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–1
Estimating Power Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–2
Estimating Power Consumption Before Starting the CPLD Design . . . . . . . . . . . . . . . . . . . . . . . . 1–3
Estimating Power Consumption While Creating the CPLD Design . . . . . . . . . . . . . . . . . . . . . . . . 1–3
Estimating Power Consumption After Completing the CPLD Design . . . . . . . . . . . . . . . . . . . . . . 1–4
Entering Information into the PowerPlay Early Power Estimator . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–4
Clearing All Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–4
Manually Entering Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–4
Importing a File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–4
Chapter 2. PowerPlay Early Power Estimator Worksheets
Power Estimation Using the PowerPlay Early Power Estimator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–1
Main Worksheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–1
Input Parameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–2
Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–3
Thermal Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–4
Power Supply Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–5
Other Input Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–5
Core Worksheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–6
Clock Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–6
Logic Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–7
User Flash Memory Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–9
I/O Worksheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–9
Factors Affecting the PowerPlay Early Power Estimator Spreadsheet Accuracy . . . . . . . . . . . . . . . . . 2–13
Toggle Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–13
Airflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–14
Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–15
Chapter 3. Power Saving Techniques
Additional Information
Document Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Info–1
How to Contact Altera . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Info–1
Typographic Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Info–1
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PowerPlay Early Power Estimator for Altera CPLDs User Guide
iv
PowerPlay Early Power Estimator for Altera CPLDs User Guide
Contents
December 2010
Altera Corporation
1. PowerPlay Early Power Estimator
Overview
This user guide describes the PowerPlay Early Power Estimator (EPE) support for
MAX® II and MAX V device families and provides a step-by-step explanation of how
to use this tool at any stage of the CPLD design. There are also details about thermal
analysis and the factors that contribute to CPLD power consumption. You can
calculate the CPLD power with the Microsoft Excel-based PowerPlay EPE
spreadsheet or the PowerPlay Power Analyzer in the Quartus® II software by entering
the device resources, operating frequency, toggle rates, and other parameters into the
PowerPlay EPE spreadsheet.
1
Altera recommends using these calculations as an estimation of power, not as a
specification. It is important that you verify the actual power during device operation
as the information is sensitive to the actual device design and the environmental
operating conditions.
f For more information about available device resources, I/O standard supports, and
other device features, refer to the respective device family handbook.
The features of the PowerPlay EPE spreadsheet include:
■
Estimating the power consumption of your design before creating the design or
during the design process
■
Importing device resource information from the Quartus II software into the
PowerPlay EPE spreadsheet with the use of the Quartus II-generated PowerPlay
EPE file
■
Performing preliminary thermal analysis of your design
Setting Up the PowerPlay EPE
This section describes how to set up the PowerPlay EPE, estimating power
consumption, and entering information into the PowerPlay EPE spreadsheet.
Download and Install the PowerPlay EPE
f The PowerPlay EPE spreadsheet for Altera® devices is available from the PowerPlay
Early Power Estimators (EPE) and Power Analyzer on the Altera website. You can
download the Microsoft Excel (.xls) file and begin the power analysis for your
designs.
By default, the macro security level in Microsoft Excel 2003 and Microsoft Excel 2007
is set to High and macros are automatically disabled. For the features in the
PowerPlay EPE spreadsheet to function properly, you must enable macros.
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PowerPlay Early Power Estimator for Altera CPLDs User Guide
1–2
Chapter 1: PowerPlay Early Power Estimator Overview
Setting Up the PowerPlay EPE
To change the macro security level in Microsoft Excel 2003, perform the following
steps:
1. On the Tools menu, click Options.
2. On the Security tab, click Macro Security.
3. On the Security Level tab of the Security dialog box, choose Medium. Click Ok.
4. On the Options window, click Ok.
5. Close the PowerPlay EPE spreadsheet and reopen it.
6. A pop-up window asks you whether or not to enable macros each time you open a
spreadsheet that contains macros, click Enable Macros.
To change the macro security level in Microsoft Excel 2007, perform the following
steps:
1. Click the Office button in the upper left corner of the .xlsx file.
2. At the bottom of the menu, click Excel Options.
3. Click Trust Center on the left and then click Trust Center Settings.
4. In the Trust Center dialog box, click Macro Settings. Turn on the Disable all
macros with notification option.
5. Close the PowerPlay EPE spreadsheet and reopen it.
6. A security warning appears beneath the Office ribbon. Click Options.
7. In the Microsoft Office Security Options dialog box, turn on Enable this content.
Estimating Power Consumption
You can use the PowerPlay EPE spreadsheet to estimate the power consumption at
any point of your design cycle. You can use the PowerPlay EPE spreadsheet to
estimate the power consumption if you have not begun your design, or if your design
is not complete.
1
While the PowerPlay EPE spreadsheet can provide you with an estimate for your
complete design, Altera recommends using the PowerPlay Power Analyzer in the
Quartus II software to obtain this estimate for your complete design because the
PowerPlay Power Analyzer can give you a more accurate analysis of your exact
routing and the various modes of operation.
PowerPlay Early Power Estimator for Altera CPLDs User Guide
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Altera Corporation
Chapter 1: PowerPlay Early Power Estimator Overview
Setting Up the PowerPlay EPE
1–3
Estimating Power Consumption Before Starting the CPLD Design
Table 1–1 lists the advantage and disadvantages of using the PowerPlay EPE
spreadsheet before you begin your CPLD design.
Table 1–1. Power Estimation Before Designing CPLD
Advantage
■
Disadvantage
You can obtain power estimation before
starting your CPLD design.
■
Accuracy depends on your inputs and your
estimation of the device resources; where this
information may change (during or after your
design is complete), your power estimation
results may be less accurate.
■
Process can be time consuming.
To estimate power consumption using the PowerPlay EPE spreadsheet before starting
your CPLD design, perform the following steps:
1. On the Main worksheet of the PowerPlay EPE spreadsheet, select the target family,
device, and package from the Device and Package drop-down list.
2. Enter values for each worksheet in the PowerPlay EPE spreadsheet. Different
worksheets in the PowerPlay EPE spreadsheet display different power sections,
such as clocks and I/Os.
3. The calculator displays the estimated power consumption in the Total column.
Estimating Power Consumption While Creating the CPLD Design
If your CPLD design is partially complete, you can import the PowerPlay EPE file
(<revision name>_early_pwr.csv) generated by the Quartus II software to the
PowerPlay EPE spreadsheet. After importing the information from the
<revision name>_early_pwr.csv file into the PowerPlay EPE spreadsheet, you can edit
the PowerPlay EPE spreadsheet to reflect the device resource estimates for your final
design.
Table 1–2 lists the advantage and disadvantages if you use the PowerPlay EPE
spreadsheet for a CPLD design that is partially complete.
Table 1–2. Power Estimation if Your CPLD Design is Partially Complete
Advantage
Disadvantage
■
You can perform power estimation early in
the CPLD design cycle.
■
Provides the flexibility to automatically fill in
the PowerPlay EPE spreadsheet based on the
Quartus II software compilation results.
■
Accuracy depends on your inputs and your
estimation of the device resources; where this
information may change (during or after your
design is complete), your power estimation
results may be less accurate.
■
Process can be time consuming.
To estimate power consumption with the PowerPlay EPE spreadsheet if your CPLD
design is partially complete, refer to “Importing a File” on page 1–4.
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PowerPlay Early Power Estimator for Altera CPLDs User Guide
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Chapter 1: PowerPlay Early Power Estimator Overview
Setting Up the PowerPlay EPE
Estimating Power Consumption After Completing the CPLD Design
If your design is complete, Altera recommends using the PowerPlay Power Analyzer
in the Quartus II software. The PowerPlay Power Analyzer provides the most
accurate estimate of device power consumption. To determine power consumption,
the PowerPlay Power Analyzer uses simulation, user mode, and default toggle rate
assignments, in addition to placement-and-routing information.
f For more information about the power estimation feature, how to use the PowerPlay
Power Analyzer, and generating the PowerPlay EPE file in the Quartus II software,
refer to the PowerPlay Power Analysis chapter in volume 3 of the Quartus II Handbook.
Entering Information into the PowerPlay Early Power Estimator
You can either manually enter power information into the PowerPlay EPE
spreadsheet or load a PowerPlay EPE file generated by the Quartus II software. You
can also clear all current values in the PowerPlay EPE spreadsheet.
To use the PowerPlay EPE spreadsheet, enter the device resources, operating
frequency, toggle rates, and other parameters in the PowerPlay EPE spreadsheet. If
you do not have an existing design, you must estimate the number of device resources
your design uses and enter the information into the PowerPlay EPE spreadsheet.
Clearing All Values
You can reset all the user-entered values in the PowerPlay EPE spreadsheet by
clicking the Reset button.
1
To use the Reset feature, you must enable macros for the spreadsheet. If you have not
enabled macros for the spreadsheet, you must manually reset all the user-entered
values.
Manually Entering Values
You can manually enter values into the PowerPlay EPE spreadsheet in the appropriate
section. White unshaded cells are input cells that you can modify. Each section
contains a column that allows you to specify a module name based on your design.
Importing a File
Importing a file saves you time and effort otherwise spent on manually entering
information into the PowerPlay EPE spreadsheet. You can also manually change any
of the values after importing a file.
To generate the PowerPlay EPE file, perform the following steps:
1. Compile the partial CPLD design in the Quartus II software.
2. On the Project menu, click Generate PowerPlay Early Power Estimator File to
generate the <revision name>_early_pwr.csv file in the Quartus II software.
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Chapter 1: PowerPlay Early Power Estimator Overview
Setting Up the PowerPlay EPE
1–5
To import the Quartus II file into the PowerPlay EPE spreadsheet, perform the
following steps:
1. In the PowerPlay EPE spreadsheet, click Import QII File.
2. Browse to a PowerPlay EPE file generated from the Quartus II software and click
Open. The file has a name of <revision name>_early_pwr.csv.
3. In the confirmation window, click OK.
4. If the file is imported, click OK. Clicking OK acknowledges the import is
complete. If there are any errors during the import, an .err file is generated with
details.
1
You must import the PowerPlay EPE file into the PowerPlay EPE
spreadsheet before modifying any information in the PowerPlay EPE
spreadsheet. Also, you must verify all your information after importing a
file.
To import the EPE file into the PowerPlay EPE spreadsheet, perform the following
steps:
1. In the PowerPlay EPE spreadsheet, click Import EPE.
2. Browse to a PowerPlay EPE spreadsheet file (.xls) and click Open.
3. In the confirmation window, click OK.
Importing the Quartus II PowerPlay EPE file or the PowerPlay EPE spreadsheet from
the Quartus II software populates all input values on the Main worksheet as
per specified in the Quartus II software. These parameters include:
■
Device
■
Package
■
Temperature grade
■
Power characteristics
■
V CCINT supply voltage
■
Ambient temperature, TA (°C)
■
Airflow
f For more information about these parameters, refer to “Main Worksheet” on page 2–1.
The clock frequency (fMAX) values imported into the PowerPlay EPE spreadsheet are
the same as the fMAX values taken from the Quartus II software as per the design. You
can manually edit the fMAX values and the toggle percentage in the PowerPlay EPE
spreadsheet to suit your design requirements.
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PowerPlay Early Power Estimator for Altera CPLDs User Guide
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PowerPlay Early Power Estimator for Altera CPLDs User Guide
Chapter 1: PowerPlay Early Power Estimator Overview
Setting Up the PowerPlay EPE
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2. PowerPlay Early Power Estimator
Worksheets
This chapter describes how to evaluate and manage MAX II and MAX V power using
the PowerPlay EPE spreadsheet.
This chapter contains the following sections:
■
“Power Estimation Using the PowerPlay Early Power Estimator” on page 2–1
■
“Factors Affecting the PowerPlay Early Power Estimator Spreadsheet Accuracy”
on page 2–13
Power Estimation Using the PowerPlay Early Power Estimator
This section provides information about each worksheet of the PowerPlay EPE
spreadsheet. The PowerPlay EPE spreadsheet provides the ability to enter
information into worksheets based on architectural features. The PowerPlay EPE
spreadsheet also provides a subtotal of power consumed by each architectural feature
and is reported in each worksheet in mWatts (mW).
Main Worksheet
The Main worksheet of the PowerPlay EPE spreadsheet summarizes the power and
current estimates for the design. The Main worksheet displays the total thermal
power, thermal analysis, and power supply sizing information.
Figure 2–1 shows the Main worksheet of the PowerPlay EPE spreadsheet.
Figure 2–1. Main Worksheet of the PowerPlay EPE Spreadsheet
Thermal Analysis
Information
Power Supply Sizing
Information
Input Parameter Information
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Power Information
PowerPlay Early Power Estimator for Altera CPLDs User Guide
2–2
Chapter 2: PowerPlay Early Power Estimator Worksheets
Power Estimation Using the PowerPlay Early Power Estimator
1
Only use the results obtained as an estimation of power, not as a specification of
power. The actual ICC must be verified during device operation, as this measurement
is sensitive to the actual pattern in the device and the environmental operating
conditions.
The accuracy of the power estimation depends on the information you enter. The
power consumed can also vary depending on the toggle rates you enter. The
following sections describe the sections in the Main worksheet of the PowerPlay EPE
spreadsheets.
Input Parameter
Different MAX II and MAX V devices consume different amounts of power for the
same design. The larger the device, the more power it consumes because of a larger
clock tree.
Table 2–1 lists the values you must specify in the Input Parameter section in the Main
worksheet of the PowerPlay EPE spreadsheet, as shown in Figure 2–1.
Table 2–1. Input Parameter Section Information
Input Parameter
Description
Select your device.
Device
Larger devices consume more static power and have higher clock dynamic power. All power
components are unaffected by the device you use.
Select the package that you are using.
Package
Larger packages provide a larger cooling surface and more contact points to the circuit board,
leading to lower thermal resistance. Package selection does not affect dynamic power.
Select the appropriate temperature grade. This field only affects the allowed maximum junction
temperature range.
Temperature Grade
Power Characteristics
Different device families support different temperature grades. For more information about the
supported temperature grade and the recommended operating range for the device junction
temperature, refer to the DC and Switching Characteristics chapter in the MAX II Device
Handbook and the DC and Switching Characteristics for MAX V Devices chapter in the MAX V
Device Handbook.
Select the typical or theoretical worst-case silicon process.
There is a process variation from die-to-die. This primarily impacts static power consumption.
VCCINT Supply Voltage
The voltage of the VCCINT power supply. For MAX IIG, MAX IIZ, and MAX V devices, the supply
voltage is 1.8 V. For other MAX II devices, it can be either 2.5 V or 3.3 V. Devices with lower
VCCINT have lower total standby power consumption.
Ambient Temperature,
TA (°C)
Enter the air temperature near the CPLD device. This value can range from –40°C to 125°C,
depending on the device temperature grade. This parameter is used to compute junction
temperature based on power dissipation and thermal resistances through the top of the chip.
Airflow
Select an available ambient airflow in linear-feet per minute (lfm) or meters per second (m/s).
The values are 100 lfm (0.5 m/s), 200 lfm (1.0 m/s), 400 lfm (2.0 m/s), or Still Air.
Increased airflow results in a lower junction-to-air thermal resistance and lowers the junction
temperature.
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Chapter 2: PowerPlay Early Power Estimator Worksheets
Power Estimation Using the PowerPlay Early Power Estimator
2–3
Power
This section describes the power dissipated in the MAX II and MAX V devices. The
total thermal power is shown in mWatts and is a sum of the thermal power of all the
resources being used in the device.
Table 2–2 lists the thermal power parameters in the PowerPlay EPE spreadsheet, as
shown in Figure 2–1 on page 2–1.
Table 2–2. Power Section Information
Column Heading
Description
Clocks
Represents the dynamic power consumed by the clock networks. To view the details, click
Clocks.
Logic
Represents the dynamic power consumed by the logic elements (LEs) and associated routing. To
view the details, click Logic.
UFM
Represents the dynamic power consumed by the UFM block. To view the details, click UFM.
I/O
Represents the dynamic power consumed by the I/O pins and associated routing. To view the
details, click I/O.
PSTANDBY
Represents the static power consumed irrespective of the clock frequency. The value includes
static power consumed by the I/O banks and the voltage regulator.
PSTANDBY depends on the device you select and the VCCINT supply voltage.
PTOTAL
December 2010
Represents the total power consumed by the CPLD device. For more information about the
current draw from the CPLD supply rails, refer to “Power Supply Current” on page 2–5.
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Chapter 2: PowerPlay Early Power Estimator Worksheets
Power Estimation Using the PowerPlay Early Power Estimator
Thermal Analysis
To determine the junction temperature (TJ) of the device in °C, the ambient
temperature and airflow are taken into consideration by the PowerPlay EPE
spreadsheet.
The device is considered a heat source and the junction temperature is the
temperature at the device. The thermal resistance of the path is referred to as the
junction-to-ambient thermal resistance (JA). Figure 2–2 shows the thermal model for
the PowerPlay EPE spreadsheet.
Figure 2–2. PowerPlay Early Power Estimator Thermal Model
Heat Source
Power (P)
TJ
qJA
TA
The PowerPlay EPE spreadsheet determines the JA based on the device, package, and
airflow selected in the input parameters section.
The PowerPlay EPE spreadsheet calculates the total power based on the device
properties which provide JA and the ambient and junction temperature, as shown in
Equation 2–1.
Equation 2–1.
TJ – T A
P = ---------------- JA
Table 2–3 lists the thermal analysis parameters in the PowerPlay EPE spreadsheet, as
shown in Figure 2–1 on page 2–1.
Table 2–3. Thermal Analysis Section Information
Column Heading
Description
Junction Temp, TJ (°C)
Represents the device junction temperature estimation based on the supplied thermal
parameters.
JA Junction-Ambient
Represents the junction-to-ambient thermal resistance between the device and the ambient air
(in °C/W).
Maximum Allowed TA (°C)
Represents a guideline for the maximum ambient temperature (in °C) that you can subject the
device to without violating the maximum junction temperature, based on the supplied cooling
solution and device temperature grade.
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Chapter 2: PowerPlay Early Power Estimator Worksheets
Power Estimation Using the PowerPlay Early Power Estimator
2–5
Power Supply Current
The power supply current, shown in mA, provides the estimated current
consumption for power supplies. The ICCPOWERUP is only applicable during power up
when the configuration flash memory (CFM) block downloads to the SRAM. The
ICCINT current is the supply current required from VCCINT. The total ICCIO current is the
supply current required from V CCIO for all I/O banks. For more information about the
estimates of ICCIO based on I/O banks, refer to the “I/O Worksheet” on page 2–9.
Table 2–4 lists the power supply current parameters in the PowerPlay EPE
spreadsheet, as shown in Figure 2–1 on page 2–1.
Table 2–4. Power Supply Current Section Information
Column Heading
Description
ICCPOWERUP
Represents the maximum current drawn during power up.
ICCINT
Represents the total current drawn from the ICCINT supply.
ICCIO
Represents the total current drawn from the ICCIO power rails. For more information about the
current drawn from each I/O rail, refer to “I/O Worksheet” on page 2–9.
Other Input Section
Figure 2–3 shows the four buttons under the other input parameters section in the
PowerPlay EPE spreadsheet.
Figure 2–3. Other Input Section in PowerPlay EPE Spreadsheet
Table 2–5 lists the four buttons under the other input parameters section in the
PowerPlay EPE spreadsheet.
Table 2–5. Other Input Section Information
Column Heading
Description
Set Toggle %
Sets the toggle rate for the “Logic Section” on page 2–7 and “I/O Worksheet” on page 2–9.
Reset
Clears all input values in the PowerPlay EPE spreadsheet.
Import QII File
For more information about how to import the Quartus II File, refer to “Entering Information
into the PowerPlay Early Power Estimator” on page 1–4.
Import EPE
For more information about how to import the EPE spreadsheet, refer to “Entering Information
into the PowerPlay Early Power Estimator” on page 1–4.
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Chapter 2: PowerPlay Early Power Estimator Worksheets
Power Estimation Using the PowerPlay Early Power Estimator
Core Worksheet
The Core worksheet of the PowerPlay EPE spreadsheet includes the clock, logic, and
user flash memory (UFM) sections.
Clock Section
MAX II and MAX V devices have four global clocks each. Each row in the Clock
worksheet of the PowerPlay EPE spreadsheet represents a clock network or a separate
clock domain. Enter the following parameters for each design module:
■
Clock frequency (in MHz)
■
Total fanout for each clock network you use
■
Local clock enable percentage
Figure 2–4 shows the Clock section in the PowerPlay EPE spreadsheet.
Figure 2–4. Clock Section in the PowerPlay EPE Spreadsheet
Table 2–6 lists the values you must specify in the Clock section of the PowerPlay EPE
spreadsheet.
Table 2–6. Clock Section Information
Column Heading
Description
Clock Domain
Specify a name for the clock network in this column. This is an optional value.
Clock Freq (MHz)
Enter the frequency of the clock domain. This value is limited by the maximum frequency
specification for the device family.
Total Fanout
Enter the total number of LE flipflops fed by this clock. The number of resources driven by
every global clock is reported in the Fan-out column of the Quartus II Compilation Report. In
the Compilation Report, select Filter and click Resources Section. Select Global and Other
Fast Signals and click Fan-out.
Enter the average percentage of time that clock enable is high for the destination flipflops.
Local Enable %
Local clock enables for flipflops in LEs are promoted to logic array block (LAB)-wide signals.
When you disable a given flipflop, the LAB-wide clock is disabled, cutting clock power and the
power for down-stream logic. This worksheet models only have impact on the clock tree
power.
Total Power (mW)
This is the total power dissipation due to clock distribution.
User Comments
Enter any comments. This is an optional value.
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Chapter 2: PowerPlay Early Power Estimator Worksheets
Power Estimation Using the PowerPlay Early Power Estimator
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Logic Section
A design is a combination of several design modules operating at different
frequencies and toggle rates. Each design module can have a different amount of
logic. For the most accurate power estimation, partition the design into different
design modules. Each row in the Logic section of the PowerPlay EPE spreadsheet
represents a separate design module.
Figure 2–5 shows the Logic section in the PowerPlay EPE spreadsheet.
Figure 2–5. Logic Section in the PowerPlay EPE Spreadsheet
Table 2–7 lists the parameters in the Logic section of the PowerPlay EPE spreadsheet.
Table 2–7. Logic Section Information (Part 1 of 2)
Column Heading
Logic Module
Specify a name for each module of the design. This is an optional value.
Clock Freq (MHz)
# LEs
Description
Enter a clock frequency (in MHz). This value is limited by the maximum frequency specification
for the device families.
100 MHz with a 12.5% toggle means that each look-up table (LUT) or flipflop output toggles
12.5 million times per second (100  12.5%).
Enter the number of LEs in this module.
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.
Toggle %
December 2010
For example, a 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 Figure 2–6). Figure 2–7 shows an example of
a 4-bit counter. The first TFF with LSB output cout0 has a toggle rate of 100% because the
signal toggles on every clock cycle. The toggle rate for the second TFF with output cout1 is
50% because the signal only toggles on every two clock cycles. Consequently, the toggle rate
for the third TFF with output cout2 and the fourth TFF with output cout3 are 25% and 12.5%,
respectively. Therefore, the average toggle percentage for this 4-bit counter is
(100 + 50 + 25 + 12.5)/4 = 46.875%.
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Table 2–7. Logic Section Information (Part 2 of 2)
Column Heading
Description
This shows the power of dissipation due to the estimated routing.
Routing power depends on placement-and-routing information, which is a function of your
design complexity. The values shown represent the routing power based on experimentation of
more than 100 designs.
Routing
For detailed analysis based on your design’s routing, use the Quartus II PowerPlay Analyzer.
This shows the power dissipation due to the internal toggling of the LEs.
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 an observed
behavior across more than 100 designs.
Block
For accurate analysis based on your design’s exact synthesis, use the Quartus II PowerPlay
Analyzer.
Total
This shows the total power dissipation. The total power dissipation is the sum of the routing
and block power.
User Comments
Enter any comments. This is an optional value.
Figure 2–6 shows the T-Flipflop.
Figure 2–6. T-FlipFlop
Figure 2–7 shows an example of a 4-bit counter.
Figure 2–7. 4-Bit Counter
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Chapter 2: PowerPlay Early Power Estimator Worksheets
Power Estimation Using the PowerPlay Early Power Estimator
2–9
User Flash Memory Section
When your design uses the UFM, the PowerPlay EPE spreadsheet considers the time
spent during read operations into the power estimation. Figure 2–8 shows the UFM
section in the PowerPlay EPE spreadsheet.
Figure 2–8. UFM Section in PowerPlay EPE Spreadsheet
Table 2–8 lists the parameters in the UFM section of the PowerPlay EPE spreadsheet.
Table 2–8. UFM Section Information
Column Heading
Description
UFM Module
Specify a name for the UFM module in this column. This is an optional value.
Read %
Enter the percentage of time the UFM spends in Read mode. It takes 16 clock cycles to shift the
serial data out after an internal UFM read so the read operation occurs less than
1/17 (or about 6%) of the time. The clock in this calculation is the UFM block’s DRCLK signal.
Total Power (mW)
Total power dissipation due to reading from the UFM block (mW). Programming and erasing
can only be performed for a limited number of times over the life of the device so they do not
contribute to average power.
User Comments
Enter any comments. This is an optional value.
I/O Worksheet
MAX II and MAX V devices feature programmable I/O pins that support a wide
range of industry I/O standards for increased design flexibility. The I/O section in the
PowerPlay EPE spreadsheet allows you to estimate the I/O pin power consumption
based on the pin’s I/O standards.
The total thermal power is the sum of the thermal power consumed by the device
from each power rail, as shown in Equation 2–2:
Equation 2–2.
Thermal Power = Thermal PINT + Thermal PIO
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Figure 2–9 shows a graphical representation of the thermal power consumption.
Figure 2–9. Thermal Power Representation
VCCINT
VCCIO
ICCINT
ICCIO
MAX V Device
Thermal PINT
Thermal PIO
If you specify the I/O bank for the I/O pins in the I/O section, the PowerPlay EPE
spreadsheet estimates the current for each I/O bank based on the VCCIO settings.
Figure 2–10 shows the I/O bank parameter settings.
Figure 2–10. I/O Bank Parameter Setting
Table 2–9 lists the I/O bank parameters in the I/O worksheet of the PowerPlay EPE
spreadsheet, as shown in Figure 2–10.
Table 2–9. I/O Bank Section Information
Column Heading
Description
VCCIO
Select the VCCIO voltage for each bank. Use this to cross-check the selected I/O standards in the
I/O section for warning purposes.
ICCIO
Shows the total supply current due to the I/O pins in each I/O bank.
Unassigned
Represents the ICCIO of all the I/O modules not assigned to an I/O bank.
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Power Estimation Using the PowerPlay Early Power Estimator
2–11
Each row in the I/O module represents a design module where the I/O pins have the
same frequency, toggle percentage, average capacitive load, I/O standard, and I/O
bank. Figure 2–11 shows the I/O module of the PowerPlay EPE spreadsheet.
Figure 2–11. I/O Module Setting
Table 2–10 lists the I/O module parameters in the I/O worksheet of the PowerPlay
EPE spreadsheet.
Table 2–10. I/O Module Section Information (Part 1 of 2)
Column Heading
Description
Module
Specify a name for the module in this column. This is an optional value.
I/O Standard
Select the I/O standard for the input, output, or bidirectional pins in this module from the
pull-down list. The calculated I/O power varies based on the I/O standard.
Clock Freq (MHz)
Enter the clock frequency (in MHz). This value is limited by the maximum frequency
specification for the device families.
A 100 MHz input clock with a 12.5% toggle means that each I/O pin toggles 12.5 million times
per second (100 × 12.5%).
# Output Pins
Enter the number of output pins in this module.
# Input Pins
Enter the number of input pins in this module.
Enter the number of bidirectional pins in this module.
# Bidir Pins
I/O Bank
An I/O pin configured as bidirectional but is used only as an output pin consumes more power
than an I/O configured as an output-only pin due to the toggling of the input buffer every time
the output buffer toggles as they share a common pin.
Select the I/O bank for the module. If you do not know which I/O bank the pins will be assigned
to, leave the value as “?”. Assigning the I/O module to a bank ensures whether your I/O voltage
assignments are compatible or not, allowing per bank ICCIO reporting.
The PowerPlay EPE spreadsheet does not take any I/O placement constraints into
consideration except for the I/O standard and bank match and the I/O voltage.
Toggle %
Enter the average percentage of input, output, and bidirectional pins toggling on each clock
cycle. For input pins used as clocks, the toggle percentage ranges from 0 to 200% because
clocks toggle at twice the frequency.
Typically, the toggle percentage is 12.5%. To be more conservative, you can use a higher toggle
percentage.
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Table 2–10. I/O Module Section Information (Part 2 of 2)
Column Heading
Description
Enter the average percentage of time that the:
OE %
■
output I/O pins are enabled.
■
bidirectional I/O pins are outputs and enabled.
During the remaining time the:
■
output I/O pins are tri-stated.
■
bidirectional I/O pins are inputs.
The value you enter must be a percentage between 0 and 100%.
Enter the pin loading external to the chip (in pF).
Load (pF)
This only applies to outputs and bidirectional pins. Pin and package capacitance is already
included in the I/O model. Therefore, only include the off-chip capacitance in the Load
parameter.
Bank I/O Std Check
Indicates whether the selected I/O standard is available on the selected I/O bank or not. Not all
I/O banks support every I/O standard.
Bank Voltage Check
Indicates whether the selected I/O bank has a voltage compatible with the selected I/O standard
or not.
This shows the power dissipation due to estimated routing.
Routing
Routing power depends on placement-and-routing information, which is a function of your
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 Power
Analyzer.
This shows the power dissipation due to internal and load toggling of the I/O.
Block
For accurate analysis based on your design’s I/O configuration, use the Quartus II PowerPlay
Power Analyzer.
Total
This shows the total power dissipation. The total power dissipation is the sum of the routing
and block power.
ICCINT
This shows the current drawn from the ICCINT power rail and powers the internal digital circuitry
and routing.
ICCIO
This shows the current drawn from this bank’s VCCIO power rail.
User Comment
Enter any comments. This is an optional value.
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Chapter 2: PowerPlay Early Power Estimator Worksheets
Factors Affecting the PowerPlay Early Power Estimator Spreadsheet Accuracy
2–13
Factors Affecting the PowerPlay Early Power Estimator Spreadsheet
Accuracy
There are many factors that affect the estimated values displayed in the PowerPlay
EPE spreadsheet. In particular, the input parameters entered concerning toggle rates,
airflow, and temperature must be accurate to ensure that the system is modeled
correctly in the PowerPlay EPE spreadsheet.
Toggle Rate
The toggle rates specified in the PowerPlay EPE spreadsheet can have a large impact
on the dynamic power consumption displayed. To obtain an accurate estimate, you
must input toggle rates that are realistic. Determining realistic toggle rates requires
you to know what kind of input the CPLD is receiving and how often it toggles.
To get an accurate estimate even if the design is not complete, isolate the separate
modules in the design by functionality and estimate the resource usage along with the
toggle rates of the resources. The easiest way to accomplish this is to leverage
previous designs to estimate the toggle rates for modules with similar functionality.
The input data in Figure 2–12 is encoded for data transmission and has a roughly 50%
toggle rate.
Figure 2–12. Decoder and Encoder Block Diagram
Mod Input
Data
Decoder
RAM
Filter
Modulator
Encoder
In this case, you must estimate the following:
■
Data toggle rate
■
Mod input toggle rate
■
Resource estimate for the Decoder module, RAM, Filter, Modulator, and Encoder
■
Toggle rate for the Decoder module, RAM, Filter, Modulator, and Encoder
You can generate these estimates in many ways. If you used similar modules in the
past with data inputs of roughly the same toggle rate, you can leverage that
information. If there are MATLAB simulations available for some blocks, you can
obtain the toggle rate information. If the HDL is available for some of the modules,
you can simulate them.
If the HDL is complete, the best way to determine toggle rate is to simulate the design.
The accuracy of toggle rate estimates depends on the accuracy of the input vectors.
Therefore, determining whether or not the simulation coverage is high gives you a
good estimate of how accurate the toggle rate information is.
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Chapter 2: PowerPlay Early Power Estimator Worksheets
Factors Affecting the PowerPlay Early Power Estimator Spreadsheet Accuracy
The Quartus II software can determine toggle rates of each resource used in the
design if you provide information from simulation tools. Designs can be simulated in
many different tools and the information provided to the Quartus II software through
a Signal Activity File (.saf). The Quartus II PowerPlay Power Analyzer provides the
most accurate power estimate. You can import the Comma-Separated Value File (.csv)
from the Quartus II software into the PowerPlay EPE spreadsheet for estimating
power after the design is complete.
Airflow
The PowerPlay EPE spreadsheet allows you to specify the airflow present at the
device. This value affects thermal analysis and can significantly affect the power
consumed by the device. To obtain an accurate estimate, you must correctly determine
the airflow at the CPLD, not the output of the fan providing the airflow.
It is often difficult to place the device adjacent to the fan providing the airflow. The
path of the airflow is likely to traverse a length on the board before reaching the
device, thus diminishing the actual airflow the device receives. Figure 2–13 shows a
fan that is placed at the end of the board. The airflow at the CPLD is weaker than it is
at the fan.
Figure 2–13. Airflow and CPLD Position
F
A
N
CPLD
It is also necessary to take into consideration the blocked airflow. Figure 2–14 shows a
device blocking the airflow from the CPLD, significantly reducing the airflow seen at
the CPLD. The airflow from the fan also has to cool board components and other
devices before reaching the CPLD.
Figure 2–14. Airflow with Component and CPLD Positions
F
A
N
Device
CPLD
The considerations above can heavily influence the airflow received at the device.
When entering information into the PowerPlay EPE spreadsheet, you have to
consider these implications in order to get an accurate airflow value at the CPLD.
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Factors Affecting the PowerPlay Early Power Estimator Spreadsheet Accuracy
2–15
Temperature
To calculate the thermal information of the device correctly, you are required to enter
the ambient air temperature for the device in the PowerPlay EPE spreadsheet.
Ambient temperature refers to the temperature of the air around the device. This is
usually higher than the ambient temperature outside of the system. To get an accurate
representation of ambient temperature for the device, you must measure the
temperature as close to the device as possible with a thermocouple device.
Entering the incorrect ambient air temperature can drastically alter the power
estimates in the PowerPlay EPE spreadsheet. Figure 2–15 shows a simple system with
the CPLD housed in a box. In this case, the temperature is very different at each of the
numbered locations.
Figure 2–15. Temperature Variances
4
2
F
A
N
3
CPLD
1
For example, location 3 is where the ambient temperature pertaining to the device
should be obtained for input into the PowerPlay EPE spreadsheet. Locations 1 and 2
are cooler than location 3 and location 4 and is likely close to 25 °C if the ambient
temperature outside the box is 25 °C. Temperatures close to devices in a system are
often in the neighborhood of 50–60 °C but the values can vary significantly. In order
to obtain accurate power estimates from the PowerPlay EPE spreadsheet, it is very
important to get a realistic estimate of the ambient temperature near the CPLD device.
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3. Power Saving Techniques
This chapter describes ways to reduce power cosumption.
The following guidelines reduce power consumption for an application:
■
Slow the operation in portions of the circuit. ICC is proportional to the frequency of
the operation. Slowing parts of a circuit lowers the ICC; therefore, reduces the
power. MAX II and MAX V devices provide global or array clock source for all
registers. Signals that do not require high-speed operation can use a slower array
clock that reduces the system power consumption.
■
Reduce the number of outputs. Standby and dynamic current are required to
support all the I/O pins on the device. Reducing the number of I/O pins can
reduce current necessary for the device thus reduces the power.
■
Reduce the loading and external capacitance on the outputs. Excessive loading
and capacitance of the PCB traces and other ICs on the output pins significantly
increases power. Keeping the excess load and external capacitance to a minimum
on the output pins whenever possible significantly reduces the current necessary
for the device.
■
Reduce the amount of circuitry in the device. Power depends on the amount of
internal logic that switches at any given time. Reducing the amount of logic in a
device reduces the current in the device and thus reduces the power.
■
Modify the design to reduce power. Identify areas in the design that you can revise
to reduce the power requirements. Common solutions include reducing the
number of switching nodes and required logic and removing any redundant or
unnecessary signals.
■
Modify the I/O Locations. Grouping the I/O pins from common logic blocks
allows the Quartus II software to place the associated logic closer together. The
more compact a logic block and I/O, the lower its dynamic power (this is
especially true of low utilization designs with the I/O spread around the device).
■
Increase the performance requirements in the constraint file. Improving the
performance that is beyond the need for operation reduces the power dissipation.
The Quartus II software optimizes the design and places logic closer together, uses
shorter routing and fewer logic levels, and lowers dynamic power and improves
performance.
f MAX II and MAX V devices offer a power-down capability that conserves battery life
for portable applications. For more information about the power-down capability in
MAX II devices and an application design example, refer to AN 422: Power
Management in Portable Systems Using MAX II CPLDs.
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Additional Information
This chapter provides additional information about this user guide and Altera.
Document Revision History
The following table lists the revision history for this user guide.
Date
Version
December 2010
Changes
1.0
Initial release.
How to Contact Altera
To locate the most up-to-date information about Altera® products, refer to the
following table.
Contact (1)
Technical support
Technical training
Product literature
Contact Method
Address
Website
www.altera.com/support
Website
www.altera.com/training
Email
custrain@altera.com
Website
www.altera.com/literature
Non-technical support (General)
Email
nacomp@altera.com
(Software Licensing)
Email
authorization@altera.com
Note:
(1) You can also contact your local Altera sales office or sales representative.
Typographic Conventions
The following table lists the typographic conventions this user guide uses.
Visual Cue
Meaning
Bold Type with Initial Capital
Letters
Indicate command names, dialog box titles, dialog box options, and other GUI
labels. For example, Save As dialog box. For GUI elements, capitalization matches
the GUI.
bold type
Indicates directory names, project names, disk drive names, file names, file name
extensions, software utility names, and GUI labels. For example, \qdesigns
directory, D: drive, and chiptrip.gdf file.
Italic Type with Initial Capital Letters
Indicate document titles. For example, Stratix IV Design Guidelines.
Indicates variables. For example, n + 1.
italic type
Variable names are enclosed in angle brackets (< >). For example, <file name> and
<project name>.pof file.
Initial Capital Letters
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Indicate keyboard keys and menu names. For example, the Delete key and the
Options menu.
PowerPlay Early Power Estimator for Altera CPLDs User Guide
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Additional Information
Typographic Conventions
Visual Cue
“Subheading Title”
Meaning
Quotation marks indicate references to sections within a document and titles of
Quartus II Help topics. For example, “Typographic Conventions.”
Indicates signal, port, register, bit, block, and primitive names. For example, data1,
tdi, and input. The suffix n denotes an active-low signal. For example, resetn.
Courier type
Indicates command line commands and anything that must be typed exactly as it
appears. For example, c:\qdesigns\tutorial\chiptrip.gdf.
Also indicates sections of an actual file, such as a Report File, references to parts of
files (for example, the AHDL keyword SUBDESIGN), and logic function names (for
example, TRI).
r
An angled arrow instructs you to press the Enter key.
1., 2., 3., and
a., b., c., and so on
Numbered steps indicate a list of items when the sequence of the items is important,
such as the steps listed in a procedure.
■ ■ ■
Bullets indicate a list of items when the sequence of the items is not important.
1
The hand points to information that requires special attention.
A question mark directs you to a software help system with related information.
f
The feet direct you to another document or website with related information.
c
A caution calls attention to a condition or possible situation that can damage or
destroy the product or your work.
w
A warning calls attention to a condition or possible situation that can cause you
injury.
The envelope links to the Email Subscription Management Center page of the Altera
website, where you can sign up to receive update notifications for Altera documents.
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