Let's Try Agilex™ 3 - Estimation of power consumption

Introduction

Power consumption andthermal design are unavoidable topics in FPGA design, and it is important to estimate power consumption early in the design process to ensure proper power and cooling design.

This article introduces a simple method for estimating power consumption of Agilex™ 3 devices using Altera's Power and Thermal Calculator (PTC ).

Note that we have created a design in advance, assuming that the design is still in process. We will use this design to estimate power consumption and hope it will be helpful for your PTC usage flow (the design is attached at the bottom of this page).
 

Please refer to 
"Types and Calculations of FPGA Power Consumption" and "How to Estimate Altera®FPGA Power Consumption" are also explained in detail in the following contents, which should be read in conjunction with the User Guide. 

- Types of FPGA Power Consumption and How to Calculate
- How to Estimate Altera® FPGA Power Consumption
- Power and Thermal Calculator User Guide

1. What is PTC?

1-1. overview of ptc

The Power and Thermal Calculator (PTC) is a power and thermal design estimation tool for Agilex™ 3/5/7 and Stratix 10. 
It allows you to quickly estimate FPGA power and thermal parameters before, during, and after the design phase. 

1-2. Key Features of PTC

• Can be used early in the design process: Calculate power consumption with resource estimation even if RTL is not yet complete
• Hierarchical analysis: Decompose and visualize power consumption by design hierarchy
• Export/Import data: Useful for team design and reuse
• Intuitive operation with GUI: easy to input resources and check results 
   

1-3. accuracy of ptc and points to note

• PTC results are estimates only. Actual power consumption will vary depending on design details and input signals.
• Detailed analysis with Quartus® Prime Power Analyzer (QPA) is recommended after design is complete.

1-4. access to PTC

PTC is available as a Standalone feature (download and use PTC by itself) or embedded in Quartus® Prime software.

Key point: 
This article describes how PTC works with a full installation of Quartus® Prime software; PTC can be downloaded from the following URL

- Quartus® Prime Pro Edition Design Software Version 25.1.1 for Windows

 

2. example of using PTC

2-1. how to start

Go to the Tools menu in Quartus > Power and Thermal Calculator or enter "quartus_ptc" in the command shell. 
>> 2-2.

2-2. device package selection

After starting PTC, select the device family, package, and speed grade from the pull-down menu. 
We assume that the device is the "Atum A3 Nano " provided by Terasic and select "A3CZ135BB18AE7S". 

The design was created in advance, and a "Flow Summary" is shown below. 
(An archive file of the project is attached at the bottom of this page for your reference.) 

Typical resources for this design are as follows 
- Logic utilization (in ALMs)
- Total RAM Blocks
- Total DSP Blocks

2-3. input resource information

In PTC, for each resource used in the design (Logic, RAM, DSP, Clock, I/O, Transceiver, etc.), the number of resources used, operating frequency, toggle rate, etc. are entered. 
In this flow, we will show you how to generate a .qptc file from a pre-created design and import it into PTC (a case of estimating power consumption during design creation. A sample design is attached at the bottom of the page ).

Tip: Input to 
PTC is done through the GUI. Please refer to the following documents for detailed input methods and various parameters. 
- Power and Thermal Calculator User Guide: 3. Power and Thermal Calculator Graphical User Interface
 

1. Run the Quartus Processing menu > Start > Start Power Analyzer (PA) 
   (must be completed up to Fitter of the design) 
   
    

2. PA will generate a .qptc file in the project folder 
   
    

3. Import .qptc file into PTC 
   File menu > Import Design... > Select "top.qptc 
   

   Note: When opening 
   PTC, be careful not to import a duplicate .qptc file, as the generated .qptc file can be loaded at startup if you are still working in the project folder (resources will be doubled and registered). 
    

4. When the import is complete, the following screen will appear 
   

   Note: When importing 
   , some settings may not be reflected and a Warning message may appear. 
    

5. You can save your settings by clicking File > Save or Save As.... (.ptc format) 
   
    

2-4. Confirmation of Estimation Result

PTC displays the power consumption for each block for the current design. 
For example, if we check the Logic tab, the current Total thermal power (W) is 0.126, but let's check the impact of adding ALM and FF in the future circuit design. 
In this case, we will add a circuit (top_add) with "ALM : 50000, FF : 50000" ( Clock Freq of the design is unified at 200 MHz ). 

[Before edit : 0.126 W]

[after edit: 0.273 W].

We can see that the total thermal power (W) has increased from 0.126 to 0.273 with the addition of the "top_add" circuit. 
As shown above, PTC calculates the power consumption for each resource, allowing you to quickly check the overall power consumption.

Key point: 
Accurate power estimation depends on the accuracy of the input of various types of information (number used, operating frequency, toggle rate). 
For example, the toggle rate requires knowing what inputs the design will receive and how often it will toggle, and if the design is complete, the value is calculated by simulation. If the design is not yet complete, individual modules in the design can be isolated by function, and resource usage and resource toggle rates can be estimated based on historical design assets and other data. 
The following User Guide also provides information on the accuracy of PTC.
- Power and Thermal Calculator User Guide : 5. Factors Affecting the Accuracy of the PTC

Note: 
This example shows how to add circuits to a pre-compiled design, but PTC can easily estimate power without running PA and without RTL. 
The reference procedure is shown below, so please use it according to the phase of your design. 

[PTC startup: before RTL design]

[PTC input: Estimation with about 80% Logic resources]

Summary

• PTC is a powerful tool to be aware of power consumption and thermal design from the early stage of design.
• Hierarchical analysis and data export for efficient team design and reuse
• Realistic toggle ratio and resource utilization settings are important to improve estimation accuracy
• Rough power estimation is possible even before RTL is designed
• Don't forget to perform a detailed analysis with Quartus Prime Power Analyzer (QPA) after design is complete!

Recommended Articles/Documents

• Altera FPGA Development Flow / FPGA Home Page
• FPGA Power Solutions Resources
• Power Distribution Network
• Try it with Agilex™ 3 - Learn FPGA Basics and How to Use Them Immediately
   

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Attached Files

• Agilex3_RAM_DSP_LE_Design_v2511.qar 
  * Please note that for the purpose of this project, only minimum timing constraints are given for estimating power consumption.
  
  As shown below, each resource (shift register / RAM / DSP) can also be adjusted by changing Top's parameters, so please edit and use as needed. 
  

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