Voltage-Frequency Control Trajectory Optimization

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Solution Overview

Problem

Existing voltage-frequency control methods in electronic circuits, such as those used in System-on-Chip (SoC) and Globally Asynchronous and Locally Synchronous (GALS) architectures, face inefficiencies during transitions between operating points, leading to suboptimal dynamic consumption and potential timing faults.

Innovation Solution

A method that jointly controls the evolution of supply voltage and frequency by following a reference curve within the operating range, maximizing performance while minimizing consumption, using a coupling of generic voltage and frequency actuators, and implementing Proportional-Integral-Derivative (PID) corrections to maintain optimal operating points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If voltage and frequency are changed sequentially to avoid timing faults, then timing reliability is improved, but dynamic energy consumption increases due to suboptimal transition trajectories

Engineering Contradiction:
Improvetiming reliabilityVSAvoiddynamic energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by pre-calculating the optimal transition trajectory in the voltage-frequency plane before executing the transition. The reference curve is determined in advance based on the starting and target operating points, allowing the system to plan the entire transition path beforehand. This ensures that each intermediate point on the trajectory satisfies timing constraints while minimizing energy consumption, resolving the contradiction between reliability and energy efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by transitioning from static sequential voltage-frequency changes to dynamic joint control along a continuous reference curve. The system continuously adjusts both voltage and frequency parameters simultaneously according to the pre-calculated optimal trajectory, adapting to timing constraints at each point along the path. This dynamic approach allows the system to maintain timing reliability while following an energy-optimal transition path.

Inventive Principle:
Principle #15Dynamics

2Use of energy by moving object

If voltage and frequency are jointly controlled along a reference curve, then energy efficiency is improved, but control complexity increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidcontrol complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the complex joint control problem into two distinct phases: (1) offline pre-calculation of the reference curve based on timing constraints and operating points, and (2) online tracking of the pre-calculated curve. This segmentation separates the computationally intensive optimization task from the real-time control task, reducing online control complexity while maintaining energy efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses preliminary action by pre-calculating and storing the optimal reference curve before runtime. The complex optimization computations are performed offline to generate the voltage-frequency trajectory, which is then stored and simply tracked during operation. This eliminates the need for real-time optimization calculations, significantly reducing control complexity while preserving energy efficiency benefits.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If transition trajectory is optimized in voltage-frequency plane, then performance is maximized with minimal consumption, but risk of timing faults increases during transient phases

Engineering Contradiction:
ImproveperformanceVSAvoidtiming fault prevention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements feedback by continuously monitoring the actual operating point during transitions and comparing it with the reference curve. The system uses this feedback information to adjust control signals and ensure the trajectory is followed accurately. This feedback mechanism guarantees that timing constraints are satisfied at each point along the optimized path, preventing timing faults while maintaining performance benefits.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies preliminary action by pre-validating the reference curve to ensure all points satisfy timing constraints before execution. The offline optimization process generates a trajectory that is guaranteed to meet timing requirements, and the online phase simply follows this validated path. This preliminary validation ensures timing fault prevention while allowing the system to operate at optimal performance points.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2795426B1Optimised voltage-frequency control
Publication Date: 2020.10.21 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2795426B1 patent drawingFigure 1~3
  • EP2795426B1 patent drawingFigure 4~6
  • EP2795426B1 patent drawingFigure 7~9

AI summary

A method for controlling an electronic circuit, characterised in that it comprises a step of feedback control of a current voltage-frequency operating point relative to a reference curve of a voltage-frequency domain of operation associated with the circuit, to bring the circuit from a first operating point to a second operating point, said reference curve linking said first and second operating points in an optimal trajectory relative to a boundary of said domain.