Self-Calibrated IC Voltage Control for Low-Power Correct Operation

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Solution Overview

Problem

As integrated circuits with increasing transistors and operating frequencies face challenges in managing power consumption, reducing supply voltage to conserve power can lead to incorrect operation, and existing methods struggle to balance power management with performance and thermal requirements, especially in battery-powered devices.

Innovation Solution

An integrated circuit with a self-calibration unit and local power manager that iteratively tests supply voltage levels to determine the lowest voltage for correct operation, using a measurement unit to adjust the supply voltage based on propagation delay measurements, allowing for dynamic voltage and frequency management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If supply voltage is reduced to manage power consumption, then power consumption decreases, but operation correctness deteriorates

Engineering Contradiction:
Improvepower consumptionVSAvoidoperation correctness
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements dynamic voltage adjustment by allowing the supply voltage to vary over time and across different circuit instances. Instead of using a static voltage specification, the system dynamically determines and adjusts the supply voltage based on actual operating conditions, enabling the circuit to operate at the lowest possible voltage that maintains correctness for each specific instance and workload.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs self-calibration units embedded within each integrated circuit instance that automatically characterize the circuit's own behavior and determine its specific voltage-frequency characteristics. This self-service approach eliminates the need for conservative worst-case specifications by allowing each circuit to self-determine its optimal operating parameters, thereby enabling lower voltage operation while maintaining reliability.

Inventive Principle:
Principle #25Self-service

2Use of energy by moving object

If supply voltage is reduced to manage power consumption, then power consumption decreases, but performance deteriorates

Engineering Contradiction:
Improvepower consumptionVSAvoidperformance
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The system dynamically adjusts supply voltage based on actual performance requirements and workload conditions. By continuously monitoring and adapting the voltage level to match the minimum needed for correct operation, the system avoids the performance penalty associated with static conservative voltage specifications while maintaining acceptable performance through instance-specific optimization.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operating voltage parameter based on measured propagation delays and circuit characteristics. By adjusting the voltage parameter to the minimum level that maintains correct operation for each specific circuit instance, the system achieves lower power consumption without significant performance loss, as each instance operates at its optimal voltage point rather than a conservative worst-case value.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If static supply voltage specification is used to ensure correct operation across all variations, then reliability is maintained, but power consumption increases

Engineering Contradiction:
Improveoperation correctnessVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

Each integrated circuit instance performs self-calibration to characterize its own behavior and determine its specific voltage-frequency characteristics. This self-service approach replaces conservative static specifications with instance-specific dynamic determination, allowing each circuit to operate at the lowest voltage that ensures correctness for its particular manufacturing variations and operating conditions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the supply voltage parameter from a fixed static specification to a dynamic instance-specific value. By measuring actual propagation delays and circuit behavior, the system determines the minimum voltage required for correct operation in each specific instance, thereby reducing power consumption while maintaining reliability through parameter adaptation rather than conservative fixed specifications.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If self-calibration and iterative testing are performed to determine optimal voltage, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improvevoltage characterization accuracyVSAvoidcalibration circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the voltage characterization function into separate self-calibration units embedded in each integrated circuit instance. This segmentation allows each instance to independently characterize its own behavior without requiring complex external testing equipment or centralized control, achieving high measurement precision through distributed self-measurement while keeping individual unit complexity manageable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The self-calibration units perform automatic characterization of their own circuit behavior through iterative testing and measurement. This self-service approach achieves high measurement precision by having each circuit measure its own propagation delays and voltage characteristics without external intervention, thereby obtaining accurate instance-specific data while avoiding the complexity of external characterization systems.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2391931B1Dynamic voltage and frequency management
Publication Date: 2017.11.01 APPLE INC
  • EP2391931B1 patent drawingFigure 1
  • EP2391931B1 patent drawingFigure 2
  • EP2391931B1 patent drawingFigure 3

AI summary

In one embodiment, an integrated circuit includes a self calibration unit configured to iterate a test on a logic circuit in the integrated circuit at respectively lower supply voltage magnitudes until the test fails. A lowest supply voltage magnitude at which the test passes is used to generate a requested supply voltage magnitude for the integrated circuit. In an embodiment, an integrated circuit includes a series connection of logic gates physically distributed over an area of the integrated circuit, and a measurement unit configured to launch a logical transition into the series and detect a corresponding transition at the output of the series. The amount of time between the launch and the detection is used to request a supply voltage magnitude for the integrated circuit.