Memory Element Overdrive Voltage Routing for Critical Path Timing

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Solution Overview

Problem

Integrated circuits face challenges in balancing reliability and performance due to difficulties in applying overdrive voltages that are sufficient for pass gate performance without overstressing gate oxides, leading to issues with signal delays and data path integrity.

Innovation Solution

The implementation of adjustable power supply circuitry that allows for varying overdrive voltages to be applied to different circuit blocks based on their criticality, with a logic design system determining optimal voltage levels to balance reliability, performance, and power consumption targets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high overdrive voltages are applied to pass gates to improve performance, then pass gate performance is improved, but gate oxide reliability deteriorates

Engineering Contradiction:

Improvepass gate performanceVSAvoidgate oxide reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies different overdrive voltage levels to different circuit blocks based on their specific performance requirements. Critical path blocks receive higher overdrive voltages (e.g., 1.3V) to ensure fast operation, while non-critical blocks use lower overdrive voltages (e.g., 1.15V) to preserve gate oxide reliability. This localized differentiation resolves the contradiction by applying stress only where necessary for performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements dynamically adjustable overdrive voltage levels that can be configured based on operating conditions and performance requirements. The ability to adjust voltage levels allows the system to optimize between performance and reliability depending on the specific application needs, rather than using a fixed high or low voltage approach.

Inventive Principle:

Principle #15Dynamics

2Loss of time

If high overdrive voltages are applied to critical paths to meet timing requirements, then timing performance is improved, but power consumption increases

Engineering Contradiction:

Improvesignal delayVSAvoidpower consumption

Core Design Contradiction:

Loss of timeVSUse of energy by moving object

Solution Approach 1:

The patent applies high overdrive voltages only to specific critical path blocks where timing is constrained, while using lower voltages in non-critical areas. This localized approach ensures that power consumption is increased only where necessary to meet timing requirements, rather than across the entire circuit.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the circuit into different blocks with different overdrive voltage requirements. By dividing the circuit and applying appropriate voltage levels to each segment based on its timing criticality, the system achieves necessary performance while minimizing overall power consumption.

Inventive Principle:

Principle #1Segmentation

3Reliability

If low overdrive voltages are used to preserve gate oxide reliability, then reliability is improved, but pass gate performance deteriorates

Engineering Contradiction:

Improvegate oxide reliabilityVSAvoidpass gate performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent uses low overdrive voltages in non-critical circuit blocks to preserve gate oxide reliability, while applying high overdrive voltages only to critical path blocks where performance is essential. This selective approach maintains reliability across the majority of the circuit while ensuring critical functions meet timing requirements.

Inventive Principle:

Principle #3Local quality

4Productivity

If uniform high overdrive voltage is applied to all circuit blocks, then performance is improved, but device complexity increases

Engineering Contradiction:

Improvecircuit performanceVSAvoidpower supply circuitry complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the power supply circuitry into multiple independent voltage domains, each capable of operating at different overdrive voltage levels. This segmentation allows different circuit blocks to receive appropriate voltage levels without requiring a completely uniform high-voltage approach, thereby managing complexity while maintaining performance.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8502558B1Computer-aided design tools and memory element power supply circuitry for selectively overdriving circuit blocks

Publication Date: 2013.08.06 ALTERA CORP

AI summary

Integrated circuits are provided with circuitry such as multiplexers that can be selectively configured to route different adjustable power supply voltages to different circuit blocks on the integrated circuits. The circuit blocks may contain memory elements that are powered by the power supply voltages and that provide corresponding static output control signals at magnitudes that are determined by the power supply voltages. The control signals from the memory elements may be applied to the gates of transistors in the circuit blocks. Logic on an integrated circuit may be powered at a given power supply voltage level. The memory elements may provide their output signals at overdrive voltage levels that are elevated with respect to the given power supply voltage level. Memory elements associated with circuit blocks that contain critical paths can be overdriven at voltages that are larger than memory elements associated with circuit blocks that contain noncritical paths.