Flip-Flop Enable Strengthening via Stability and Observability Controllers

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Solution Overview

Problem

Integrated circuit designs face high power consumption due to flip-flops (FFs) being enabled unnecessarily, which is undesirable and inefficient, especially in large circuit designs.

Innovation Solution

The method involves determining stability and observability conditions for FFs and using controllers to generate enable signals only when necessary, ensuring that a FF is enabled only when data is being transferred, thereby reducing power consumption by adding STC or ODC controllers to the circuit design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If flip-flops are enabled continuously to ensure data transfer capability, then reliability of data transfer is improved, but power consumption increases

Engineering Contradiction:

Improvedata transfer reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by computing stability conditions (SC) and observability don't-care conditions (ODC) before generating enable signals. The enable signal is strengthened by AND-ing with future SC and past ODC values, ensuring the FF is enabled only when necessary for reliable data transfer while minimizing power consumption.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses feedback by incorporating future stability conditions and past observability conditions into the current enable signal generation. This feedback mechanism ensures that enable signals are generated based on actual data transfer needs, improving reliability while reducing unnecessary power consumption.

Inventive Principle:

Principle #23Feedback

2Use of energy by moving object

If enable signals are strengthened by adding controllers, then power consumption is reduced, but device complexity increases

Engineering Contradiction:

Improvepower consumptionVSAvoidcircuit complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the enable signal generation into separate components: original enable signal, stability condition controller, and observability don't-care controller. Each component handles a specific aspect of the enable logic, making the overall system more manageable and systematic while achieving power reduction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies universality by creating a general methodology that can be applied to any flip-flop in the circuit. The same enable strengthening technique using SC and ODC controllers can be universally applied across different FFs, making the solution scalable and reducing the need for custom designs for each FF.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8984469B2System and method for strengthening of a circuit element to reduce an integrated circuit's power consumption

Publication Date: 2015.03.17 SYNOPSYS INC

AI summary

A system and method enable strengthening of flip-Flops (FFs) in an integrated circuit (IC) for the purpose of reducing power consumption. This is achieved by using stability condition (STC) and observability don't-care (ODC) techniques. Strengthening enable is defined as ensuring that a FF later in the fan-out is enabled only when a FF earlier in the fan-out is driving a signal to that later FF. In an embodiment the fan-in of a FF is traversed and the STC or ODC is determined for the FF. Dependent on the determination a STC controller or an ODC controller is added to control the FF's enable signal. In an embodiment the power savings is checked and a controller is added only if there is a reduction in overall power consumption resulting from the addition of the controller.