Data-Gated Flip-Flop Clock Gating for Low Power and Setup Time

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Solution Overview

Problem

Existing clock-gating cells in integrated circuits face challenges in minimizing power consumption and setup time while maintaining low area usage, as they often require additional logic that increases area and power overhead, and fail to efficiently gate the clock signal based on data activity.

Innovation Solution

A data-gated flip-flop design incorporating an exclusive OR component and a clock gating circuit that generates a clock gating signal to gate the clock only when data input differs from the output, reducing unnecessary clock switching and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If traditional clock-gating cells are used to reduce power consumption, then power usage is reduced, but area usage and setup time increase due to additional logic requirements

Engineering Contradiction:
Improvepower consumptionVSAvoidarea usage
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent combines the clock-gating functionality with the flip-flop structure itself, merging the clock gate logic into the flip-flop's internal logic paths. This integration eliminates the need for separate clock-gating cells, thereby reducing area usage while maintaining power-saving functionality. The clock signal is gated directly at the flip-flop inputs through shared logic resources.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The flip-flop structure is designed to perform multiple functions: data storage, clock gating, and setup time optimization. By making the flip-flop universal and multi-functional, the patent eliminates the need for dedicated clock-gating cells, reducing overall area usage while achieving power consumption reduction through selective clock gating based on data activity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Use of energy by moving object

If traditional clock-gating cells are used to reduce power consumption, then power usage is reduced, but setup time increases due to additional logic

Engineering Contradiction:
Improvepower consumptionVSAvoidsetup time
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The clock-gating logic is merged with the flip-flop's data input logic paths. By combining these functions, the patent reduces the total logic depth that the data signal must traverse before being captured by the flip-flop, thereby reducing setup time while maintaining the power-saving benefits of selective clock gating.

Inventive Principle:
Principle #5Merging (Combining)

3Loss of energy

If clock gating is implemented to reduce power consumption, then power savings are achieved, but the circuit requires additional logic that increases area

Engineering Contradiction:
Improvepower savingsVSAvoidcircuit area
Core Design Contradiction:
Loss of energyVSArea of stationary object

Solution Approach 1:

The patent merges clock-gating logic with existing flip-flop logic resources, eliminating the need for separate clock-gating cells. This integration achieves power savings through selective clock gating while minimizing area overhead by reusing existing logic structures within the flip-flop.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The flip-flop is designed as a universal element that performs both data storage and clock gating functions. This multi-functionality reduces the need for additional dedicated clock-gating logic, thereby minimizing area overhead while achieving significant power savings through intelligent clock gating based on data activity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Loss of energy

If clock gating is implemented to reduce power consumption, then power savings are achieved, but the circuit complexity increases

Engineering Contradiction:
Improvepower savingsVSAvoidcircuit complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent combines clock-gating functionality with the flip-flop's internal logic, merging multiple functions into a unified structure. This integration reduces overall circuit complexity by eliminating separate clock-gating cells and their associated control logic, while maintaining power-saving benefits through selective clock gating.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3465911B1Low clock power data-gated FLIP-flop
Publication Date: 2020.12.23 QUALCOMM INC
  • EP3465911B1 patent drawingFigure 1
  • EP3465911B1 patent drawingFigure 2
  • EP3465911B1 patent drawingFigure 3

AI summary

A low clock power data-gated flip -flop is provided. The data-gated flip-flop includes an exclusive OR component including a first exclusive OR input, a second exclusive OR input, and a first exclusive OR output. The first exclusive OR input is configured to receive a data input to the data-gated flip-flop. The data-gated flip-flop includes a first latch including a first latch data input and a first latch reset input, the first exclusive OR output being coupled to the first latch data input and the first latch reset input. The data-gated flip-flop includes a second latch having a data output, the data output coupled to the second exclusive OR input.