Clock Gating Network Layout for Lower Latency Clock Distribution

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Solution Overview

Problem

Conventional clock circuits in digital integrated circuits suffer from excessive clock latency and high power consumption due to long clock signal propagation paths and uneven path lengths, which affect clock signal transmission and quality.

Innovation Solution

A clock circuit design featuring a buffer module and N clock gating cells with a tree-shaped H-shaped clock network structure, where the clock signal travels through only one level of clock gating cells, reducing latency and power consumption by ensuring equal path lengths and using integrated clock gating cells to enhance clock signal quality and duty ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a conventional clock circuit structure is used, then the clock circuit can operate, but the propagation path of the clock signal becomes excessively long, resulting in relatively long clock latency and high power consumption

Engineering Contradiction:
Improveclock latencyVSAvoidclock path structure
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The clock circuit is divided into multiple independent clock domains, each with its own clock gating cell. The clock signal is segmented into different paths (first clock path and second clock path) that can be independently controlled, reducing the overall propagation latency in each segment while maintaining full coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension of control by adding clock gating cells that can selectively enable or disable clock signals in different paths. This dimensional addition allows the circuit to optimize clock distribution by activating only necessary paths, thereby reducing effective propagation distance and power consumption without compromising functionality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Use of energy by stationary object

If a conventional clock circuit structure is used, then the clock circuit can operate, but the power consumption on each clock path becomes excessively high

Engineering Contradiction:
Improvepower consumptionVSAvoidclock path structure
Core Design Contradiction:
Use of energy by stationary objectVSDevice complexity

Solution Approach 1:

The clock gating cells provide dynamic control over clock signal distribution. Based on operational requirements, the circuit can enable or disable specific clock paths, making the power consumption adaptive rather than static. This dynamic control allows the system to consume only the necessary power for active functional units.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Different clock paths are optimized independently with local clock gating control. Each clock domain can have its own gating strategy tailored to its specific requirements, allowing power-efficient operation in inactive regions while maintaining full performance in active regions.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If frequency division is performed by subtracting clock pulses, then the output clock frequency can be divided, but the clock path becomes longer and latency increases

Engineering Contradiction:
Improvefrequency division ratioVSAvoidclock latency
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent introduces clock gating cells as intermediary components between the clock source and functional units. These gating cells provide frequency division and selection functionality without requiring long subtraction-based pulse counting paths. The intermediary gating mechanism achieves frequency control with minimal propagation delay.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Loss of time

If the clock signal propagation path is shortened, then clock latency is reduced, but the driving capability of the clock signal may be insufficient

Engineering Contradiction:
Improveclock latencyVSAvoiddriving capability
Core Design Contradiction:
Loss of timeVSPower

Solution Approach 1:

The patent combines multiple functions into the clock gating cell: frequency division, path selection, and signal buffering. By merging these functions into a single integrated cell, the design achieves short propagation paths while maintaining sufficient driving capability through the combined effect of multiple functional elements within the gating cell.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3197055B1Clock circuit and clock signal transmission method thereof
Publication Date: 2020.03.11 HUAWEI TECH CO LTD
  • EP3197055B1 patent drawingFigure 1~2
  • EP3197055B1 patent drawingFigure 3~5
  • EP3197055B1 patent drawingFigure 6

AI summary

The present invention provides a clock circuit and a clock signal transmission method. The clock circuit includes a buffer module (110), N multiplexers (120), and N clock gating cells (130). The buffer module (110) includes an input end (111) and N output ends (112), and is configured to enhance a driving capability of a clock signal received by the input end, and output the clock signal whose driving capability is enhanced from the N output ends, and the N output ends are connected to data ends of the N clock gating cells one to one. Output ends of the N first multiplexers are connected to enabling ends (131) of the N clock gating cells one to one. Each clock gating cell (130) is configured to output a clock signal from an output end (133) according to a frequency division logic signal or a gating logic signal received by an enabling end from an output end of a corresponding multiplexer and the clock signal received by a data end from an output end of the buffer module. According to the technical solutions of the present invention, a clock path can be shortened, a transmission latency of a clock source signal can be reduced, and power consumption of a clock circuit can be reduced.