Clock Divider Synchronization Using Slip Cycles for Sub-Rate Clocks

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Solution Overview

Problem

Modern electronic devices face challenges in synchronizing multiple sub-rate clocks, which are essential for high-speed data communication and processing, as they often experience clock signal spacing errors, leading to inefficiencies in timing reference alignment.

Innovation Solution

A system and method are provided that utilize a circuit with a buffer delay gate and flip-flops to compare and synchronize multiple output clock signals, generating a slip signal to align follower clocks with a master clock, ensuring precise timing across multiple frequency dividers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple frequency dividers are used to generate sub-rate clocks, then data processing capability is improved, but clock synchronization accuracy deteriorates due to spacing errors

Engineering Contradiction:
Improvedata processing capabilityVSAvoidclock synchronization accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the first output clock signal is continuously compared with the second output clock signal. When desynchronization is detected (spacing errors exceed a threshold), a slip signal is generated and applied to the second frequency divider to correct the timing. This closed-loop feedback system maintains clock synchronization accuracy while allowing multiple frequency dividers to operate simultaneously for enhanced data processing capability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces a slip signal as an intermediary control mechanism between the clock comparison logic and the second frequency divider. This slip signal acts as a mediator that adjusts the timing of the second output clock signal without directly modifying the frequency divider's core operation, thereby resolving the synchronization error while preserving the data processing functionality of multiple dividers.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If clock frequency is increased for high-speed communication, then data transfer rate is improved, but timing reference alignment deteriorates due to spacing errors

Engineering Contradiction:
Improvedata transfer rateVSAvoidtiming reference alignment
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent employs continuous feedback comparison between the first output clock signal (master) and the second output clock signal (follower). When timing reference misalignment is detected at high speeds, the system generates a slip signal to correct the second frequency divider's output. This feedback mechanism ensures timing reference alignment is maintained even when operating at high data transfer rates with multiple frequency dividers.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If multiple clock domains with different frequencies are used, then functionality and operation modes are improved, but clock synchronization complexity increases

Engineering Contradiction:
Improvefunctionality and operation modesVSAvoidclock synchronization complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by implementing synchronization only where needed - specifically between the first and second output clock signals that require coordination. The slip signal mechanism is localized to the second frequency divider's control input, allowing it to be adjusted independently without affecting other clock domains. This localized approach maintains adaptability across multiple clock domains while minimizing overall synchronization complexity.

Inventive Principle:
Principle #3Local quality

4Ease of manufacture

If traditional synchronization methods are used, then implementation simplicity is maintained, but power consumption increases due to continuous adjustment

Engineering Contradiction:
Improveimplementation simplicityVSAvoidpower consumption
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action by applying the slip signal only when desynchronization is detected, rather than continuously adjusting the clock signals. The comparison circuit periodically monitors the timing alignment between the first and second output clock signals, and the slip signal is generated only during correction periods when spacing errors exceed the threshold. This periodic correction approach reduces power consumption compared to continuous adjustment methods while maintaining implementation simplicity through the straightforward comparison-and-correct logic.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP4455828A1Synchronization of multiple clock dividers by using lower-frequency clocks and slipping cycles
Publication Date: 2024.10.30 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • EP4455828A1 patent drawingFigure 1A
  • EP4455828A1 patent drawingFigure 1B
  • EP4455828A1 patent drawingFigure 1C

AI summary

Systems and methods for synchronizing multiple of output clocks. The system includes: a plurality of frequency dividers configured to receive a plurality of input clock signals and produce a plurality of output clock signals, wherein each of the plurality of output clock signals are lower in frequency than a corresponding input clock signal; and a circuit. The circuit is configured to: compare a first output clock signal of the plurality of output clock signals to a second output clock signal of the plurality of output clock signals to determine whether the first output clock signal is synchronized with the second output clock signal, generate a slip signal in response to determining that the first output clock signal is not synchronized with the second output clock signal, and apply the slip signal to the second output clock signal to synchronize the second output clock signal with the first output clock signal.