Programmable Clock Delay Control for Multi-Domain Skew Locking
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Solution Overview
Problem
In logic devices with multiple clock domains, clock skew issues lead to data loss and faults during data exchange between sub-circuits, as local clock signals may not be synchronized, necessitating effective skew management to ensure proper data exchange.
Innovation Solution
A clock distribution network with a global clock source, programmable delay lines, and a global skew control circuit that adjusts delays to manage clock skew between local clock signals, transitioning between deskewing and locked operating modes based on skew sensor feedback to maintain synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If clock domains are synchronized using fixed delay lines, then device complexity is reduced, but clock skew management capability deteriorates
Solution Approach 1:
The patent implements programmable delay lines that can dynamically adjust their delay values based on detected clock skew conditions. The delay lines transition between different operating modes (initialization, deskewing, locked) and adjust their delay parameters accordingly, allowing the system to adapt to varying skew conditions while maintaining manageable complexity through automated control.
Solution Approach 2:
The patent employs skew detection circuits that continuously monitor clock skew between domains and provide feedback to the delay line control logic. This feedback mechanism enables the system to automatically adjust delay values to compensate for skew, resolving the contradiction by providing adaptability through closed-loop control without requiring complex manual configuration.
2Adaptability or versatility
If programmable delay lines continuously adjust delays to manage clock skew, then clock skew management capability is improved, but device complexity increases
Solution Approach 1:
The delay lines are designed with programmable capabilities that allow dynamic adjustment of delay values. The system transitions through defined operating modes (initialization, deskewing, locked) where the programmable nature of the delay lines enables flexible skew management while the mode transitions provide structure to limit complexity.
Solution Approach 2:
Skew detection circuits provide continuous feedback about clock skew conditions to the delay line control logic. This automated feedback mechanism enables effective skew management without requiring complex manual intervention, as the system self-adjusts based on real-time conditions.
Solution Approach 3:
The clock distribution network performs self-adjustment through automated skew detection and delay modification. The system monitors its own skew conditions and automatically modifies delay values without external intervention, reducing the need for complex external control mechanisms while maintaining effective skew management.
3Manufacturing precision
If skew control circuit regularly adjusts programmable delay lines, then synchronization precision is improved, but productivity deteriorates due to adjustment overhead
Solution Approach 1:
The system dynamically adjusts delay values only when needed, transitioning through defined operating modes. During the locked mode, adjustments are minimized or disabled, allowing high-speed data exchange without adjustment overhead. The dynamic nature of the control allows the system to achieve precise synchronization when required while maintaining high productivity during stable operation.
Solution Approach 2:
The skew control operates periodically rather than continuously, with adjustment cycles triggered by mode transitions. The system performs skew adjustments during deskewing mode and then enters locked mode where data exchange proceeds without interruption. This periodic adjustment approach maintains synchronization precision while minimizing the impact on overall productivity.
4Productivity
If adjustment of delays is disabled in locked operating mode, then data exchange efficiency is improved, but synchronization precision may deteriorate if skew changes
Solution Approach 1:
The system maintains the ability to dynamically adjust delays even in locked mode, allowing it to respond to skew changes when necessary. The locked mode primarily disables routine adjustments to maximize data exchange efficiency, but the underlying programmable delay lines remain capable of adjustment if skew detection triggers a mode transition, thus balancing efficiency and precision.
Solution Approach 2:
The skew detection circuits continue to monitor skew conditions even in locked mode, providing feedback that can trigger mode transitions if skew exceeds acceptable thresholds. This feedback mechanism ensures that while routine adjustments are disabled for efficiency, the system can still maintain synchronization precision by transitioning to deskewing mode when skew changes occur.
Data Source
AI summary
Disclosed aspects relate to a clock distribution network of a synchronous logic device. The synchronous logic device comprises multiple sub-circuits belonging to different clock domains. The clock distribution network comprises a clock source operable for providing a global clock signal, at least one programmable delay line associated with a certain sub-circuit operable for generating a local clock signal for said sub-circuit by delaying the global clock signal or a signal derived therefrom and a global skew control circuit for managing clock skew between the local clock signals. The global skew control circuit is operable for managing clock skew between at least some local clock signals by regularly adjusting the delay caused by at least one programmable delay line when in a deskewing operating mode, and disabling adjusting the delays of the programmable delay lines when in a locked operating mode.