Programmable Clock Delay Line for Continuous Skew Adjustment
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Solution Overview
Problem
In computer systems with multiple clock domains, achieving synchronization between clock signals is challenging due to differences in clock tree latency, leading to data loss and faults, especially when frequency changes occur, requiring efficient methods to minimize skew between clock signals.
Innovation Solution
A method involving a programmable delay line in the clock tree, where a history observing unit adjusts delays based on measured skew differences compared to a target skew, using iterative measurements and control system response time analysis to maintain synchronization across clock domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a programmable delay line is used to adjust skew between clock signals, then synchronization precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the measured skew value is continuously compared with a target skew value, and the programmable delay line is adjusted based on the comparison result. This closed-loop feedback system enables precise skew adjustment while automating the calibration process, reducing the need for manual intervention and complex external testing equipment.
Solution Approach 2:
The system performs self-calibration by automatically measuring its own skew and adjusting its delay line without requiring external test equipment or manual intervention. The skew measurement unit, comparison unit, and delay line work together in an autonomous manner to maintain optimal synchronization, making the system self-sufficient for skew management.
2Reliability
If iterative skew measurement and adjustment is performed, then synchronization reliability is improved, but time consumption increases
Solution Approach 1:
The patent performs preliminary skew calibration during system initialization or startup phase, establishing the correct delay settings before normal operation begins. This preliminary action ensures that the system starts with optimal synchronization parameters, avoiding the need for continuous iterative adjustments during runtime and reducing time consumption during critical operational phases.
Solution Approach 2:
The system maintains continuous skew monitoring and adjustment capability, ensuring that synchronization is constantly maintained without interruption. The iterative measurement and adjustment process operates continuously or periodically to adapt to changing conditions, ensuring reliable synchronization while minimizing downtime or performance degradation.
3Reliability
If skew adjustment is performed frequently to maintain synchronization, then data exchange reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic skew measurement and adjustment rather than continuous adjustment. The system measures skew at predetermined intervals or under specific conditions (such as frequency changes or temperature variations), adjusting the delay line only when necessary. This periodic approach maintains data exchange reliability by correcting skew when it deviates from targets, while significantly reducing power consumption compared to continuous adjustment.
Data Source
AI summary
A method for adjusting a skew between a second clock signal and a first clock signal is provided. The second clock signal has been propagated from a first clock source through a second clock tree. The second clock tree comprises a programmable delay line that induces a delay. The method comprises at least one iteration of: measuring a skew between the second clock signal and the first clock signal, comparing an absolute difference of the measured skew and a sum of delay changes initiated in a time window preceding the measurement with a target skew, and initiating a delay change of the delay induced by the programmable delay line in the second clock tree depending on a result of the comparison.