Variable Phase Offset Clock Recovery for Multiple Clock Domains
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Solution Overview
Problem
Modern digital systems require precise synchronization of multiple clock domains to handle high-speed data transmission, but existing technologies struggle to achieve this with sufficient precision and flexibility, especially in systems using multiple clock domains.
Innovation Solution
A second-order clock recovery circuit with a feedback loop that uses phase error signals to adjust the phase of multiple clock domains, allowing for selective variable phase offset and synchronization, incorporating phase interpolators and accumulators to generate phase adjustment signals for edge and data clocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple clock domains are used for high-speed data transmission, then data transmission speed is improved, but synchronization precision between clock domains deteriorates
Solution Approach 1:
The system segments the clock recovery function into multiple independent clock domains (first clock domain for edge sampling, second clock domain for data sampling). Each domain operates with its own phase detector and control mechanism, allowing high-speed operation while maintaining precision within each domain. The segmentation enables parallel processing of different signal aspects without mutual interference.
Solution Approach 2:
A phase offset controller acts as an intermediary between the two clock domains, dynamically adjusting the phase relationship between them. This intermediary component receives feedback from both domains and coordinates their synchronization, enabling precise timing alignment despite operating at high speeds where traditional single-domain approaches fail.
2Device complexity
If fixed phase offset is used between clock domains, then device complexity is reduced, but adaptability to different data patterns deteriorates
Solution Approach 1:
The phase offset between clock domains is made dynamic rather than fixed. The phase offset controller continuously adjusts the phase relationship based on feedback from phase detectors monitoring both clock domains. This dynamic adaptation allows the system to optimize performance for different data patterns and asymmetric data eye conditions without requiring complex manual configuration.
Solution Approach 2:
The system implements self-adjusting phase control where the phase offset controller automatically calibrates the relative phase between clock domains using feedback from the phase detectors. This self-service mechanism eliminates the need for external intervention or complex predetermined configuration, allowing the system to adapt to different operating conditions autonomously.
Data Source
AI summary
A circuit for performing clock recovery according to a received digital signal 30. The circuit includes at least an edge sampler 105 and a data sampler 145 for sampling the digital signal, and a clock signal supply circuit. The clock signal supply circuit provides edge clock 25 and data clock 20 signals offset in phase from one another to the respective clock inputs of the edge sampler 105 and the data sampler 145. The clock signal supply circuit is operable to selectively vary a phase offset between the edge and data clock signals.