Multiphase Clock Recovery Delay Calibration for Stable 3-Phase Links
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Solution Overview
Problem
Current clock generation circuits in multi-wire, multi-phase data communication links, such as the C-PHY interface, face limitations in speed and reliability due to variations in signal transition times, leading to jitter and reduced channel bandwidth, especially as signaling frequencies increase.
Innovation Solution
A method and apparatus for calibrating clock recovery circuits by incrementally adjusting a delay period until the clock signal frequency matches the desired frequency, ensuring reliable data transmission on a 3-wire, 3-phase interface by suppressing multiple transitions and optimizing loop delay to maintain symbol integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If delay circuits are employed to ensure stable signaling states, then reliability is improved, but transmission rate is limited
Solution Approach 1:
The patent implements dynamic delay adjustment by continuously monitoring the stability of signaling states on multiple wires and automatically adjusting the delay period accordingly. This allows the system to optimize between reliability and transmission rate in real-time, rather than using fixed delay values that limit performance.
Solution Approach 2:
The system changes the delay parameter dynamically based on observed signal transition characteristics. By monitoring actual signal behavior and adjusting the delay period parameter, the system adapts to varying transmission conditions to maintain both reliability and high transmission rates.
2Reliability
If maximum delay values are used to accommodate signal variations, then reliability is improved, but communication speed is reduced
Solution Approach 1:
The patent employs feedback mechanisms where the system monitors signal transition stability and uses this information to adjust the delay period. This closed-loop approach ensures that delay values are optimized for current conditions, maintaining reliability without unnecessarily reducing communication speed.
Solution Approach 2:
The system performs preliminary calibration by monitoring signal transitions and determining appropriate delay values before full-speed operation begins. This preliminary adjustment ensures that the system is properly configured for optimal performance before high-speed communication starts.
3Manufacturing precision
If delay period is increased to suppress multiple transitions, then symbol integrity is improved, but frequency accuracy deteriorates
Solution Approach 1:
The system dynamically adjusts the delay period to find the optimal value that simultaneously maintains symbol integrity and frequency accuracy. By continuously monitoring both symbol stability and clock frequency, the system adapts the delay parameter to achieve both objectives rather than prioritizing one over the other.
Solution Approach 2:
The patent changes the delay period parameter based on observed frequency deviations and symbol stability metrics. This adaptive parameter adjustment allows the system to maintain precise frequency control while ensuring symbols are properly stabilized before sampling.
Data Source
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AI summary
Methods, apparatus, and systems for clock calibration are disclosed. A method for clock data recovery circuit calibration includes configuring a first clock recovery circuit to provide a clock signal that has a first frequency and that includes a single pulse for each symbol transmitted on a 3-wire, 3-phase interface, and calibrating the first clock recovery circuit by incrementally decreasing a delay period provided by a delay element of the first clock recovery circuit until the clock signal provided by the first clock recovery circuit has a frequency that is greater than the first frequency and, when the first clock recovery circuit has a frequency that is greater than the first frequency, incrementally increasing the delay period provided by the delay element of the first clock recovery circuit until the clock signal provided by the first clock recovery circuit has a frequency that matches the first frequency.