Phase Interpolator Control Loop for Clock Signal Synchronization
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Solution Overview
Problem
In high-performance chip-to-chip communication systems, the distributed clock signal often loses phase alignment with the received clock signal due to variations in temperature and supply voltage, leading to data detection errors.
Innovation Solution
A control loop comprising phase interpolators, a clock distribution network, and data receivers is used to continuously adjust the phase of the distributed clock signal to match the received clock signal, employing phase interpolation and control logic to maintain synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If delay lines and phase interpolators are adjusted during initialization to match the distributed clock signal with the received clock signal, then phase alignment is achieved initially, but phase misalignment occurs after initialization due to temperature and supply voltage variations
Solution Approach 1:
The patent implements a feedback mechanism where the data receiver samples the received data using the distributed clock signal and feeds back information about sampling quality to a control logic unit. The control logic unit adjusts the phase interpolators based on this feedback to maintain optimal phase alignment despite temperature and voltage variations, thereby resolving the contradiction between initial alignment and long-term stability.
Solution Approach 2:
The patent transitions from a static phase alignment approach (fixed during initialization) to a dynamic approach where phase interpolators are continuously or periodically adjusted based on real-time feedback. This allows the system to adapt to changing environmental conditions and maintain phase alignment stability throughout operation.
2Adaptability or versatility
If the clock distribution network characteristics change due to temperature, supply voltage, or other variables, then environmental adaptability is improved, but phase misalignment and data detection errors increase
Solution Approach 1:
The feedback loop continuously monitors data sampling quality and adjusts the distributed clock signal phase in response to environmental changes. When temperature or voltage variations cause phase drift, the feedback mechanism detects resulting data sampling errors and commands phase corrections, thereby maintaining data detection accuracy despite improved environmental adaptability of the clock distribution network.
Solution Approach 2:
The system performs self-correction of phase alignment through automated control logic that monitors its own performance and adjusts parameters without external intervention. The data receiver and control logic work together to automatically compensate for environmental variations, allowing the system to maintain reliability while adapting to changing conditions.
3Measurement precision
If phase interpolators are used to adjust the distributed clock signal phase, then phase alignment is improved, but device complexity increases
Solution Approach 1:
The patent divides the clock distribution network into multiple segments, each with its own phase interpolator that can be independently controlled. This segmentation allows for distributed phase adjustment throughout the clock tree, improving alignment precision without requiring a single complex control mechanism. Each segment handles local phase corrections, reducing overall system complexity.
Data Source
AI summary
A circuit to synchronize the phase of a distributed clock signal to a received clock signal. Embodiments include a control loop comprising a phase interpolator, a clock distribution network, and a data receiver. The clock distribution network provides a sampling clock signal to clock the data receiver. The data receiver receives as its input the received clock signal. Control logic maps a subset of the output samples to a value, and this value is added to the phase introduced by the phase interpolator to provide an updated phase. Embodiments include a second phase interpolator and a second distribution network to clock a second data receiver, where the second data receiver receives the data. The control logic adjusts the second phase interpolator in the same way that it adjusts the phase interpolator. The two data receivers are matched to each other, and the two clock distribution networks are matched to each other. Other embodiments are described and claimed.