Clock Deskew Circuit for Multi-Phase Data Phase Alignment
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Solution Overview
Problem
Existing clock circuits face challenges in aligning transmitted data signals with received clock signals, particularly in high-speed systems using multi-phase clocking schemes, where ensuring phase alignment across multiple data symbols and clock transitions is complex and inefficient.
Innovation Solution
The proposed solution involves an integrated circuit design with a master clock generator and slave delay lines that produce multiple clock phases, phase interpolators, and a loop circuit with phase detectors and control logic to align input and output clock signals, ensuring phase matching and timing alignment of data signals through balanced clock trees and multiplexers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional DLL circuits with matching delay circuits are used to align clock signals, then phase alignment accuracy is improved, but device complexity increases due to multiple dummy buffers and matched delay lines
Solution Approach 1:
The patent uses a dummy clock path that copies the structure and delay characteristics of the real clock path. By creating an identical replica (copy) of the clock distribution network with matching buffers and delay elements, the system can measure and adjust phase alignment without adding complex control circuitry. The dummy path serves as a template that simplifies the overall design while maintaining precision.
Solution Approach 2:
The patent introduces a phase detector as an intermediary component that measures the phase difference between the real and dummy clock paths. This intermediary device translates the complex phase alignment problem into a measurable signal that can be used to control delay elements, simplifying the overall system while maintaining alignment accuracy.
2Measurement precision
If multiple delay lines and phase comparators are used in DLL circuits, then clock phase alignment is improved, but manufacturing precision requirements increase
Solution Approach 1:
By creating a dummy clock path that is a precise copy of the real clock path, the patent ensures that both paths experience identical manufacturing variations. This copying approach cancels out systematic delays and reduces the impact of manufacturing precision requirements, as any variations affect both paths equally and can be compensated through phase detection.
Solution Approach 2:
The patent uses controllable delay elements whose delay parameters can be adjusted based on measured phase differences. By dynamically changing the delay parameters rather than relying solely on fixed manufacturing precision, the system achieves accurate clock alignment while reducing the stringency of manufacturing requirements.
3Reliability
If traditional clock alignment circuits are used in high-speed multi-phase systems, then data transmission reliability is improved, but productivity decreases due to complex timing control
Solution Approach 1:
The patent implements a feedback mechanism where the phase detector continuously monitors the phase relationship between clock and data signals and adjusts the delay elements accordingly. This closed-loop feedback system automatically maintains reliable timing alignment without requiring complex external timing control, improving both reliability and productivity by eliminating manual timing adjustments.
Solution Approach 2:
The clock alignment circuit serves itself by using the dummy path to automatically measure and compensate for phase errors. The system performs its own timing calibration without external intervention, reducing the complexity of timing control while maintaining high-speed data transmission reliability.
Data Source
AI summary
An integrated circuit includes clock deskew circuitry. The deskew circuitry includes a loop circuit to align an input clock signal with an output clock signal, and also aligns transmitted data with the output clock signal.