Multi-Lane Synchronous Reset Circuit for Coherent Receiver Timing
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Solution Overview
Problem
Existing computing systems face challenges in synchronizing control signals for high-speed communication, particularly in receivers and de-serializer circuits, leading to issues with data alignment and timing errors across multiple lanes.
Innovation Solution
A synchronous reset circuit is introduced, comprising sub-circuits that sample reset signals based on low-speed and high-speed clock signals, measure phase relations, and select between positive and negative sampled reset signals to generate a synchronized reset signal, ensuring alignment with high-speed clock transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If control signals are synchronized for high-speed communication, then data alignment and timing accuracy are improved, but circuit complexity increases
Solution Approach 1:
The reset circuit is divided into multiple independent sub-circuits, each responsible for a specific lane. Each sub-circuit contains phase detectors, sample-and-hold circuits, and control logic that operate independently to generate lane-specific reset signals synchronized to the high-speed clock, thereby achieving precise timing control without requiring a monolithic complex circuit
Solution Approach 2:
A low-speed reference clock is introduced as an intermediary signal to coordinate the reset generation process. The reference clock at a lower frequency (e.g., 1/4th of the high-speed clock) provides a manageable timing基准 that simplifies the phase detection and reset synchronization process, reducing the complexity of directly synchronizing to the high-speed clock while maintaining timing accuracy
2Measurement precision
If sampling rate is increased to reduce jitter, then timing precision is improved, but circuit complexity and power consumption increase
Solution Approach 1:
The circuit uses periodic sampling of the reset signal at specific phases of the high-speed clock cycle. By strategically selecting sampling points (e.g., at quarter-cycle intervals using the reference clock), the circuit achieves accurate timing synchronization without requiring continuous high-rate sampling, thereby reducing circuit complexity while maintaining timing precision
Solution Approach 2:
The same sub-circuit architecture is reused across multiple lanes to generate synchronized reset signals. Each lane's reset sub-circuit performs the same functions (phase detection, sampling, signal generation) but is tailored to its specific lane's clock phase, achieving universal applicability that reduces overall system complexity through repetition of proven modular blocks
Data Source
AI summary
A reset sub-circuit can sample the reset signal based on a low-speed clock reference signal to generate a series of sampled reset signals. A phase relation between a first selected one of the series of sampled reset signals and the high-speed clock signal at the clock input of each sampler can be measured to generate reset trigger signals corresponding to each of a plurality of samplers. A second selected one of the series of sampled reset signals can be sampled based on the high-speed clock signal to generate a positive sampled reset signal and a negative sampled reset signal. The reset sub-circuit can select between the positive sampled reset signal and the negative sampled reset signal based on the reset trigger signals corresponding to each sampler to generate the synchronous reset signal.