Multi-Lane Clock Gating with Duty Correction for Jitter Control
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Solution Overview
Problem
In high-speed communication systems, half-rate architectures experience jitter due to duty errors in clock signals, leading to operational limitations in circuit synchronization and speed.
Innovation Solution
A circuit system with a clock tree circuit, duty correction circuits, clock gating circuits, and variable delay circuits that correct duty ratios and timing of clock signals, ensuring synchronized operation across multiple lanes without skew mismatch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If half-rate architecture is used to achieve high-speed communication, then data rate is improved, but duty error causes jitter and limits operational speed
Solution Approach 1:
The system divides the clock distribution into multiple independent lanes (first lane, second lane, etc.), each with its own duty correction circuit and clock gating circuit. This segmentation allows independent correction of duty errors in each lane, preventing jitter from propagating across the entire system while maintaining high-speed operation.
Solution Approach 2:
A duty correction circuit is introduced as an intermediary component between the clock tree circuit and the clock gating circuits. This intermediary corrects duty errors in the clock signals before they reach the gating circuits, thereby eliminating the root cause of jitter and enabling reliable high-speed communication.
2Reliability
If duty correction circuits are added to correct clock signals, then clock signal stability is improved, but device complexity increases
Solution Approach 1:
The duty correction functionality is segmented and distributed to individual lanes rather than implementing a complex centralized correction system. Each lane has its own simple duty correction circuit that operates independently, reducing overall system complexity while achieving reliable clock signal correction across all lanes.
Solution Approach 2:
Each lane's duty correction circuit autonomously corrects duty errors in its own clock signal without requiring complex coordination with other lanes. The variable delay circuits automatically adjust timing based on detected skew, enabling self-correcting operation that simplifies the overall control architecture.
3Productivity
If multiple clock gating circuits operate simultaneously, then productivity is improved, but skew mismatch causes operational errors
Solution Approach 1:
Skew detection circuits continuously monitor timing relationships between clock signals from different lanes and provide feedback to variable delay circuits. This feedback mechanism dynamically adjusts delay times to maintain proper synchronization, enabling multiple clock gating circuits to operate simultaneously without skew-related errors.
Solution Approach 2:
The system employs dynamically adjustable delay times in variable delay circuits rather than fixed delays. This allows the system to adapt to changing timing conditions and maintain synchronization accuracy even as operating conditions vary, enabling reliable parallel operation of multiple clock gating circuits.
Data Source
AI summary
A circuit system is disclosed. In one example, the circuit system includes a clock tree circuit with multiple lanes to which a clock signal is distributed. A duty correction circuit is provided for each of the multiple lanes, and corrects a duty ratio of the clock signal. A clock gating circuit group has a clock gating circuit for each of the multiple lanes and receives, as input, the clock signal from the duty correction circuit. The clock gating circuit group starts output of the clock signal from each of a plurality of the clock gating circuits in a predetermined period. A variable delay circuit is provided in association with each of a plurality of the duty correction circuits and is capable of changing a delay time of a control signal that controls a timing of starting output of the clock signal from the clock gating circuit.