Clock Tree Deskew Timing for Control Response Measurement
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Solution Overview
Problem
In computer systems with multiple clock domains, existing technologies face challenges in synchronizing clock signals to minimize skew, which can lead to data loss and faults, especially when clock tree latencies differ significantly between semiconductor circuits.
Innovation Solution
A method and logic device that utilize programmable delay lines and skew sensors to measure and adjust the delay between clock signals, ensuring synchronization by deskewing the second clock signal with respect to the first clock signal, and determining the control system response time to maintain alignment even with changing cycle times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If programmable delay lines are used to adjust clock signal delays, then skew between clock signals is minimized, but device complexity increases
Solution Approach 1:
The system performs self-calibration by automatically measuring skew between clock signals and adjusting delay elements without external intervention. The calibration sequence is initiated automatically, and the system uses its own resources (skew sensors, delay elements) to correct its own timing issues, reducing the need for complex external control circuitry.
Solution Approach 2:
The system implements a feedback mechanism where skew sensors continuously monitor the timing difference between clock signals, and this information is fed back to control logic that adjusts delay elements accordingly. This closed-loop feedback enables automatic skew compensation while maintaining relatively simple hardware architecture.
2Reliability
If skew measurement and adjustment is performed continuously, then synchronization is maintained under changing conditions, but use of energy increases
Solution Approach 1:
Instead of continuous adjustment, the system performs skew calibration periodically at predetermined intervals or when triggered by specific events (such as clock frequency changes). This periodic approach maintains synchronization reliability while significantly reducing energy consumption compared to continuous operation.
Solution Approach 2:
The system maintains clock signal propagation continuously while performing intermittent calibration. The useful action of clock distribution continues uninterrupted, and calibration is performed in brief sequences that do not halt system operation, thereby maintaining energy efficiency while ensuring synchronization.
3Measurement precision
If multiple skew sensors are used to measure skew in different directions, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The skew measurement function is segmented into multiple directional sensors, each measuring skew in a specific direction or phase relationship. This segmentation allows precise measurement of complex skew conditions while keeping each individual sensor relatively simple in structure.
Solution Approach 2:
The skew sensors are designed to measure multiple types of skew conditions (rising edge skew, falling edge skew, differential skew) using a unified measurement architecture. This multi-functionality reduces the need for separate specialized sensors for each measurement type, thereby reducing overall device complexity while maintaining measurement precision.
Data Source
AI summary
Measuring a control system response time of a second clock tree is provided, comprising measuring a skew between the second clock signal and the first clock signal and storing the skew, initiating a delay change of a delay induced by the programmable delay line and starting a time measurement. At least one iteration is performed of measuring the skew between the second clock signal and the first clock signal and comparing the measured skew with the stored skew. Based on the result of the comparison, stopping after a current iteration and stopping the time measurement. A result of the time measurement is the control system response time.