Chiplet Clock Delay Compensation for Cross-Chiplet Skew
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Solution Overview
Problem
In multi-chip systems, clock signals propagating through clock distribution trees often become misaligned due to variations in hardware manufacturing and environmental conditions, leading to clock skew, which can disrupt the synchronized operation of cascading logic units.
Innovation Solution
The system employs phase detectors to measure phase measurements indicative of clock signal propagation speeds across chiplets, and a microcontroller adjusts delay offsets using delay units to synchronize clock signals, ensuring proper alignment and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If physical layer interface is used to drive data between logic units, then data transfer capability is improved, but circuit complexity and power consumption increase
Solution Approach 1:
The patent extracts the physical layer interface from the direct connection path by introducing a clock delay compensation mechanism that operates at the boundary between logic units. This allows data to be transferred directly without full physical layer processing, reducing complexity while maintaining high data transfer rates through controlled clock synchronization.
2Device complexity
If direct connection between logic units is used, then overhead is reduced, but clock synchronization difficulty increases
Solution Approach 1:
The patent introduces a clock delay compensation mechanism as an intermediary between logic units. This intermediary measures clock phase differences and adjusts delays to maintain synchronization, enabling direct connections without the complexity of full physical layer interfaces while solving the clock synchronization problem.
Solution Approach 2:
The patent implements feedback by continuously monitoring clock phase differences between logic units and dynamically adjusting delay offsets. The phase detector measures synchronization status and feeds this information back to the delay compensation mechanism, which adjusts its operation to maintain optimal clock alignment across directly connected logic units.
3Reliability
If clock signals are distributed across chiplets, then synchronized operation is enabled, but clock skew increases due to manufacturing variations
Solution Approach 1:
The patent applies dynamics by making the clock delay compensation adjustable rather than fixed. The delay offset for each chiplet can be dynamically tuned based on measured phase differences, allowing the system to adapt to manufacturing variations and environmental changes while maintaining synchronized operation across all chiplets.
Solution Approach 2:
The patent changes the parameter of clock delay by introducing adjustable delay offsets for each chiplet. By varying these delay parameters based on measured phase differences, the system compensates for manufacturing variations in clock distribution and maintains precise synchronization across multiple chiplets.
Data Source
AI summary
Methods and systems are disclosed for clock delay compensation in a multiple chiplet system. Techniques disclosed include distributing, by a clock generator, a clock signal across distribution trees of respective chiplets; measuring phases, by phase detectors, where each phase measurement is associated with a chiplet of the chiplets and is indicative of a propagation speed of the clock signal through the distribution tree of the chiplet. Then, for each chiplet, techniques are further disclosed that determine, by a microcontroller, based on the phase measurements associated with the chiplet, a delay offset, and that delay, based on the delay offset, the propagation of the clock signal through the distribution tree of the chiplet using a delay unit associated with the chiplet.