Bidirectional Clock Tree Delay Tuning for Branch Skew Control
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Solution Overview
Problem
Clock skew, caused by variations in branch length and stages within clock trees in integrated circuit devices, affects the operational efficiency and latency of logic elements, particularly in larger and programmable logic devices like FPGAs.
Innovation Solution
Incorporating a clock switch block with tunable delay buffers that adjust the clock signal based on feedback clock signals from different branches to determine and mitigate phase variations, ensuring coordinated operation across logic regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the clock tree size increases to cover more logic regions, then the coverage area increases, but the clock skew magnitude increases
Solution Approach 1:
The patent divides the clock tree into multiple segments with individual delay buffers inserted at strategic points along different branches. Each segment can be independently adjusted to compensate for path length variations, allowing large clock trees to maintain synchronization across extended coverage areas while minimizing cumulative skew effects.
2Area of stationary object
If the branch length variation increases to reach more logic regions, then the coverage area increases, but the clock skew magnitude increases
Solution Approach 1:
The patent applies different delay compensation values to different branches of the clock tree based on their specific path lengths and loading characteristics. Each branch receives customized delay adjustment through programmable delay buffers, allowing precise local optimization of clock signal timing while maintaining overall system coherence across diverse branch configurations.
3Area of stationary object
If more stages (muxes or buffers) are added to the clock tree, then the coverage area and functionality increase, but the clock skew magnitude increases
Solution Approach 1:
The patent inserts delay buffers at predetermined locations along clock tree branches before the clock signal reaches logic elements. These pre-positioned buffers proactively compensate for anticipated skew accumulation from subsequent stages, allowing the system to maintain timing precision even as additional muxes and buffers are added to expand functionality and coverage.
Data Source
AI summary
The present disclosure provides systems and methods for improving operation of integrated circuit device including a logic region, which includes a plurality of logic gates that operate based at least in part on a clock signal to facilitate providing a target function, and a clock tree, which includes a clock switch block that receives a source clock signal from a clock source and a branch communicatively coupled between the clock switch block and the logic region, in which the branch operates to provide the clock signal to the logic region based at least in part on the source clock signal and the branch includes a tunable delay buffer that operates to apply a delay to the clock signal based at least in part on a clock skew expected to be introduced by the branch.