Delay Compensation Circuit for Clock Skew in Semiconductor Paths
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Solution Overview
Problem
Semiconductor devices face challenges in reducing clock skew and increasing integration density due to the need for symmetrical clock trees, which often require a large number of devices and can lead to jitter and reduced eye margin at high frequencies.
Innovation Solution
A semiconductor device design that includes an internal clock generation circuit, synchronized unit circuits, transfer circuits with adjustable delay times, and a delay compensation circuit to match delay times across different transfer paths, reducing the number of devices in the clock tree and enhancing integration density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If symmetrical clock trees are disposed to reduce clock skew, then clock skew between clock signals is reduced, but the number of devices in the clock tree increases, degrading integration density
Solution Approach 1:
The patent applies asymmetry by using different numbers of repeaters in different clock tree branches (first clock tree has different repeater counts than second clock tree) while still achieving clock skew compensation through the delay compensation circuit, thereby reducing device count while maintaining reliability
Solution Approach 2:
The patent changes the delay parameter dynamically by adjusting the delay time of the delay compensation circuit based on detected clock skew, allowing the system to compensate for skew without requiring symmetrical hardware configurations, thus improving integration density while maintaining clock signal reliability
2Device complexity
If the number of devices in the clock tree is reduced to improve integration density, then integration density increases, but clock skew between clock signals increases
Solution Approach 1:
The patent implements feedback by using a detection circuit to monitor clock skew between first and second clock signals, and using this feedback to adjust the delay compensation circuit, thereby maintaining clock skew compensation with reduced device count and improved integration density
Solution Approach 2:
The patent introduces a delay compensation circuit as an intermediary element that mediates between the clock generation circuit and the unit circuits, compensating for clock skew without requiring symmetrical clock tree configurations, thus enabling reduced device count while maintaining reliability
3Reliability
If symmetrical clock trees are used to reduce clock skew, then clock skew is reduced, but jitter increases and eye margin decreases at high frequencies
Solution Approach 1:
The patent applies local quality by providing different numbers of repeaters to different clock tree branches (first clock tree branch has different repeater configuration than second branch), tailoring the clock signal quality locally to each branch's specific requirements, thereby reducing jitter and maintaining eye margin while still compensating for clock skew
Data Source
AI summary
A semiconductor device includes an internal clock generation circuit configured to generate an internal clock; a plurality of unit circuits configured to have a first unit circuit and a second unit circuit operating while being synchronized with an internal clock; a plurality of transfer circuits including a first transfer circuit configured to provide a first transfer path having a first delay time, and a second transfer circuit configured to provide a second transfer path having a second delay time different from the first delay time; and a delay compensation circuit configured to compare a first clock input to the first unit circuit through the first transfer path with a second clock input to the second unit circuit through the second transfer path, and to adjust the second delay time so that the adjusted second delay time matches the first delay time.