Clock Skew Control in Integrated Circuit Design
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Solution Overview
Problem
Designing integrated circuits with millions of transistors poses challenges in physical design and verification, particularly in managing clock skew and timing critical paths, which existing methods struggle to address effectively.
Innovation Solution
A method and system for designing integrated circuits that involve selecting state elements with a predetermined clock skew, associating them with a clock header, and generating a gate-level netlist and clock network, ensuring the state elements have the specified clock skew, thereby meeting timing requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional physical design methods are used for integrated circuits with millions of transistors, then the design complexity increases, but the ability to manage and control clock skew deteriorates
Solution Approach 1:
The patent segments the clock network into multiple hierarchical levels (global clock network and local clock networks). The global clock network distributes clock signals to multiple clock headers, while local clock networks distribute signals from each clock header to individual state elements. This segmentation allows independent optimization and control of clock skew at different levels, making it manageable even in circuits with millions of transistors.
Solution Approach 2:
The patent performs preliminary action by pre-determining clock skew values during the design phase. The system calculates and stores clock skew information in a lookup table before physical implementation. During placement and routing, the system retrieves pre-calculated skew values to guide clock network generation, ensuring precise clock skew control without requiring complex real-time adjustments in the final design.
2Adaptability or versatility
If more state elements are added to increase circuit functionality, then the circuit capability improves, but the difficulty of verifying timing critical paths increases
Solution Approach 1:
The patent implements feedback mechanisms where the system continuously monitors and adjusts clock skew based on timing analysis results. The clock network generation process uses feedback from placement information and timing requirements to iteratively optimize clock distribution. This feedback loop enables automatic verification and adjustment of timing critical paths, making verification manageable even as the number of state elements increases to millions.
3Manufacturing precision
If precise clock skew control is implemented for all state elements, then timing accuracy improves, but the device complexity increases
Solution Approach 1:
The patent applies local quality by allowing different clock skew values for different regions or groups of state elements rather than enforcing a uniform clock skew across the entire circuit. Each local clock network can have optimized skew characteristics tailored to its specific timing requirements and physical layout. This approach achieves precise clock skew control where needed while avoiding unnecessary complexity in regions with less stringent timing requirements.
Data Source
AI summary
A method for designing an integrated circuit. The method may include obtaining a register-transfer level (RTL) file for the integrated circuit. The RTL file may include hardware description language code that describes various modules for the integrated circuit. The method may further include selecting, within the RTL file, various state elements having a predetermined clock skew. The method may further include associating, in response to selecting the state elements, the state elements with a predetermined clock header. The method may further include generating a gate-level netlist using the RTL file. The state elements may be assigned to the predetermined clock header in the gate-level netlist. The method may further include generating, using the gate-level netlist, a clock network for the integrated circuit. The state elements in the clock network may have the predetermined clock skew.