Integrated Circuit Cell Replacement for Frequency Targets
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Solution Overview
Problem
Integrated circuit designers face challenges in modifying existing designs to achieve different maximum operating frequency and power consumption targets without significant redesign efforts, as conventional methods require repeating multiple steps in the design process, including placement and routing of cells and signal timing analysis.
Innovation Solution
A data processing system uses analytical cost functions to identify and replace cells in an integrated circuit design, allowing for efficient modification of the design to achieve new frequency-power characteristics by swapping cells with lower threshold voltages, while maintaining the same areal dimensions and configurations, thus avoiding the need for re-routing wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If MOSFETs with low threshold voltage are used to increase maximum operating frequency, then speed is improved, but power consumption increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the threshold voltage parameter of MOSFETs across different cells in the integrated circuit. By selecting cells with different threshold voltage values from a library of candidate cells, the design can optimize the balance between speed and power consumption for each specific cell based on its location and function within the circuit architecture.
2Adaptability or versatility
If conventional design modification methods are used to achieve new frequency targets, then design flexibility is improved, but design time and cost increase
Solution Approach 1:
The patent applies preliminary action by pre-characterizing multiple candidate cells with different threshold voltage values before the actual design process. These pre-characterized cells are stored in a library with their speed and power consumption properties already determined, allowing rapid selection and substitution during design modification without requiring time-consuming re-characterization or full redesign cycles.
Solution Approach 2:
The patent applies universality by creating a library of candidate cells that can serve multiple functions depending on where they are placed in the circuit. The same set of pre-characterized cells can be used across different design iterations and frequency targets, making the design process more efficient and reducing the need for application-specific custom cell designs.
3Speed
If cells are replaced to achieve new frequency targets, then operating frequency is improved, but design complexity increases
Solution Approach 1:
The patent applies local quality by selectively replacing only those specific cells that have the greatest impact on achieving the target frequency, rather than uniformly replacing all cells throughout the circuit. This targeted approach reduces design complexity by limiting the scope of modifications to critical path cells while leaving other cells unchanged.
Data Source
AI summary
A first integrated circuit design with a first maximum operating frequency is modified to achieve a second integrated circuit design with a second maximum operating frequency. The integrated circuit design comprises an arrangement of cells. Each of these cells drives a signal that propagates through a net of other circuit elements to one or more nodes that are limited by respective signal timing constraints. An analytical cost function is assigned to each of the cells. Each analytical cost function comprises a value for its respective cell that is based on one or more speed-related factors indicative of the impact of the respective cell on the first maximum operating frequency of the first integrated circuit design. One or more of the cells are replaced with different cells based on the determined analytical cost functions.