Crossbar Switch Delay Characterization Using Base and Fanout Delays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Characterizing crossbar switches with resistance change elements is time-consuming and labor-intensive due to the need to calculate numerous combinations of delays caused by varying fanout numbers and inter-CLB wiring resistances, leading to increased man-hours and potential delay errors.
Innovation Solution
A numerical information generation apparatus and method that calculate a base delay excluding load capacitance influence and a correction delay caused by fanout, allowing for efficient delay calculation of each crossbar switch by separating delays into these components, reducing the number of necessary calculations and man-hours required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional characterization methods are used to calculate delays for all combinations of fanout numbers and inter-CLB wiring resistances, then measurement precision is improved, but loss of time increases significantly
Solution Approach 1:
The delay calculation is segmented into two independent components: base delay (calculated once for each crossbar switch regardless of fanout) and correction delay (calculated based on fanout number). This segmentation allows the base delay to be computed once rather than for every combination of fanout and resistance, dramatically reducing characterization time while maintaining accuracy through the additive combination of the two delay components.
Solution Approach 2:
The base delay is calculated in advance as a preliminary step before considering fanout effects. By pre-calculating the base delay component that is independent of fanout number, the method avoids redundant calculations when analyzing different fanout scenarios, thus reducing overall characterization time while preserving measurement precision.
2Manufacturing precision
If detailed characterization of all delay combinations is performed, then manufacturing precision is improved, but productivity decreases due to increased man-hours
Solution Approach 1:
The characterization process is divided into two stages: base delay characterization (independent of fanout) and correction delay characterization (dependent on fanout). This segmentation reduces the total number of calculations required while maintaining manufacturing precision, as the base delay is computed once and reused across all fanout scenarios.
Solution Approach 2:
The method changes the approach from calculating total delay as a function of multiple parameters (fanout and resistance) simultaneously to calculating base delay and correction delay as separate parameter-dependent components. This parameter separation allows for more efficient computation while maintaining the precision needed for manufacturing.
3Area of stationary object
If resistance change elements are used to reduce chip area, then area of stationary object is reduced, but device complexity increases due to delay calculation challenges
Solution Approach 1:
The delay characterization for resistance change element-based crossbar switches is simplified by segmenting the calculation into base delay and correction delay components. This segmentation reduces the computational complexity from requiring full combinatorial analysis of all fanout and resistance combinations to a more manageable two-stage process.
Solution Approach 2:
The complex multi-parameter delay calculation is transformed into separate single-parameter calculations: base delay as a function of resistance only, and correction delay as a function of fanout only. This parameter separation reduces device complexity while enabling accurate delay characterization for compact crossbar switch designs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces the time and effort needed for characterizing crossbar switches while maintaining accuracy by separating delays into base and correction components, effectively managing delay errors and improving efficiency in programmable logic integrated circuits.
Implementation Method 1
A resistance value can be changed by applying a forward bias or a reverse bias to both ends of the resistance change element, and a ratio between a low resistance state (on state) and a high resistance state (off state) is 10 to the 5th power or more. That is, the resistance change element functions as a switch that can electrically connect or disconnect the first wiring and the second wiring.
Data Source
AI summary
A numerical information generating apparatus receives information of a programmable logic integrated circuit that includes a plurality of crossbar switches each including resistance change elements, calculates, for each of the plurality of crossbar switches, a base delay that is a delay in which influence of a load capacitance of other crossbar switch is excluded and a correction delay that is a delay caused by influence of a fanout of other crossbar switch, and further calculates a delay of each of the plurality of crossbar switches based on the base delay and the correction delay corresponding to each of the plurality of crossbar switches.