Bus Wire Reordering to Minimize Coupling Capacitance
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Solution Overview
Problem
Existing methods for arranging wires in integrated circuits result in significant coupling capacitance and noise due to the proximity of neighboring wires, leading to degraded signal-to-noise ratio and slowed signal propagation, especially when common timing signals are used.
Innovation Solution
A method and program product that rearrange the positions of wires in a bus to minimize coupling capacitance by altering the order of wires, such that aside from the first and last wires, each wire has progressively more coupling capacitance, with a specific pattern of 0, (N−1), 1, (N−2), ..., (N/2)−1, N/2 for even N, and 0, (N−1), 1, ..., Ceiling(N/2), Floor(N/2) for odd N, thereby reducing inductive and capacitive coupling effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If wires are arranged in sequential order (0, 1, 2, 3, ..., N-1) to simplify routing, then routing complexity is reduced, but coupling capacitance between neighboring wires increases significantly
Solution Approach 1:
The patent changes the ordering parameter of wire arrangement from sequential (0,1,2,3...) to an optimized pattern (0, N-1, 1, N-2, 2, ..., N/2). This parameter transformation reduces the coupling capacitance between adjacent wires while maintaining manageable routing complexity through a systematic reordering algorithm.
Solution Approach 2:
The patent applies different positioning strategies to different wires based on their indices. Wires are positioned according to their binary representation properties, with specific wires placed at optimized locations to minimize local coupling effects. This local optimization approach reduces overall coupling capacitance without requiring complete redesign of the routing structure.
2Area of stationary object
If wires are placed close together to maximize space utilization, then area efficiency is improved, but signal-to-noise ratio deteriorates due to increased coupling effects
Solution Approach 1:
The patent transforms the spatial arrangement parameter from compact sequential ordering to an expanded optimized pattern. By reordering wires according to the pattern (0, N-1, 1, N-2, ...), the physical spacing between coupled wires increases, reducing capacitive coupling and noise while maintaining area efficiency through systematic placement.
3Object-affected harmful factors
If wires are arranged to minimize coupling capacitance by increasing spacing, then signal-to-noise ratio is improved, but routing complexity and area increase
Solution Approach 1:
The patent applies a specific reordering transformation (0, N-1, 1, N-2, 2, ..., N/2) that achieves noise reduction through optimized spacing while avoiding exponential increase in routing complexity. The systematic nature of this transformation allows automated tools to implement it efficiently without manual intervention.
Solution Approach 2:
The patent performs wire reordering at the design stage before physical routing is finalized. By pre-calculating and applying the optimized ordering pattern (0, N-1, 1, N-2, ...) early in the design process, the routing tools can generate optimized layouts automatically, avoiding complex manual routing adjustments later.
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 minimizes coupling capacitance between wires, reducing noise and improving signal propagation by increasing the spacing between horizontal wire components, thus enhancing the signal-to-noise ratio and reducing the adverse effects of neighboring wires on signal timing.
Implementation Method 1
This invention relates to methods for resolving problems caused by coupling effects between neighboring wires, and particularly to adjusting the effects of inductive coupling and/or capacitive coupling in bus lines
Implementation Method 2
This invention relates to methods for resolving problems caused by coupling effects between neighboring wires, and particularly to adjusting the effects of inductive coupling and/or capacitive coupling in bus lines
Data Source
AI summary
A method for minimizing coupling capacitance between wires in a bus comprising shifting by rearranging the order of said wires in said bus so that, aside from said first and last wires in said arrangement, the coupling capacitance across said bus is uniform and minimized relative to the original arrangement. Alternatively, a method for minimizing coupling capacitance between wires in a bus comprising shifting by rearranging the order of said wires in said bus so that, aside from said first and last wires in said arrangement, one of said wires incurs the smallest possible amount of coupling capacitance and then the coupling capacitance across the rest of said wires in said bus gets progressively worse relative to the original arrangement.