Polymorphic Circuit Simulation with Selective Transmission Line Extraction
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Solution Overview
Problem
The process of simulating and editing large-scale integrated circuits is challenging due to non-ideal connections in RF or microwave circuits and high-speed digital circuits, as existing CAD tools require complex rule sets and tedious device extraction, leading to altered ideal circuits outside designer control.
Innovation Solution
A method in a data processing system that allows designers to specify interconnects using user-selectable line definitions, converting them into transmission line devices for simulation, enabling easy editing and simulation model changes without altering the layout or schematic, using models like nodal short, analytical transmission line, EM, or coupled parallel line models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If device extraction is performed using complex rule sets, then transmission line devices can be extracted from layout, but the process becomes tedious and error-prone
Solution Approach 1:
The patent segments the extraction process by allowing selective extraction of specific interconnects rather than processing the entire layout. Designers can choose which interconnects to extract and which to ignore, dividing the complex extraction task into manageable portions that reduce errors and improve control.
Solution Approach 2:
The patent introduces user-selectable parameters including extraction thresholds, minimum length criteria, and model type selections. These adjustable parameters allow the extraction process to adapt to different design requirements, making both accurate extraction and ease of operation achievable by tuning parameters rather than relying on fixed complex rules.
2Reliability
If interconnects are replaced with extracted devices, then transmission line effects can be simulated, but layout editing becomes difficult
Solution Approach 1:
The patent implements a dynamic workflow where the extraction process can be activated or deactivated based on editing needs. When layout editing is required, the extraction process can be temporarily disabled, allowing designers to modify interconnects without triggering re-extraction. This dynamic control maintains simulation accuracy when needed while enabling flexible editing when required.
Solution Approach 2:
The patent allows preliminary selection and marking of interconnects for extraction before final simulation. Designers can pre-identify which interconnects need extraction and assign them specific models in advance. This preliminary organization allows for easier editing later, as the system knows which elements are extracted and can selectively re-process only those portions rather than the entire layout.
3Device complexity
If ideal wires are used in schematic, then circuit design is simplified, but non-ideal connection effects are not captured
Solution Approach 1:
The patent applies local quality by maintaining ideal wire representations in the majority of the circuit while selectively introducing transmission line models only at specific locations where non-ideal effects are significant. This allows the circuit to remain mostly simple and intuitive, with enhanced accuracy applied locally to critical interconnects that require transmission line treatment.
Solution Approach 2:
The patent introduces transmission line models as intermediary elements between the ideal schematic representation and the physical layout. These transmission line devices act as mediators that capture non-ideal effects without requiring complete redesign of the schematic. The intermediary transmission line models bridge the gap between simplified representation and accurate simulation.
4Reliability
If device extraction is performed on entire circuit, then all transmission line devices are extracted, but computational workload increases
Solution Approach 1:
The patent enables partial extraction by allowing designers to select only the portions of the circuit that require transmission line modeling. Instead of extracting all interconnects, the system can be configured to extract only those meeting specific criteria such as minimum length, specific locations, or particular signal types. This partial action reduces computational workload while maintaining completeness for the extracted portions.
Data Source
AI summary
A method for operating a data processing system to simulate a circuit that includes a plurality of circuit devices connected by interconnects. A layout description of the circuit is provided in which the devices are connected by interconnects. Each interconnect is associated with a line definition that includes a physical description of an interconnect between two of the circuit devices and a simulation model to be used in simulating the interconnect during simulations of the circuit. The line definitions are user selectable from a list of available line definitions. A circuit netlist is generated by reading physical interconnects from the layout. At least one of the interconnects is replaced by a plurality of transmission line devices, each device being associated with the simulation model included in the line definition. The circuit is then simulated using the netlist.