1. Field of the Invention
The present invention relates to circuit design, especially the design of integrated circuits.
2. Description of the Prior Art
Integrated circuit design typically requires several steps: topology selection, sizing of circuit devices that comprise the circuit, and layout of the circuit devices that define the circuit. Topology selection involves choosing an interconnection of circuit devices to implement a desired function. Examples of circuit devices include transistors, resistors, capacitors and the like. Circuit sizing involves the use of a circuit synthesizer for automatically sizing the circuit devices utilizing numerical techniques to search a defined design space. Layout of the circuit devices involves the manual or automated layout of the circuit devices based on the sizes of the circuit devices determined by the circuit synthesizer during sizing of the circuit devices.
Currently, circuit synthesizers are optimization-based and utilize numerical techniques to search a defined design space. A design space is typically comprised of many design points, where a design point is comprised of a topology of the circuit devices for the circuit and the performances associated with the topology. One problem associated with the use of a circuit synthesizer is that the design space for many circuits may contain millions of design points, with industrial circuits containing trillions of design points or more. Because of this huge number of design points, the design space cannot be effectively explored utilizing exhaustive search techniques to evaluate each design point. An intelligent search process is, therefore, necessary to find a design point that meets the user-specified performance specifications and is optimal in terms of area, power, and/or some other measure of merit.
In operation, each design point simulated by a circuit synthesizer is evaluated to determine how far the current design point's performances are from predefined performance specifications for the circuit. The result of this determination is typically called the cost of the design point. Circuit synthesizers are configured to search the design space to find the best design point, i.e., the design point having the smallest cost, that meets the performance specifications. Circuit synthesizers are good at finding the best design point to meet performance specifications. However, circuit synthesizers are not good at finding tradeoff relationships between competing performance specifications. The present invention is targeted at identifying high quality design points wherein tradeoff relationships between competing performance specifications are considered.