A macromodeling approach to the synthesis of analog circuits using circuit decomposition and numerical circuit analysis

The approach to analog circuit design automation described seeks to blend the advantages of the analytical modeling approach with the generality of the SPICE-based approach. Researchers developing techniques to automate the design of analog circuits usually approach the design problem having in mind the analog circuit as one piece. The results are that design automation of analog circuits is held back from progress beyond a certain circuit size limit and/or a limited range of circuit topologies. It is shown that the size limitation can be overcome by using a circuit decomposition and augmentation process. The range of topologies can be greatly extended by using a simulation tool. Using these augmented subcircuits and associated simulation data, the work is extended to provide macromodels which analytically express the circuit's performance in terms of its design parameters at the parent level. These macromodels can the be used as the basis of a very fast and efficient optimization scheme. The techniques were used in macromodel building of an op amp circuit.>