Macromodeling and Optimization of Digital MOS VLSI Circuits

Power consumption and signal delay are crucial to the design of high-performance VLSI circuits. This paper presents CAD tools for modeling and optimizing digital MOS designs. The tools determine the transistor sizes that minimize circuit power consumption subject to constraints on signal path delays. Computational efficiency is obtained through macromodeling techniques and a specialized optimization algorithm. The macromodels are based on device equations, and encapsulate logic gate behavior in a set of simple yet accurate formulas. The optimization algorithm exploits properties of the digital MOS domain to convert the primal optimization problem into a dual form which is much easier to solve. The result is a pair of CAD tools that can optimize a circuit in roughly the amount of time needed to perform a transistor-level simulation of the circuit.