Constraint-Programmed Initial Sizing of Analog Operational Amplifiers

摘要

This paper presents a new method to automate the initial sizing of operational amplifiers. The method emulates the manual design procedure. The sizing task is formulated as a constraint programming problem. Two new algorithms are introduced: First, a hierarchical structural analysis of functional blocks that automatically sets up the analytical equations for the sizing. And second, a heuristic to guide branching process of a constraint programming solver. We achieve a reproduction of the manual proceeding of designers and at the same time an automation of the set-up of the design problem, reducing the set-up effort from months to seconds. 16 topologies, including different variants of two-stage, folded-cascode, telescopic and symmetrical op-amps, are considered at this time. In this paper, experimental results for a two-stage op-amp and a folded-cascode op-amp are presented to show the effectiveness of the approach.