Optimal Design of Low-Voltage, Two-Stage CMOS Op-amp Using Evolutionary Techniques

Abstract

This article explores the comparative optimizing efficiency of particle swarm optimization (PSO) and simplex-PSO method for the design of a low-voltage, two-stage CMOS op-amp. The concept of PSO is based on communal manner of bird flocking. The disadvantages of PSO are premature convergence and stagnation problem. Simplex-PSO is the combination of Nelder–Mead simplex method and PSO without considering the velocity term. The main idea is to optimize the size of the MOS transistors used for the op-amp circuit to reduce the overall area of the circuit. PSO- and simplex-PSO-based optimized results are confirmed by SPICE-based simulation. SPICE simulation results show that design specifications are approximately met and necessary functionalities are achieved. Simplex-PSO shows the better optimizing efficiency than PSO for the designed circuit.