Design of optimal CMOS ring oscillator using an intelligent optimization tool

Abstract

This paper presents an intelligent sizing method to improve the performance and efficiency of a CMOS ring oscillator (RO). The proposed approach is based on the simultaneous utilization of powerful and new multi-objective optimization techniques along with a circuit simulator under a data link. The proposed optimizing tool creates a perfect trade-off between the contradictory objective functions in CMOS RO optimal design. This tool is applied for intelligent estimation of the circuit parameters (channel width of transistors), which have a decisive influence on RO specifications. Along the optimal RO design in an specified range of oscillation frequency, the Power Consumption, Phase Noise, Figure of Merit, Integration Index, Design Cycle Time are considered as objective functions. Also, in generation of Pareto front some important issues, i.e., Overall Nondominated Vector Generation, and Spacing are considered for more effectiveness of the obtained feasible solutions in application. Four optimization algorithms called Multi-Objective Genetic Algorithm, Multi-Objective Inclined Planes system Optimization, Multi-Objective Particle Swarm Optimization and Multi-Objective Modified Inclined Planes System Optimization (MOMIPO) are utilized for 0.18-mm CMOS technology with supply voltage of 1-V. Based on our extensive simulations and experimental results MOMIPO outperforms the best performance among other multi-objective algorithms in presented RO designing tool.