Application of improved PSO for optimal design of CMOS two-stage Op-amp using nulling resistor compensation circuit

In this paper, design of an analog VLSI circuit is proposed using an evolutionary optimization technique. Here, CMOS two-stage op-amp using nulling resistor compensation circuit is considered for the optimal design by utilizing an improved form of Particle Swarm Optimization (PSO) method that is Craziness based Particle Swarm Optimization (CRPSO). The concept of PSO is simple and it replicates the nature of bird flocking. As compared to Genetic algorithm (GA), PSO deals with less mathematical operators. Premature convergence and stagnation problem are the two major limitations of PSO technique. PSO has been already been improved to CRPSO to eliminate the limitations of PSO and is now applied for the optimal design of analog VLSI circuit in this paper. Control parameters of CRPSO are nearly robust and it produces near-global convergence. In this work, CRPSO is used to optimize the sizes of the MOS transistors' to minimize the overall area occupied by the circuit. The results obtained from CRPSO technique are validated with SPICE. SPICE based simulation results show that CRPSO is much better technique than previously reported techniques for the design of above mentioned circuit in terms of MOS area, gain, power dissipation etc.