CMOS analog amplifier circuit sizing using opposition based harmony search algorithm

An optimum design of analog CMOS differential amplifier (Diff-Amp) with current mirror load has been presented in this paper. An evolutionary optimization technique called Opposition based Harmony Search Algorithm (OHS) is employed to minimize the total MOSFET area of the designed circuit. The novel Harmony Search (HS) algorithm is selected as the parent and the opposition based approach is employed to it with an intention to exhibit accelerated near-global convergence profile. At the initialization stage, for choosing the randomly generated population/solutions, opposite solutions are also considered and the fitter one is selected as apriori guess. This causes faster convergence profile. Each solution in Harmony Memory (HM) is generated on the basis of memory consideration rule, a pitch adjustment rule and a re-initialization process which gives the optimum result corresponding to the least error fitness in multidimensional search space. Differential Evolution (DE), Harmony Search (HS), Artificial Bee Colony (ABC) and Particle Swarm Optimization (PSO) have an inbuilt disadvantage of early convergence and stagnation problem. But in OHS optimization technique has overcome these shortcomings. The optimally designed differential amplifier circuit occupies the least total MOS area, and shows the best design conditions like gain, power dissipation etc., in comparison with the formerly reported literature.