Evolution of a Low-Distortion, Low-Bias 60 Decibel Op Amp with Good Frequency Generalization using Genetic Programming
ABSTRACTGenetic programming was used toevolve both the topology and thesizing (numerical values) for eachcomponent of a low-distortion, low-bias 60 decibel (1000-to-1) amplifiercircuit with good frequencygeneralization. The evolved circuitwas composed of two types oftransistors (active elements) as well asresistors and capacitors. 1.Introduction The problem of circuit synthesis involves designing anelectrical circuit that satisfies user-specified design goals. Acomplete design of an electrical circuit includes both itstopology and the sizing of all its components. Thetopology of a circuit consists of the number of componentsin the circuit, the type of each component, and a list of allthe connections between the components. The sizing of acircuit consists of the component value(s) of eachcomponent.Evolvable hardware is one approach to automated circuitsynthesis. Some of the early pioneering work in this fieldincludes that of Higuchi, Niwa, Tanaka, Iba, de Garis, andFuruya (1993), Hemmi, Mizoguchi, and Shimohara (1994);Mizoguchi, Hemmi, and Shimohara (1994); and the workpresented at the 1995 workshop on evolvable hardware inLausanne (Sanchez and Tomassini 1996).The design of analog circuits and mixed analog-digitalcircuits has not proved to be amenable to automation(Rutenbar 1993). In DARWIN (Kruiskamp and Leenaerts1995), a CMOS op amp circuit was evolved using a geneticalgorithm. However, the topology of each op amp was oneof 24 hand-designed topologies. Thompson (1996) used agenetic algorithm to evolve a frequency discriminator on aXilinx 6216 reconfigurable processor in analog mode.