On the Evolution of Analog Electronic Circuits Using Building Blocks on a CMOS FPTA

This article summarizes two experiments utilizing building blocks to find analog electronic circuits on a CMOS Field Programmable Transistor Array (FPTA). The FPTA features 256 programmable transistors whose channel geometry and routing can be configured to form a large variety of transistor level analog circuits. The transistor cells are either of type PMOS or NMOS and are arranged in a checkerboard pattern. Two case studies focus on improving artificial evolution by using a building block library of four digital gates consisting of a NOR, a NAND, a buffer and an inverter. The methodology is applied to the design of the more complex logic gates XOR and XNOR as well as to the evolution of circuits discriminating between square waves of different frequencies.