Design of a New External Signal Controlled Polymorphic Gates

As encountered in electronics systems, a conventional circuit fails in extreme conditions due to changes in transistors characteristics. Engineers are trying to deal with this problem for years until they come up with the adaptive electronics circuit they called polymorphic circuits. Polymorphic circuits are multifunctional in many ways. It has an ability to modify its system and vary with different conditions of environment; this depends on its components response. Its components are transistors combined to form a building block called polymorphic gates that changes its functionality as a response to controls such as temperature, power supply voltage (Vdd), light, an external signal, etc. For example, there is a logic gate that operates as AND when the temperature is 300 K and as OR when the temperature is 398 K. The reconfiguration of the polymorphic system does not depend on modifying the structure, instead on changing the functionality of individual building block. Considering the structure of the circuit, it always remains unchanged which makes it different from the classic reconfiguration process made with electronics system. This paper will design a building block polymorphic gates with the least transistors possible and applies it to a multifunctional two-bit Adder-Subtractor polymorphic circuit. After being applied to a polymorphic circuit, there will be comparisons of two technologies of IC design using Tanner EDA Tools and LT Spice IV.