NAND/NOR Gate Polymorphism in Low Temperature Environment

The fundamental aspect behind this paper is focused on behaviour of polymorphic digital circuits in potentially harsh operating environment. Unlike conventional CMOS-based circuits, the area of polymorphic electronics takes and an advantage of inherently built-in features that open up the possibility for on-the-fly adjustment of a particular circuit function with respect to the surrounding environment. The most prevalent benefit here is connected with the fact that space-efficient circuit implementation can be achieved due to the adoption of polymorphic principles and, thus, eliminate the need for an additional function change controller. From a conceptual point of view, key attention is given to a set of experiments which were conducted with the aim to evaluate the influence of wide temperature range (with special interest in low temperatures domain) in case of reconfigurable chip with dedicated polymorphic gates. The experimental setup was based around reconfigurable polymorphic chip REPOMO32, which is primarily designed to be configured (in addition to the configuration bit stream) by means of using the level of power supply voltage (Vdd), and carrier board with all necessary capabilities for temperature measurement up to -40C below zero boundary and its response analysis. Experiments clearly indicate that polymorphic gates in the chip can be easily controlled (in terms of functionality) not only by Vdd, but also by temperature within operating environment. The obtained results also prove that the physical design of the REPOMO32 chip is robust enough under wide range of operating temperature, the chip can also be used for future designs of digital polymorphic circuits controlled by temperature.