New tile-based circuits converting BCD code to gray, excess-3, and aiken codes in quantum-dot cellular automata (QCA) nanotechnology

The development of new methods and technologies for improving the stability and reducing the power consumption of electronic devices is a crucial area of research. Quantum-dot Cellular Automata (QCA) has emerged as a promising alternative to the traditional Complementary Metal-Oxide-Semiconductor (CMOS) technology, offering superior optimization in terms of physical size and energy efficiency. This paper introduces three novel digital code converters, designed using the tile-based approach to simplify circuit implementation and enhance integration through optimized majority and inverter gate structures. The proposed converters include: (1) a BCD to gray code converter with 127 cells, 0.18 μm² occupied area, 3 clock phases, and zero NOT gate achieving a 7.3 % and 100 % reduction in the number of cells and NOT gates, respectively, compared to the most similar design; (2) a BCD to excess-3 code converter with 190 cells, 0.25 μm² occupied area, 7 clock phases, and 3 NOT gates, showing a 0.5 %, 13.8 %, 41.7 %, and 25 % reduction in cells, area, used clock phases, and NOT gates, respectively, compared to the closest alternative; and (3) a BCD to aiken (2421) code converter with 287 cells, 0.22 μm² occupied area, zero NOT gate, and 5 clock phases. The energy dissipation for these converters is measured at 55.3 meV, 53.7 meV, and 102 meV, respectively. Simulations are performed using QCADesigner-E version 2.2, validating the functionality and performance of the designs. These results demonstrate the potential of the proposed converters to offer efficient, compact, and low-power solutions for digital systems.