A New Gate for Optimal Fault Tolerant & Testable Reversible Sequential Circuit Design

With phenomenal growth of high speed and complex computing applications, the design of low power and high speed logic circuits have created tremendous interest. Conventional computing devices are based on irreversible logic and further reduction in power consumption and/or increase in speed appears non-promising. Reversible computing has emerged as a solution looking to the power and speed requirements of future computing devices. In reversible computing logic gates used are such that input can be generated by reversing the operation from output. A number of reversible combinational circuits have been developed but the growth of sequential circuits was not significant due to feedback and fanout was not allowed. However, allowing feedback in space, a very few sequential logic blocks i.e. flip-flops have been reported in literature. In order to develop sequential circuits, flip-flops are used in conventional circuits. Also good circuit design methods, optimized and fault tolerant designs are also needed to build large, complex and reliable circuits in conventional computing. Reversible flip-flops are the basic memory elements that will be the building block of memory for reversible computing and quantum computing devices. In this dissertation we plan to address above issues. First we have proposed a Pareek gate suitable for low-cost flip-flops design and then design methodology to develop flip-flops are illustrated. Further almost all flip-flops and some example circuit have been developed and finally these circuits have been converted into fault tolerant circuits by preserving their parity and designs of offline as well as online testable circuits have been proposed. In this dissertation work, we have also compared quantum cost as well as other parameters with existing circuits and shown a significant improvement in almost all parameters.