Self-Repairing Hybrid Adder with Hot-Standby Topology Using Fault-Localization

Effective self-repairing can be achieved if the fault along with its exact location can be determined. In this paper, a self-repairing hybrid adder is proposed with fault localization. It uses the advantages of ripple carry adder and carry-select adder to reduce the delay and area overhead. The proposed adder reduces the transistor count by 115% to 76.76% as compared to the existing self-checking carry-select adders. Moreover, the proposed design can detect and localize multiple faults. The fault-recovery is achieved by using the hot-standby approach in which the faulty module is replaced by a functioning module at run-time. In case of 3 consecutive faults, the probability of fault recovery has been found to be 96.1% for a 64-bit adder with 8 blocks, where each block has 9 full adders.