US Patent 9287009 Repair circuit and fuse circuit

A repair circuit includes first and second fuse circuits, a determination circuit and an output circuit. The first fuse circuit includes a first fuse and is configured to generate a first master signal indicating whether the first fuse has been programmed. The second fuse circuit includes second fuses and is configured to generate a first address indicating whether each of the second fuses has been programmed. The determination circuit is configured to generate a detection signal based on the first master signal and the first address. The detection signal indicates whether a negative program operation has been performed on the second fuse circuit. The output circuit is configured to generate a second master signal based on the first master signal and the detection signal and generate a repair address corresponding to a defective input address based on the first address and the detection signal.