Permanent Fault Repair for FPGAs with Limited Redundant Area

FPGA fault repair schemes remove faulty elements from designs through reconfiguration. In designs with high FPGA utilization, a sufficient number of routable faultfree elements may not be available for permanent fault repair. We present a new permanent fault repair scheme, in which the original design is reconfigured into another fault tolerant design that has smaller area, so the damaged element can be avoided. Three new schemes that fully utilize available fault-free area and provide low impact on availability are presented. Analytical results show that our schemes improve availability compared to a module removal approach, which removes a redundant module when it becomes faulty.