A low power E-fuse repair methodology substantially removes system latency
during memory and/or E-fuse farm module power-down in a device that
employs E-fuse farm technology. The method maintains power to the repair
registers and minimal control logic in the memories, while all other
circuitry can be either placed in a low power data retention mode, or
completely powered off. There is no need to rescan the repair data from
the E-fuse farm after one or more memories are powered back up. This
provides dynamic power savings since there is no longer any need to idle
the system to reload repair data. Since the E-fuse farm can be powered
down after initial system power-up and repair data is loaded into the
memories, there is also a significant leakage power savings.