Patent ID: 8050129

Claim:
An electrically programmable fuse (e-fuse) apparatus, comprising: an e-fuse macro, disposed in an integrated circuit and comprising a plurality of e-fuse units; and a switch device, disposed in the integrated circuit and having an output node coupled to the e-fuse units and a first input node coupled to a first power source which supplies a first reference voltage acting as a programming voltage of the e-fuse macro, wherein the switch device connects the first power source to the e-fuse units when the e-fuse macro is operated under a programming mode; the first power source is inside the integrated circuit; the e-fuse macro has a power connection node coupled to the output node of the switch device and configured to receive the first reference voltage; when the e-fuse macro is operated under the programming mode, the switch device connects the first input node to the power connection node; and when the e-fuse macro is operated under a read mode to output stored bits, the switch device disconnects the first input node from the power connection node to float the power connection node such that no reference voltage external to the e-fuse macro is supplied to the e-fuse macro via the power connection node.