A fuse sense circuit has a sense amplifier and a post amplifier (gain
stage). The sense amplifier has a reference branch and one or more sense
(or fuse) branches. The fuse sense circuit determines the state of the
fuses using safe currents and provides much higher gain than prior art.
The post amplifier is a scaled replica of the reference branch or one of
the sense branches in that the devices in the post amplifier maintain the
same ratio as similar devices in the reference branch, and components in
the post amplifier each matches components in the reference branch. The
sense amplifier output is interpreted by the post amplifier's matched
gain stage and has a trip point that sufficiently tracks the reference
voltage. The result is reduced process and voltage sensitivity, which
allows lower differential fuse resistance to be accurately detected with
a non-ideal sense amplifier. Multiple gain stages may be added to
multiple sense branches for redundancy and single-ended sensing.