Image Number 2 for United States Patent #8143902.
An eFuse with at least one fuse unit is provided. The fuse unit includes a common node, a sensing unit with a first input terminal and a second input terminal, at least one fuse coupled between the common node and the first input terminal of the sensing unit with a resistance, and a switching unit coupled between the common node and the second input terminal of the sensing unit. A resistance of the switching unit is equivalent to a first resistance in a normal mode and equivalent to a second resistance in a test mode, and the second resistance is higher than the first resistance. The sensing unit generates an output signal indicating whether the fuse is blown or not according to the resistances of the fuse and the switching unit.