US Patent 7196570 Multiple-time programmable resistance circuit

Fuse circuit designs and the use thereof are disclosed. In one example, a fuse circuit providing predictable total resistances for multiple rounds of programming comprises a predetermined number of fuse stages coupled in series. Each stage comprises a first and a second connecting nodes, a fuse connected between the first and second connecting nodes, a first resistor with its first end connected to the first connecting node, and a second resistor with its first end connected to the second connecting node, wherein the first and second resistors connect to a third and a fourth connecting nodes, which are the first and second connecting nodes of a next fuse stage respectively, through their second ends.