POLY FUSES IN CMOS INTEGRATED CIRCUITS

An integrated circuit fuse with a fuse element having an "open" state and a "closed" state. A fuse status indicator is provided to indicate whether the fuse element is "open" or "closed". A current driver is electrically connected between the fuse element and electrical ground. One input of a dual input multiplexer is electrically connected to the fuse status indicator. The multiplexer's other input receives a fuse status simulation signal. A simulation mode switching signal is applied to the multiplexer's select input. A fuse output signal is consequently provided at the multiplexer's output to simulate operation of the fuse element in either the "open" or the "closed" state. The fuse element can be opened by causing a current having a value exceeding a preselected minimum value to flow through the fuse element for a preselected minimum time. This is preferably accomplished by fabricating the current driver as an NMOS device having a size sufficiently large to conduct the minimum value current for the minimum time required to open the fuse element. Advantageously, a pre-driver is provided to rapidly turn the current driver on, upon receipt of a fuse opening signal.