Current switch for programming vertical fuses of a read only memory

摘要

A ROM having an on-chip current switch is provided that removes the programming voltage from the vertical fuse of the ROM when the fuse is programmed, thereby preventing excessive current from flowing therethrough. A programming current switch is coupled between an output terminal and a row decode for switchable transmitting a programming voltage from the output terminal to the row decode, a word line and a fuse, wherein the programming voltage will program the fuse causing the voltage thereacross to change. A program sense amplifier is coupled between the row decode and the programming current switch for switching the programming current switch off when the voltage change has been sensed.