Patent ID: 7701226

Claim:
A method for determining a fuse state comprising: providing a fuse that has a resistance which is a first value when unprogrammed, a second value when programmed, and a third value when destroyed, wherein the second value is greater than the first value, and the third value is greater than the second value; determining whether the fuse resistance has the first, second or third values, wherein said determining comprises: generating a first reference voltage drop across a first reference component having a first reference resistance, wherein the first reference resistance is greater than the first value and less than the second value; generating a second reference voltage drop across a second reference component having a second reference resistance, wherein the second reference resistance is greater than the second value and less than the third value; determining a fuse voltage drop across the fuse; and determining that the fuse resistance has the first value when the fuse voltage drop is less than the first reference voltage drop. has the second value when the fuse voltage drop is greater than the first reference voltage drop and less than the second reference voltage drop, and has the third value when the fuse voltage drop is greater than the second reference voltage drop, generating a fuse read signal that is deasserted when the fuse resistance is the first value and is asserted otherwise; and generating a fuse fail signal that is asserted when the fuse resistance is greater than the third value and is deasserted otherwise.