Patent ID: 7477555
Filing Date: 2009-01-13
Classification: G11C

Abstract:
1. A differential fuse sensing system, comprising; a fuse leg configured for introducing a sense current through an electrically programmable fuse (eFUSE) to be sensed; a differential sense amplifier having a first input node coupled to the fuse leg and a second node coupled to a reference voltage; the fuse leg further comprising a current supply device controlled by a variable reference current generator configured to generate an output signal therefrom such that the voltage on the first input node of the sense amplifier is equal to the voltage on the second input node of the sense amplifier whenever the resistance value of the eFUSE is equal to the resistance value of a programmable variable resistance device included within the variable reference current generator; and a first pair of isolation devices configured between the fuse leg and the first input node of the sense amplifier and a second pair of isolation devices configured between the reference voltage and the second input node of the sense amplifier, the first and second pair of isolation devices configured to establish, within the sense amplifiers, voltage difference proportional to the relative difference between the resistance of the eFUSE and a reference resistance defined by the digitally controlled, variable resistance device.