Patent ID: 7203112

Claim:
A method for sensing an output of a predetermined memory cell capable of switching between a high resistance state and a low resistance state, comprising: applying a predefined voltage to the predetermined memory cell to generate an output current reflecting a resistance of the predetermined memory cell, and to one or more reference memory cells to generate a first reference current reflecting the high resistance state, and a second reference current reflecting the low resistance state; providing a first differential value representing the difference between the output current and the first reference current, and a second differential value representing the difference between the output current and second reference current; and comparing the first differential value with the second differential value to generate a digital output representing the resistance state of the predetermined memory cell, wherein the step of providing the first and second differential values further comprises: inputting the first reference current into a first node and a second node of a first differential amplifier; inputting the output current into a first node of a second differential amplifier, and the second reference current into a second node of the second differential amplifier and inputting the second reference current into a first node of a third differential amplifier, and the first reference current into a second node of the third differential amplifier.