Patent ID: 8630136

Claim:
A semiconductor memory comprising: a first memory cell including: a first resistance change element having a first end connected to a first bit line, and a first select transistor that is connected between a second end of the first resistance change element and a first voltage terminal and has a gate connected to a first word line; a second memory cell including: a second select transistor having a first end connected to a second bit line and a gate connected to the first word line, and a second resistance change element that has a first end connected to a second end of the second select transistor and a second end connected to a second voltage terminal; a third memory cell including: a third select transistor that has a first end connected to a third bit line and a gate connected to a second word line, and a third resistance change element that has a first end connected to a second end of the third select transistor and a second end connected to a third voltage terminal, the third memory cell acting as a reference cell; a fourth memory cell including: a fourth resistance change element having a first end connected to a fourth bit line, and a fourth select transistor that is connected between a second end of the fourth resistance change element and a fourth voltage terminal and has a gate connected to the second word line, the fourth memory cell acting as a reference cell; a first potential control circuit connected between the third bit line and the fourth bit line to equalize a potential of the third bit line and a potential of the fourth bit line during a reading operation; a first sense amplifier including a first input terminal connected to a first end of the first bit line and a second input terminal connected to a first end of the third bit line, the first sense amplifier being configured to compare a current passing through a first end of the first bit line and a current passing through the first end of the third bit line during the reading operation and output a reading signal corresponding to a comparison result; and a second sense amplifier including a third input terminal connected to a first end of the second bit line and a fourth input terminal connected to a first end of the fourth bit line, the second sense amplifier being configured to compare a current passing through the first end of the second bit line and a current passing through the first end of the fourth bit line during the reading operation and output a reading signal corresponding to a comparison result.