US Patent 7643336 Phase change memory device

A phase change memory device comprises a cell array unit including a phase change resistance cell disposed in a region where a word line and a bit line are crossed, a sense amplifier configured to sense and amplify data of the phase change resistance cell, a write driving unit configured to supply a write voltage corresponding to data to be written in the cell array unit in response to an enabling signal, and a write verifying control unit controlled by an activation control signal and configured to compare data read through the sense amplifier with the data to be written so as to output the enabling signal.