Memory device with read-write-read memory controller

A memory device, comprising:

• a memory cell array comprising a plurality of memory cells, each of the plurality of memory cells having a switch element, and a data storage element connected to the switch element and containing a phase-change material;
• and
• a memory controller for obtaining first read voltages from the plurality of memory cells, inputting a first write current to the plurality of memory cells, and then, obtaining second read voltages from the plurality of memory cells, wherein the memory controller compares the first read voltage of a first memory cell of the plurality of memory cells to the second read voltage of the first memory cell to determine a state of the first memory cell,
• wherein the memory controller further comprises:
• a first capacitor for charging electric charges corresponding to the first read voltage;
• a second capacitor for charging electric charges corresponding to the second read voltage;
• and
• a comparator for adding an offset value to a voltage of the first capacitor, and comparing the voltage of the first capacitor to a voltage of the second capacitor,
• wherein the memory controller further comprises:
• a first sense amplifier configured to turn on a first switch for charging the first capacitor when a clamping voltage is applied to detect the first read voltage, and to turn on a second switch for charging the second capacitor when the clamping voltage is applied to detect the second read voltage.