MULTI LEVEL MEMORY DEVICE AND ITS DATA SENSING METHOD

摘要

According to the present invention, provided is a multi level memory device, in which a continuous flow of a cell current is not required during a detection of data stored in a memory cell, and a more significant bit determination operation of data stored in another memory cell during a determination of a less significant bit of data stored in the memory cell. The multi level memory device according to a first invention of the present invention includes: a more significant bit determination circuit for determining a plurality of more significant bits by comparing a cell current flowing in a memory cell with a predetermined reference current; a current/voltage conversion circuit for converting a copied cell current obtained by copying the cell current into a predetermined cell voltage to store the converted cell voltage; a charging time determination circuit for determining a charging time to convert the copied cell current into the predetermined cell voltage and store the converted cell voltage; and a less significant bit determination circuit for determining a plurality of less significant bits in response to a charging end signal outputted from the charging time determination circuit.