Method and apparatus managing worn cells in resistive memories
AssigneeSamsung Electronics Co., Ltd.
InventorYong-hoon KANG
Life of this patent
Estimating the term…
Abstract
A method and apparatus for management worn resistive memory cells are presented. A normal read mode or worn memory cell detecting mode are used depending on the wear state of a resistive memory cell. A detection reference point is changed upon wear indication to detect the resistance of the resistive memory cell. The resistance of the resistive memory cell is detected using the changed detection reference point to determine whether or not the resistive memory cell is worn by comparing the detected resistance to a wear reference level.
Claims20
A method of managing worn memory cells in a resistive memory, the method comprising:
- switching from a normal read mode to a worn memory cell detecting mode upon detecting a decrease in a resistance of a resistive memory cell;
- changing a detection reference point used to detect the resistance of the resistive memory cell when switching to the worn memory cell detecting mode;
- and
- detecting the resistance of the resistive memory cell using the changed detection reference point to determine whether or not the resistive memory cell is worn by comparing the detected resistance to a wear reference level.
A worn memory cell management apparatus operating in conjunction with a sense amplifier detecting a programmed state for a resistive memory cell using a reference signal, the apparatus comprising:
- a mode changing unit configured to switch between a normal read mode and a worn memory cell detecting mode and provide a mode change signal;
- a reference control unit that, upon receiving the mode change signal indicating a switch from the normal read mode to the worn memory cell detecting mode, changes a detection reference point used to detect a resistance of the resistive memory cell and provides an adjusted reference signal to the sense amplifier;
- and
- a cell wear determining unit configured to detect the resistance of the resistive memory cell at the changed detection reference point and determine whether the resistive memory cell is worn by comparing the detected resistance of the resistive memory cell to a wear reference level.
A method of operating a memory system having a memory cell array including a resistive memory cell, the method comprising:
- during a normal read mode, providing a sense amplifier with an input voltage and a reference voltage to detect a programmed state for the resistive memory cell in relation to a detection reference point used to discriminate between adjacent resistance distributions for the resistive memory cell, wherein the input voltage is determined by an applied bias voltage;
- and
- during a worn memory cell detecting mode executed to determine whether the resistive memory cell is worn, providing the sense amplifier with at least one of an adjusted reference voltage and an adjusted input voltage to change the detection reference point.
Dependencies are inferred from the claim text.