Table-based reference voltage characterization scheme
View Patent ↗Method and apparatus for reading data from a non-volatile memory cell, such as a modified STRAM cell. In some embodiments, at least a first and second memory cell are read for a plurality of resistance values that are used to select and store a voltage reference for each memory cell.
1. A method comprising:
reading a plurality of resistance values for at least a first and second memory cell;
determining a voltage reference for each memory cell from the resistance values; and
storing each voltage reference for at least the first and second memory cells in a table on-chip that characterizes at least two memory blocks of different sizes based on the selected voltage reference.
2. The method of claim 1 , wherein at least one memory block undergoes a sub-partition process.
3. The method of claim 1 , wherein the voltage reference is selected and stored for each memory cell at an initial power up stage of the memory cells.
4. The method of claim 3 , wherein the voltage reference for at least one memory cell is recalled after deactivation and subsequent initiation of the memory cells.
5. The method of claim 1 , wherein the voltage reference is selected from a first distribution based on a first resistance and a second distribution based on a second resistance.
6. The method of claim 1 , wherein the voltage reference is selected from a distribution that comprises both an increasing and decreasing range of potential voltage references.
7. The method of claim 1 , wherein the plurality of memory cells are each characterized as a resistive random access memory (RRAM) cell.
8. The method of claim 1 , wherein the plurality of memory cells are each characterized as a spin-torque transfer random access memory (STRAM) cell.
9. An apparatus, comprising:
a memory array comprising a plurality of memory cells;
a control circuit configured to read a plurality of resistance values for at least a first and second memory cell in the memory array, select a voltage reference for each memory cell from the resistance values, and store each voltage reference for at least the first and second memory cells in a table on-chip that characterizes at least two memory blocks of different sizes based on the selected voltage reference.
10. The apparatus of claim 9 , wherein at least one memory block undergoes a sub-partition process.
11. The apparatus of claim 9 , wherein the voltage reference is selected and stored for each memory cell at an initial power up stage of the memory cells.
12. The apparatus of claim 11 , wherein the voltage reference for at least one memory cell is recalled after deactivation and subsequent initiation of the memory cells.
13. The apparatus of claim 9 , wherein the voltage reference is selected from a first distribution based on a first resistance and a second distribution based on a second resistance.
14. The apparatus of claim 9 , wherein the voltage reference is selected from a distribution that comprises both an increasing and decreasing range of potential voltage references.
15. The apparatus of claim 9 , wherein the plurality of memory cells are each characterized as a resistive random access memory (RRAM) cell.
16. The apparatus of claim 9 , wherein the plurality of memory cells are each characterized as a spin-torque transfer random access memory (STRAM) cell.