E/P durability by using a sub-range of a full programming range
AssigneeLink—A—Media Devices Corporation
InventorsKwok W. Yeung, Meng-Kun Lee
Life of this patent
Estimating the term…
Abstract
A NAND flash memory system is controlled by determining whether to change a value of a voltage threshold. The voltage threshold is associated with an erase operation to a portion of a NAND flash memory chip. In the event it is determined to change the value of the voltage threshold, the value of the voltage threshold is changed and the changed value of the voltage threshold and an identifier associated with the portion of the NAND flash memory chip is stored.
Claims30
A NAND flash memory system, comprising:
- a controller configured to:
- determine whether to change a value of a voltage threshold, wherein the voltage threshold is used to determine whether an erase operation is successful by comparing (1) a voltage stored in a portion of a NAND flash memory chip after an erase attempt with (2) the voltage threshold;
- and
- in the event it is determined to change the value of the voltage threshold:
- change the value of the voltage threshold such that the range of voltages that correspond to a successful erase operation is changed;
- and
- store the changed value of the voltage threshold and an identifier associated with the portion of the NAND flash memory chip;
- and
- the NAND flash memory chip.
A method for controlling a NAND flash memory system, comprising:
- using a processor to determine whether to change a value of a voltage threshold, wherein the voltage threshold is used to determine whether an erase operation is successful by comparing (1) a voltage stored in a portion of a NAND flash memory chip after an erase attempt with (2) the voltage threshold;
- and
- in the event it is determined to change the value of the voltage threshold:
- using the processor to change the value of the voltage threshold such that the range of voltages that correspond to a successful erase operation is changed;
- and
- storing the changed value of the voltage threshold and an identifier associated with the portion of the NAND flash memory chip.
A computer program product for controlling a NAND flash memory system, the computer program product being embodied in a computer readable storage medium and comprising computer instructions for:
- determining whether to change a value of a voltage threshold, wherein the voltage threshold is used to determine whether an erase operation is successful by comparing (1) a voltage stored in a portion of a NAND flash memory chip after an erase attempt with (2) the voltage threshold;
- and
- in the event it is determined to change the value of the voltage threshold:
- changing the value of the voltage threshold such that the range of voltages that correspond to a successful erase operation is changed;
- and
- storing the changed value of the voltage threshold and an identifier associated with the portion of the NAND flash memory chip.
Dependencies are inferred from the claim text.