Patent ID: 8243514

Claim:
A method of operation for a non-volatile memory device including a plurality of memory cells respectively programmed to a first state ideally indicated by a first threshold voltage distribution defined between a first lower read voltage and a first upper read voltage, or a second state ideally indicated by a second threshold voltage distribution, greater than the first threshold voltage distribution and defined between a second lower read voltage and a second upper read voltage, the method comprising: for each one of a plurality of preliminary read voltages in a range extending over at least a portion of a voltage range between the first upper read voltage and the second lower read voltage, applying a preliminary read voltage to read data stored in the plurality of memory cells and provide corresponding output data, and on a basis of the output data, determining a corresponding number of activated memory cells in the plurality of memory cells; selecting one of the plurality of preliminary read voltages resulting in a minimum number of activated memory cells as a read voltage; and then, using the read voltage to discriminate between memory cells programmed to the first state and memory cells programmed to the second state.