| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide self-adaptive and self-calibrated methods for multilevel (MLC) nonvolatile memories (NVM). <P>SOLUTION: NVM cells are programmed into a fixed response tolerance window centered at a reference current or voltage corresponding to a gate voltage applied to controlled gates. An incremental gate voltage larger than the threshold voltage tolerance window of each cell generates an adaptive output current (voltage) in response to a stepped voltage corresponding to the level of information stored in the cell. The stepped voltage applied to the gate transitions from a voltage just below the threshold voltage of the cell to a voltage corresponding to the threshold voltage of the cell. Thus, an output current from the cell pass the current (voltage) transition in comparison with the reference current (voltage). The transition is detectable, and converted into bit-word information representing the voltage level stored in the cell. When the response of the cell falls outside the response tolerance window into the guard-band regions, the cell is re-calibrated, and the bit-word information is saved from fading away. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
