Patent attributes
A technique for performing read operations with reduced errors in a memory device such as flash memory. An automatic gain control approach is used in which cells which have experienced data retention loss are read by a fine M-level quantizer which uses M−1 read threshold voltage levels. In one approach, M-quantized threshold voltage values are multiplied by a gain to obtain gain-adjusted threshold voltage values, which are quantized by an L-level quantizer, where L<M, by comparing the gain-adjusted threshold voltage values to read threshold voltage levels of a fresh memory device. In another approach, the read threshold voltage levels of the fresh device are gain adjusted for reading non-gain-adjusted threshold voltage values from the cells which have experienced data retention loss.
