Differential vector storage for dynamic random access memory

摘要

A storage device stores data in groups of memory cells using vectors corresponding to voltage code codewords, each codeword having k entries. Entries have values selected from a set of at least three entry values and 2n distinct inputs can be encoded into k-entry codewords for some n>k. A vector storage element comprising k cells can store an k electrical quantities (voltage, current, etc.) corresponding to a codeword. The voltage code is such that, for at least one position of a vector, there are at least three vectors having distinct entry values at that position and, for at least a subset of the possible codewords, the sum of the entry values over the positions of each vector is constant from vector to vector in that subset. The storage device might be an integrated circuit device, a discrete memory device, or a device having embedded memory.

主权项

1. An apparatus comprising:
a memory area comprising a plurality of cell groups of k memory cells in each cell group, wherein k is an integer greater than one; a row and column decoder circuit coupled to the memory area and configured to select at least one cell group; a storage data encoder circuit configured to encode an n-bit value, for an n>k, received at a data input into a k-entry codeword of a voltage code, the k-entry codeword representing (i) a selection of a first permutation vector based on a first half of the n-bit value and a second permutation vector based on a second half of the n-bit value, wherein the first and second permutation vectors are weighted with first and second weights, respectively, and (ii) an element-by-element summation of the first and second permutation vectors, wherein each entry in the k-entry codeword is one of three possible entry values; and a cell-load unit configured to store the k-entry codeword as levels in the at least one selected cell group.