Memristor-based multilevel memory

A method to utilize the memristor as a multilevel memory has been proposed. There are several roadblocks in the practical use of memristors for multilevel memory. A difficulty comes from the nonlinearity in the ¿ vs. q curve which makes it difficult to determine the proper pulse width for desired resistance values. Another one comes from the property of the memristor which integrates any kind of signals including noise that appeared at the memristor and causes memristors to be perturbed from their original values. The proposed method enables the memristor to be used as multilevel memory using a reference resistance array by forcing the memristor to stick at a set of predetermined fixed reference resistance values. We propose the write-in (programming) circuit and the readout/restoration circuit which share the information storing technique using the reference resistance array.