Multiple-valued content-addressable memory using logic-value conversion and threshold functions

This paper presents a high-density multiple-valued content-addressable memory (MVCAM) for many applications such as database systems and pattern recognition. The basic search operations executed in an MVCAM are both the threshold operations in each cell and logic-value conversion against a multiple-valued input data. Various multiple-valued operations for data retrieval can be easily performed by programming logic-value conversion. Moreover, the cell circuit can be implemented using two transistors and one capacitor. The cell circuit is used not only to store multi-level charge but also to execute sum calculation by the capacitive coupling technique. As a result, the cell circuit is very simple and the chip area of the cell circuit can be reduced to 54% in comparison with that of the equivalent binary implementation.