Patent ID: 11875850
Assignee: MACRONIX INTERNATIONAL CO., LTD.
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 0:
1. A content addressable memory (CAM) memory device, comprising:
a plurality of CAM memory strings; and
an electrical characteristic detection circuit coupled to the CAM memory strings;
wherein
in data searching, a search data is compared with a storage data stored in the CAM memory strings, the CAM memory strings generate a plurality of memory string currents, the electrical characteristic detection circuit detects the memory string currents to generate a plurality of sensing results, or the electrical characteristic detection circuit detects a plurality of match line voltages on a plurality of match lines coupled to the CAM memory string to generate the plurality of search results;
the storage data and the search data is a range storage data and a single-bit search data, or the storage data and the search data is a single-bit storage data and a range search data,
a CAM memory cell of the CAM memory string includes N1 memory cells (N1 being a positive integer larger than or equal to 3), when the CAM memory cell is encoded for storing M1 decimal data combinations (wherein M1 being a positive integer, M1 >1 and M1<N1), M1 memory cells of the memory cells are programmed to have a first threshold voltage, and (N1-M1) memory cells of the memory cells are programmed to have a second threshold voltage; and
the search data is defined by N2 search voltages (N2 being a positive integer larger than or equal to 3), when the search data is encoded for M2 decimal data combinations (wherein M2 being a positive integer, M2≥1 and M2≤N2), M2 search voltages of the search voltages have a first search voltage, and (N2−M2) search voltages of the search voltages have a second search voltage.