Charge-domain sensing architectures for content-addressable memory

A method for performing content-addressable memory operations, comprising:

• storing data in a plurality of memory cells, each memory cell comprising a programmable switching device and at least one capacitor;
• applying search signals to control terminals of the programmable switching devices representing a query;
• during a search operation, conditionally enabling charge transfer between the capacitors and a match line based on both stored states of the programmable switching devices and the applied search signals;
• placing the match line in a floating condition following the charge transfer to permit intentional charge redistribution associated with the memory cells;
• and
• determining a correspondence between the stored data and the query based on a charge-related characteristic of the match line resulting from the intentional charge redistribution, wherein the determining is performed independently of a magnitude of current conducted by the programmable switching devices.

A ternary content-addressable memory device, comprising:

• a memory cell array including a plurality of memory cells, each memory cell comprising a programmable switching device configured to store data in a plurality of states and at least one capacitor;
• one or more search lines coupled to the programmable switching devices;
• a match line coupled to the memory cells and configured to be selectively floated;
• and
• a sensing circuit coupled to the match line and configured to detect charge redistribution on the match line resulting from conditional charge transfer from the capacitors during a search operation,
• wherein match or mismatch between stored data and applied search signals is determined based on charge-domain sensing rather than a magnitude of current through the programmable switching devices.