Technologies for various memory structures for artificial intelligence (AI) applications and methods thereof are described. An XNOR circuit along with a sense amplifier may be combined with an array (or multiple arrays) of memory such as non-volatile memory (NVM) or an NVM, SRAM combination to perform an XNOR operation on the data read from the memory. Various versions may include different connections allowing simplification of circuitry or timing. In some examples, memory array may include programmable resistor/switch device combinations, or multiple columns connected to a single XNOR+SA circuit.

A memory device includes a memory cell and a sense amplifier. The sense amplifier has a reference circuit configured to output a reference voltage and a sensing circuit connected to the memory cell. A comparator includes a first input and a second input, with the first input connected to the reference circuit to receive the reference voltage, and the second input connected to the memory cell. A precharger is configured to selectively precharge the sensing circuit to a predetermined precharge voltage.

A read-write circuit mainly includes a read circuit and a write circuit. The write circuit comprises: a first voltage selector and a first voltage follower circuit that is electrically connected to the memristor storage array. The read-write circuit further includes a second voltage selector and a second voltage follower circuit that is electrically connected to the memristor storage array. Voltage stable following during bipolar writing is selected through the foregoing selector. Meanwhile, the reading circuit is provided with a variable resistor to select an access mode. The actual read-out voltage and the output voltage passing through the reference resistor under the same read voltage are input into a differential amplifier to obtain read-out data.

A self-biased sense amplification circuit includes a local bit line, a reset unit, a main bit lie, a pre-amplifier, a data line, a sample reference unit, and a sense amplifier. The local bit line receives a cell current generated by a memory cell during a sense operation. The reset unit resets the local bit line to a first system voltage during a sample operation. The pre-amplifier generates a read current on the main bit line according to a voltage of the local bit line during the sample operation and the sense operation. The data line is coupled to the main bit line. The sample reference unit generates a first reference current and a second reference current during the sample operation, and generates the first reference current during the sense operation. The sense amplifier senses a voltage of the data line.

Apparatuses and methods for sensing a resistance variable memory cell include circuitry to apply a programming signal to a memory cell in the array, the programming signal associated with programming resistance variable memory cells to a particular data state, and detect a change in resistance of the memory cell to determine if a data state of the memory cell changes from an initial data state to a different data state during application of the programming signal.

Numerous embodiments of circuitry for a set-while-verify operation and a reset-while verify operation for resistive random access memory cells are disclosed. In one embodiment, a set-while-verify circuit for performing a set operation on a selected RRAM cell in the array applies a combination of voltages or current to a bit line, word line, and source line associated with the selected RRAM cell and stops said applying when the set operation is complete. In another embodiment, a reset-while-verify circuit for performing a reset operation on a selected RRAM cell in the array applies a combination of voltages or current to a bit line, word line, and source line associated with the selected RRAM cell and stops said applying when the reset operation is complete.

An embodiment voltage generation circuit, for a memory having a memory array with a plurality of memory cells coupled to respective wordlines and local bit-lines, each having a storage element and selector element, a bipolar transistor being coupled to the storage element for selective flow of a cell current during reading or verifying operations, and a base terminal of the selector element being coupled to a respective wordline; associated to each bit-line is a biasing transistor having a control terminal, and the circuit generates a cascode voltage for this control terminal; a driver stage is coupled to one end of each wordline. The circuit generates the cascode voltage based on a reference voltage, which is a function of the emulation of a voltage drop on the driver stage, on the wordline, and on the memory cell as a result of a current associated to the corresponding selector element.

A sense amplifier and a method for accessing a memory device are disclosed. In an embodiment a sense amplifier for a memory device includes a first input node selectively coupled to a first memory cell through a first local bitline and a first main bitline, a second input node selectively coupled through a second local bitline and a second main bitline to a second memory cell or to a reference generator configured to generate a reference current, a first current generator controllable so as to inject a first variable current into the first input node, a second current generator controllable so as to inject a second variable current into the second input node, a first branch coupled to the first input node and comprising a first switch circuit, a first sense transistor and a first forcing transistor and a second branch coupled to the second input node and including a second switch circuit, a second sense transistor and a second forcing transistor.

A method for programming a phase-change-memory device of a differential type comprises, in a first programming mode, supplying, during a first time interval, a same first programming current, of a type chosen between a SET current and a RESET current, to all the direct and complementary memory cells that are to be programmed with said first programming current; and, in a second programming mode, supplying, during a second time interval, a same second programming current, of the other type chosen between a SET current and a RESET current, to all the direct and complementary memory cells that are to be programmed with said second programming current, thus completing, in just two time steps, writing of a logic word in the memory device.

A self-biased sense amplification circuit includes a local bit line, a reset unit, a main bit lie, a pre-amplifier, a data line, a sample reference unit, and a sense amplifier. The local bit line receives a cell current generated by a memory cell during a sense operation. The reset unit resets the local bit line to a first system voltage during a sample operation. The pre-amplifier generates a read current on the main bit line according to a voltage of the local bit line during the sample operation and the sense operation. The data line is coupled to the main bit line. The sample reference unit generates a first reference current and a second reference current during the sample operation, and generates the first reference current during the sense operation. The sense amplifier senses a voltage of the data line.