Apparatus, devices, systems, and methods are described that include variable state material data storage. Example devices include current compliance circuits that are configured to dynamically adjust a current passing through a variable resistance material during a memory operation. Some configurations utilize components within an array of memory cells to form a current compliance circuit. Additional apparatus, systems, and methods are described.

A detection circuit that can detect a two-terminal memory cell changing state. For example, in response to electrical stimuli, a memory cell will change state, e.g., to a defined higher resistance state or a defined lower resistance state. Other, techniques do not detect this state change until after the stimuli is completed and a subsequent sensing operation (e.g., read pulse) is performed. The detection circuit can detect the state change during application of the electrical stimuli that cause the state change and can do so by comparing the magnitudes or values of two particular current parameters.

A digital-to-analog converter (DAC) and memory device includes an array of memory cells including resistive memory elements programmable between a high resistive and low resistive state. In implementations the array of memory cells is segmented into unary and binary coded sub-arrays. The device includes a binarizer configured to couple to the memory array to assign binary weights, or segmented unary and binary weights, to currents through a plurality of memory cells or voltages across a plurality of memory cells. The memory device further includes a summer to sum the weighted outputs of the binarizer. A current to voltage converter coupled with the summer generates an analog output voltage corresponding with digital data stored in a plurality of memory cells.

Apparatus and methods utilize a replica circuit to generate a voltage for programming of a memory cell, such as a memory cell of a phase-change memory (PCM). Current passing through a circuit including the memory cell to be programmed is mirrored in a scaled or unscaled manner, and provided as an input to the replica circuit. The replica circuit represents voltage drops that should be encountered when programming the memory cell. An input voltage is also provided to the replica circuit, which affects the voltage drop within the replica circuit that represents the voltage drop of the cell. The voltage drop across the replica circuit can then be mirrored and provided to bias the circuit including the memory cell.

A nonvolatile memory apparatus includes a sensing voltage generation unit, a memory cell, a current copy unit and a data sensing unit. The sensing voltage generation unit provides a sensing voltage with a constant level, to a sensing node. The memory cell receives the sensing voltage from the sensing node. The current copy unit generates copied current with substantially the same magnitude as sensing current which flows through the memory cell. The data sensing unit senses the copied current and generates a multi-bit data output signal.

A nonvolatile memory apparatus includes a sensing voltage generation unit, a memory cell, a current copy unit and a data sensing unit. The sensing voltage generation unit provides a sensing voltage with a constant level, to a sensing node. The memory cell receives the sensing voltage from the sensing node. The current copy unit generates copied current with substantially the same magnitude as sensing current which flows through the memory cell. The data sensing unit senses the copied current and generates a multi-bit data to output signal.

Methods, systems and devices are disclosed, such as an electronic device that includes a plurality of data locations and a delta-sigma modulator. In some embodiments, the delta-sigma modulator includes a preamplifier coupled to the data locations and a latch coupled to the preamplifier.

Some embodiments include apparatuses and methods having a first memory element and a first select component coupled to the first memory element, a second memory element and a second select component coupled to the second memory element, and an access line shared by the first and second select components. At least one of the embodiments can include a circuit to generate a signal indicating a state of the second memory element based on a first signal developed from a first signal path through the first memory element and a second signal developed from a second signal path through the second memory element.

A resistive memory device comprising: a memory cell having a programmable resistance representing stored data; and a read circuit configured to be connected to the memory cell via a first signal line and read the stored data, wherein the read circuit includes: a voltage controller configured to control a first voltage of the first signal line to be a constant voltage and output a signal to a sensing node; and a sense amplifier connected to the voltage controller via the sensing node, and configured to compare a sensing voltage of the sensing node with a reference voltage.

A resistive memory device. Implementations may include an array of memory cells including resistive memory elements which are coupled to isolation transistors and which may include a magnetic tunnel junction. A decoder decodes input address information to select a row of the array. A binarizer coupled to the memory array assigns binary weights to outputs of the memory array output through bit lines coupled to the memory cells. A summer sums the binary weighted outputs, and a quantizer generates an output digital code corresponding to data stored in a plurality of memory cells during a prior program cycle. The outputs of the memory array may be currents or voltages. In implementations multiple arrays of memory cells may be utilized and their respective outputs combined to form higher bit outputs, such as eight bit, twelve bit, sixteen bit, and so forth.