A three-dimensional memory array may include a first memory array and a second memory array, stacked above the first. Some memory cells of the first array may be coupled to a first layer selector transistor, while some memory cells of the second array may be coupled to a second layer selector transistor. The first and second layer selector transistor may be coupled to one another and to a peripheral circuit that controls operation of the first and/or second memory arrays. A different layer selector transistor may be used for each row of memory cells of a given memory array and/or for each column of memory cells of a given memory array. Such designs may allow increasing density of memory cells in a memory array having a given footprint area, or, conversely, reducing the footprint area of the memory array with a given memory cell density.

A memory circuit includes: memory cells each including a storage transistor corresponding to a predetermined configuration; and a tracking circuit configured to elapse a variable waiting period during which a voltage on a first node decreases from a first level to a second level, the tracking circuit including a first finger circuit coupled between a first node of a tracking bit line and a reference voltage node, the first finger circuit including a first set of first tracking cells, each first tracking cell including a first shadow transistor corresponding to the predetermined configuration, gate terminals of the first shadow transistors being coupled with a tracking word line; and a second finger circuit coupled between the first node and the reference voltage node; and a first switch configured to adjust the variable waiting period by selectively coupling the second finger circuit in parallel with the first finger circuit.

The present disclosure relates to circuits, systems, and methods of operation for a memory device. In an example, a memory device includes a plurality of memory cells, each memory cell having a variable impedance that varies in accordance with a respective data value stored therein; and a read circuit configured to read the data value stored within a selected memory cell based upon a variable time delay determination of a signal node voltage change corresponding to the variable impedance of the selected memory cell.

The present disclosure relates to circuits, systems, and methods of operation for a memory device. In an example, a memory device includes a plurality of memory cells, each memory cell having a variable impedance that varies in accordance with a respective data value stored therein; and a read circuit configured to read the data value stored within a selected memory cell based upon a variable time delay determination of a signal node voltage change corresponding to the variable impedance of the selected memory cell.

A counter can have a number of sensing components. Each respective sensing component can be configured to sense a respective event and can include a respective first capacitor configured to be selectively coupled to a second capacitor in response to the respective sensing component sensing the respective event. The second capacitor can be configured to be charged to a voltage by each respective first capacitor that is selectively coupled to the second capacitor. The counter can have a comparator with a first input coupled to the second capacitor and a second input coupled to a reference voltage corresponding to a threshold quantity of events. The comparator can be configured to output a signal indicative of the threshold quantity of events being sensed in response to the voltage of the second capacitor being greater than or equal to the reference voltage.

A memory circuit includes: memory cells each including a storage transistor having a first configuration; and a tracking circuit including: a tracking bit line having first and second intermediary nodes; a tracking word line; a first finger circuit (coupled between the first intermediary node and a reference voltage node) including: a first set of first tracking cells, each including a first shadow transistor having the first configuration; and a second finger circuit (coupled between the second intermediary node and the reference voltage node) including: a second set of second tracking cells, each including a second shadow transistor having the first configuration; gate terminals of the first and second shadow transistors being coupled with the tracking word line; and a switch configured to selectively couple the first intermediary node with the second intermediary node and thereby selectively couple the first and second finger circuits in parallel.

A compute-in-memory bitcell is provided that includes a pair of cross-coupled inverter for storing a stored bit. The compute-in-memory bitcell includes a logic gate for multiplying the stored bit with an input vector bit. An output node for the logic gate connects to a second plate of a positive capacitor. A first plate of the positive capacitor connects to a positive read bit line. An inverter inverts a voltage of the second plate of the positive capacitor to drive a first plate of a negative capacitor having a second plate connected to a negative read bit line.

A three-dimensional memory array may include a first memory array and a second memory array, stacked above the first. Some memory cells of the first array may be coupled to a first layer selector transistor, while some memory cells of the second array may be coupled to a second layer selector transistor. The first and second layer selector transistor may be coupled to one another and to a peripheral circuit that controls operation of the first and/or second memory arrays. A different layer selector transistor may be used for each row of memory cells of a given memory array and/or for each column of memory cells of a given memory array. Such designs may allow increasing density of memory cells in a memory array having a given footprint area, or, conversely, reducing the footprint area of the memory array with a given memory cell density.

A counter can have a number of sensing components. Each respective sensing component can be configured to sense a respective event and can include a respective first capacitor configured to be selectively coupled to a second capacitor in response to the respective sensing component sensing the respective event. The second capacitor can be configured to be charged to a voltage by each respective first capacitor that is selectively coupled to the second capacitor. The counter can have a comparator with a first input coupled to the second capacitor and a second input coupled to a reference voltage corresponding to a threshold quantity of events. The comparator can be configured to output a signal indicative of the threshold quantity of events being sensed in response to the voltage of the second capacitor being greater than or equal to the reference voltage.

The present disclosure relates to circuits, systems, and methods of operation for a memory device. In an example, a memory device includes a memory array including a plurality of memory cells, each memory cell having an impedance that varies in accordance with a respective data value stored therein; and a tracking memory cell having an impedance based on a tracking data value stored therein; and a read circuit coupled to the memory array, the read circuit configured to determine an impedance of a selected memory cells with respect to the impedance of the tracking memory cell; read a data value stored within the selected memory cell based upon a voltage change of a signal node voltage corresponding to the impedance of the selected memory cell.