Micron Technology Incorporated

John Christopher Sancon

Kang-Yong Kim

Yang Lu

Hyun Yoo Lee

Mingdong Cui

Joemar Sinipete

Mark K Hadrick

Francesco Douglas Verna-Ketel

Smruti Subhash Jhaveri

Yu-Sheng Hsu

Creston M Dupree

Described apparatuses and methods relate to a bank-level self-refresh for a memory system. A memory device can include a controller with logic that implements self-refresh operations in the memory device. The logic may perform self-refresh operations on a set of banks of the memory device that is less than all banks within the memory device. The set of banks of the memory device may be determined such that the peak current in a power distribution network of the memory device is bounded when the self-refresh operation is performed. Accordingly, bank-level self-refresh can reduce a cost of the memory device of a memory system by enabling use of a less complicated power distribution network. The bank-level self-refresh may also be implemented with different types of refresh operations. Amongst other scenarios, bank-level self-refresh can be deployed in memory-expansion environments.

Bank-level self-refresh

Described apparatuses and methods relate to a bank-level self-refresh for a memory system. A memory device can include logic that implements self-refresh operations in the memory device. The logic may perform self-refresh operations on a set of banks of the memory device that is less than all banks within the memory device. The set of banks of the memory device may be determined such that the peak current in a power distribution network of the memory device is bounded when the self-refresh operation is performed. Accordingly, bank-level self-refresh can reduce a cost of the memory device of a memory system by enabling use of a less complicated power distribution network. The bank-level self-refresh may also be implemented with different types of refresh operations. Amongst other scenarios, bank-level self-refresh can be deployed in memory-expansion environments.

Described apparatuses and methods facilitate bus training with multiple dice, such as multiple memory dice. A controller can communicate with multiple dice over a bus to perform bus training by sending a test pattern and receiving in return a feedback pattern indicative of the bits detected by the dice. Because suitable signal timing can differ between dice, even those using the same bus, the controller may attempt to train each die separately from the others. In some situations, however, individualized training may be infeasible. To accommodate such situations, logic associated with two or more dice can combine the bits as detected from the test pattern into a combined feedback pattern. A timing parameter that is jointly suitable for multiple dice can be determined, and the bus training may be concluded, responsive to the combined feedback pattern matching the test pattern. The multiple dice may be stacked or linked.

Bus training with interconnected dice

Described apparatuses and methods facilitate bus training with multiple dice, such as multiple memory dice. A controller can communicate with multiple dice to perform bus training by sending a test pattern and receiving in return a feedback pattern indicative of the bits detected by the dice. Because suitable signal timing can differ between dice, even those using the same bus, a controller may train each die separately from the others. In some situations, however, individualized training may be infeasible. To accommodate such situations, logic associated with two or more dice can combine, using at least one logical operation, bits as detected from the test pattern into a combined feedback pattern. A timing parameter that is jointly suitable for multiple dice can be determined, and the bus training may be concluded, responsive to the combined feedback pattern matching the test pattern. The multiple dice may be stacked or linked.

Described apparatuses and methods relate to adaptive memory registers for a memory system that may support a nondeterministic protocol. To help manage power-delivery networks in a memory system, a device includes logic that can write values to memory registers associated with memory blocks of a memory array. The values indicate whether an associated memory block has been refreshed within a refresh interval. Other logic can read the registers to determine whether a block has been refreshed. The device also includes logic that can access data indicating a row address that was most recently, or is next to be, refreshed and write values representing the address to another register. The register can be read by other logic to determine whether a wordline potentially affected by an activation-based disturb event is near to being refreshed. These techniques can reduce the number of refresh operations performed, saving power and reducing costs.

Adaptive memory registers

Described apparatuses and methods relate to self-refresh arbitration. In a memory system with multiple memory components, an arbiter is configured to manage the occurrence of self-refresh operations. In aspects, the arbiter can receive one or more self-refresh request signals from at least one memory controller for authorization to command one or more memory components to enter a self-refresh mode. Upon receiving the one or more self-refresh request signals, the arbiter, based on a predetermined configuration, can transmit one or more self-refresh enable signals to the at least one memory controller with authorization to command the one or more memory components to enter the self-refresh mode. The configuration can ensure that fewer than all memory components simultaneously enter the self-refresh mode. In so doing, memory components can perform self-refresh operations without exceeding an instantaneous power threshold. The arbiter can be included in, for instance, a Compute Express Link™ (CXL™) memory module.

Self-refresh arbitration

Memory devices have an array of elements in two or more dimensions. The memory devices use multiple access lines arranged in a grid to access the memory devices. Memory cells are located at intersections of the access lines in the grid. Drivers are used for each access line and configured to transmit a corresponding signal to respective memory cells of the plurality of memory cells via a corresponding access line. The memory devices also include compensation circuitry configured to determine which driving access lines driving a target memory cell of the plurality of memory cells has the most distance between the target memory cell and a respective driver. The plurality of access lines comprise the driving access lines. The compensation circuitry also is configured to output compensation values to adjust the voltages of the driving access lines based on a polarity of the voltage of the longer driving access line.

Electrical distance-based wave shaping for a memory device

Methods, systems, and devices for a refresh operation of a memory cell are described. A memory device may include a plurality of rows of memory cells. Each row of memory cells may undergo a quantity of access operations (e.g., read operations, write operations). During a read operation, a logic state of one or more memory cells may be determined by applying a read pulse having a first polarity. Based on the one or more memory cells storing a particular logic state (e.g., a first logic state), a refresh operation may be performed. During a refresh operation, a refresh pulse having a second polarity (e.g., a different polarity than the first polarity) may be applied to the one or more memory cells.

Refresh operation of a memory cell

Memory devices may have an array of elements in two or more dimensions. The memory devices use multiple access lines arranged in a grid to access the memory devices. Memory cells located at intersections of the access lines in the grid. Drivers are used for each access line and configured to transmit a corresponding signal to respective memory cells of the plurality of memory cells via a corresponding access line. The memory devices uses an electrical distance calculator to determine an electrical distance from a memory cell to a respective driver of the plurality of drivers. The memory device also uses a driver modulator to modulate the corresponding signal based at least in part on the electrical distance.

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Boise, ID, United States of America

John Christopher Sancon