Showing papers on "Memory refresh published in 2007"

Nonvolatile Semiconductor Memory Device

Abstract: A memory cell array has a first and a second storage area. The first storage area has a memory elements selected by an address signal. The second storage area has a memory elements selected by a control signal. A control circuit has a fuse element. When the fuse element has been blown, the control circuit inhibits at least one of writing and erasing from being done on the second storage area.

Smart Refresh: An Enhanced Memory Controller Design for Reducing Energy in Conventional and 3D Die-Stacked DRAMs

Abstract: DRAMs require periodic refresh for preserving data stored in them. The refresh interval for DRAMs depends on the vendor and the de- sign technology they use. For each refresh in a DRAM row, the stored information in each cell is read out and then written back to itself as each DRAM bit read is self-destructive. The refresh pro- cess is inevitable for maintaining data correctness, unfortunately, at the expense of power and bandwidth overhead. The future trend to integrate layers of 3D die-stacked DRAMs on top of a proces- sor further exacerbates the situation as accesses to these DRAMs will be more frequent and hiding refresh cycles in the available slack becomes increasingly difficult. Moreover, due to the implica- tion of temperature increase, the refresh interval of 3D die-stacked DRAMs will become shorter than those of conventional ones. This paper proposes an innovative scheme to alleviate the en- ergy consumed in DRAMs. By employing a time-out counter for each memory row of a DRAM module, all the unnecessary periodic refresh operations can be eliminated. The basic concept behind our scheme is that a DRAM row that was recently read or written to by the processor (or other devices that share the same DRAM) does not need to be refreshed again by the periodic refresh opera- tion, thereby eliminating excessive refreshes and the energy dissi- pated. Based on this concept, we propose a low-cost technique in the memory controller for DRAM power reduction. The simulation results show that our technique can reduce up to 86% of all refresh operations and 59.3% on the average for a 2GB DRAM. This in turn results in a 52.6% energy savings for refresh operations. The overall energy saving in the DRAM is up to 25.7% with an average of 12.13% obtained for SPLASH-2, SPECint2000, and Biobench benchmark programs simulated on a 2GB DRAM. For a 64MB 3D DRAM, the energy saving is up to 21% and 9.37% on an average when the refresh rate is 64 ms. For a faster 32ms refresh rate the maximum and average savings are 12% and 6.8% respectively.

Write Strategies for 2 and 4-bit Multi-Level Phase-Change Memory

Abstract: We discuss novel multi-level write algorithms for phase change memory which produce highly optimized resistance distributions in a minimum number of program cycles. Using a novel integration scheme, a test array at 4 bits/cell and a 32 kb memory page at 2 bits/cell are experimentally demonstrated.

Flash memory with coding and signal processing

Abstract: A solid state non-volatile memory unit includes, in part, an encoder, a multi-level solid state non-volatile memory array adapted to store data encoded by the encoder, and a decoder adapted to decode the data retrieved from the memory array. The memory array may be a flash EEPROM array. The memory unit optionally includes a modulator and a demodulator. The data modulated by the modulator is stored in the memory array. The demodulator demodulates the modulated data retrieved from the memory array.

Method and system for error correction in flash memory

Abstract: A solid state non-volatile memory unit. The memory unit includes a multi-level solid state non-volatile memory array adapted to store data characterized by a first number of digital levels. The memory unit also includes an analog-to-digital converter having an input and an output. The input of the analog-to-digital converter is adapted to receive data from the multi-level solid state non-volatile memory array. The output of the analog-to-digital converter is adapted to output a digital signal characterized by a second number of digital levels greater than the first number of digital levels.

Multi-die memory device

Abstract: An integrated circuit (IC) package includes an interface die and a separate storage die. The interface die has a synchronous interface to receive memory access commands from an external memory controller, and has a plurality of clockless memory control interfaces to output row and column control signals that correspond to the memory access commands. The storage die has a plurality of independently accessible storage arrays and corresponding access-control interfaces to receive the row and column control signals from the clockless memory control interfaces, each of the access-control interfaces including data output circuitry to output read data corresponding to a given one of the memory access commands in a time-multiplexed transmission.

Switch/network adapter port incorporating shared memory resources selectively accessible by a direct execution logic element and one or more dense logic devices in a fully buffered dual in-line memory module format (FB-DIMM)

Abstract: An enhanced switch/network adapter port incorporating shared memory resources (“SNAPM™”) selectively accessible by a direct execution logic element and one or more dense logic devices in a fully buffered dual in-line memory module (“FB-DIMM”) format for clustered computing systems employing direct execution logic such as multi-adaptive processor elements (“MAP®”, all trademarks of SRC Computers, Inc.). Functionally, the SNAPM modules incorporate and properly allocate memory resources so that the memory appears to the associated dense logic device(s) (e.g. a microprocessor) to be functionally like any other system memory such that no time penalties are incurred when accessing it. Through the use of a programmable access coordination mechanism, the control of this memory can be handed off to the SNAPM memory controller and, once in control, the controller can move data between the shared memory resources and the computer network such that the transfer is performed at the maximum rate that the memory devices themselves can sustain. This provides the highest performance link to the other network devices such as MAP® elements, common memory boards and the like.

Reducing programming error in memory devices

Abstract: A method for storing data in an array (28) of analog memory cells (32) includes defining a constellation of voltage levels (90A, 90B, 90C, 90D) to be used in storing the data. A part of the data is written to a first analog memory cell in the array by applying to the analog memory cell a first voltage level selected from the constellation. After writing the part of the data to the first analog memory cell, a second voltage level that does not belong to the constellation is read from the first analog memory cell. A modification to be made in writing to one or more of the analog memory cells in the array is determined responsively to the second voltage level, and data are written to the one or more of the analog memory cells subject to the modification.

Memory circuit system and method

Abstract: A memory circuit system and method are provided. In one embodiment, an interface circuit is capable of communication with a plurality of memory circuits and a system. In use, the interface circuit is operable to interface the memory circuits and the system for reducing command scheduling constraints of the memory circuits. In another embodiment, an interface circuit is capable of communication with a plurality of memory circuits and a system. In use, the interface circuit is operable to translate an address associated with a command communicated between the system and the memory circuits. In yet another embodiment, at least one memory stack comprises a plurality of DRAM integrated circuits. Further, a buffer circuit, coupled to a host system, is utilized for interfacing the memory stack to the host system for transforming one or more physical parameters between the DRAM integrated circuits and the host system. In still yet another embodiment, at least one memory stack comprises a plurality of DRAM integrated circuits. Further, an interface circuit, coupled to a host system, is utilized for interfacing the memory stack to the host system so to operate the memory stack as a single DRAM integrated circuit.

Memory module with memory stack and interface with enhanced capabilities

Abstract: A memory module, which includes at least one memory stack, comprises a plurality of DRAM integrated circuits and an interface circuit. The interface circuit interfaces the memory stack to a host system so as to operate the memory stack as a single DRAM integrated circuit. In other embodiments, a memory module includes at least one memory stack and a buffer integrated circuit. The buffer integrated circuit, coupled to a host system, interfaces the memory stack to the host system so to operate the memory stack as at least two DRAM integrated circuits. In yet other embodiments, the buffer circuit interfaces the memory stack to the host system for transforming one or more physical parameters between the DRAM integrated circuits and the host system.

Method of writing data to a semiconductor memory device

Abstract: A method of writing data to a semiconductor memory device with memory cells, each of which stores data defined by threshold voltage thereof in a non-volatile manner, the device having first and second memory cells disposed adjacent to each other to be sequentially written in this order, the method including: performing a first data write operation for writing data defined by a threshold voltage lower than a desired threshold voltage into the first memory cell; performing a second data write operation for writing data into the second memory cell; and performing a third data writing operation for writing data defined by the desired threshold voltage into the first memory cell.

NAND flash module replacement for DRAM module

Abstract: An electronic memory module according to the invention provides non-volatile memory that can be used in place of a DRAM module without battery backup. An embodiment of the invention includes an embedded microprocessor with microcode that translates the FB-DIMM address and control signals from the system into appropriate address and control signals for NAND flash memory. Wear-leveling, bad block management, garbage collection are preferably implemented by microcode executed by the microprocessor. The microprocessor, additional logic, and embedded memory provides the functions of a flash memory controller. The microprocessor memory preferably contains address mapping tables, free page queue, and garbage collection information.

Flash memory device and system with randomizing for suppressing errors

Abstract: A device for storing data includes a nonvolatile memory and a controller and/or circuitry that randomize original data to be stored in the memory while preserving the size of the original data, that store the original data in the memory, and that, in response to a request for the original data, retrieve, derandomize and export the original data without authenticating the requesting entity. A system for storing data includes a first nonvolatile memory and a processor that similarly stores data in the first nonvolatile memory by executing driver code stored in a second nonvolatile memory. ECC encoding is applied either before or after randomizing; correspondingly, ECC decoding is applied either after or before derandomizing.

Memory Module With Reduced Access Granularity

Abstract: A memory module having reduced access granularity. The memory module includes a substrate having signal lines thereon that form a control path and first and second data paths, and further includes first and second memory devices coupled in common to the control path and coupled respectively to the first and second data paths. The first and second memory devices include control circuitry to receive respective first and second memory access commands via the control path and to effect concurrent data transfer on the first and second data paths in response to the first and second memory access commands.

Multi-bit memory cell having electrically floating body transistor, and method of programming and reading same

Abstract: Multi-bit memory cell and circuitry and techniques for reading, writing and/or operating a multi-bit memory cell (and memory cell array having a plurality of such memory cells) having one or more electrically floating body transistors in which an electrical charge is stored in the body region of the electrically floating body transistor. The multi-bit memory cell stores more than one data bit (for example, two, three, four, five, six, etc ) and/or more than two data states (for example, three, four, five, six, etc. data or logic states. Notably, the memory cell array may comprise a portion of an integrated circuit device, for example, logic device (for example, a microprocessor) or a portion of a memory device (for example, a discrete memory)

Memory device, memory controller and memory system

Abstract: An image memory, image memory system, and memory controller that are capable of efficiently accessing a rectangular area of two-dimensionally arrayed data are provided. The memory device has: a memory cell array that has a plurality of memory unit areas, each of which is selected by addresses; a plurality of input/output terminals; and an input/output unit provided between the memory cell array and the plurality of input/output terminals. Each of the memory unit areas stores therein data of a plurality of bytes or bits corresponding to the plurality of input/output terminals respectively, and the memory cell array and the input/output unit access a plurality of bytes or bits stored in a first memory unit area corresponding to the input address and in a second memory unit area adjacent to the first memory unit on the basis of the input address and combination information of the bytes or bits in response to a first operation code, and then, from the plurality of bytes or bits within the accessed first and second memory unit areas, associate a combination of the plurality of bytes or bits based on the combination information, with the plurality of input/output terminals.

Memory array having a programmable word length, and method of operating same

Abstract: A memory cell array and device having a memory cell array (i.e., an integrated circuit device, for example, a logic device (such as, a microcontroller or microprocessor) or a memory device (such as, a discrete memory)) including electrically floating body transistors in which electrical charge is stored in the body of the transistor, and techniques for reading, controlling and/or operating such memory cell array and such device. The memory cell array and device include a variable and/or programmable word length. The word length relates to the selected memory cells of a selected row of memory cells (which is determined via address data). In one embodiment, the word length may be any number of memory cells of a selected row which is less than or equal to the total number of memory cells of the selected row of the memory array. In one aspect, write and/or read operations may be performed with respect to selected memory cells of a selected row of the memory array, while unselected memory cells of the selected row are undisturbed.

System and method for simulating an aspect of a memory circuit

Abstract: A memory subsystem is provided including an interface circuit adapted for coupling with a plurality of memory circuits and a system. The interface circuit is operable to interface the memory circuits and the system for emulating at least one memory circuit with at least one aspect that is different from at least one aspect of at least one of the plurality of memory circuits. Such aspect includes a signal, a capacity, a timing, and/or a logical interface.

Dynamic cell bit resolution

Abstract: A system and method, including computer software, is used to write to a flash memory device that includes multiple memory cells. One or more of the memory cells are written at a first resolution corresponding to a first number of bits of data. A signal to write at a second resolution corresponding to a second number of bits of data is received. One or more of the memory cells are written at the second resolution.

Memory module decoder

Abstract: A memory module connectable to a computer system includes a printed circuit board, a plurality of memory devices coupled to the printed circuit board, and a logic element coupled to the printed circuit board. The plurality of memory devices has a first number of memory devices. The logic element receives a set of input control signals from the computer system. The set of input control signals corresponds to a second number of memory devices smaller than the first number of memory devices. The logic element generates a set of output control signals in response to the set of input control signals. The set of output control signals corresponds to the first number of memory devices.

High-speed controller for phase-change memory peripheral device

Abstract: Peripheral devices store data in non-volatile phase-change memory (PCM). PCM cells have alloy resistors with high-resistance amorphous states and low-resistance crystalline states. The peripheral device can be a Multi-Media Card/Secure Digital (MMC/SD) card. A PCM controller accesses PCM memory devices. Various routines that execute on a CPU in the PCM controller are activated in response to commands in the host-bus transactions. The PCM system increases the throughput of one or more phase-change memory devices by performing one or more of a read-ahead memory operation, a write-ahead memory write operation, a larger page memory write operation, a wider data bus memory write operation, a multi-channel concurrent multi-bank interleaving memory read or write operation, a write-cache memory write operation, and any combination thereof.

Method and Apparatus For Refresh Management of Memory Modules

Abstract: One embodiment sets forth an interface circuit configured to manage refresh command sequences that includes a system interface adapted to receive a refresh command from a memory controller, clock frequency detection circuitry configured to determine the timing for issuing staggered refresh commands to two or more memory devices coupled to the interface circuit based on the refresh command received from the memory controller, and at least two refresh command sequence outputs configured to generate the staggered refresh commands for the two or more memory devices

System and memory for sequential multi-plane page memory operations

Abstract: A system and method for performing memory operations in a multi-plane flash memory Commands and addresses are sequentially provided to the memory for memory operations in memory planes The memory operations are sequentially initiated and the memory operation for at least one of the memory planes is initiated during the memory operation for another memory plane In one embodiment, each of a plurality of programming circuits is associated with a respective memory plane and is operable to program data to the respective memory plane in response to programming signals and when it is enabled Control logic coupled to the plurality of programming circuits generates programming signals in response to the memory receiving program commands and further generates programming enable signals to individually enable each of the programming circuits to respond to the programming signals and stagger programming of data to each of the memory planes

Memory system including flash memory and method of operating the same

Abstract: A method for operating a memory system including a flash memory device having a plurality of memory blocks includes determining whether a read error generated during a read operation of the flash memory device is caused by read disturbance and replacing a memory block which includes the read error, with a spare memory block if the read error is caused by read disturbance.

System and method for reducing command scheduling constraints of memory circuits

Abstract: A memory circuit system and method are provided. An interface circuit is capable of communication with a plurality of memory circuits and a system. In use, the interface circuit is operable to interface the memory circuits and the system for reducing command scheduling constraints of the memory circuits.

Advancing and rewinding a replayed program execution

Abstract: In an embodiment, a data processing system comprises a storage system coupled to a unit under test comprising a heap memory, a static memory and a stack; second logic operable to perform: detecting one or more changes in a first state of the heap memory and the static memory; storing, in the storage system, as a state point of the unit under test, the one or more changes in the first state of the heap memory and the static memory; third logic operable to perform: receiving a request to change the memory under test to a particular state point; in response to the request, loading the particular state point from the storage system and applying the state point to the heap memory and the static memory to result in changing the heap memory and the static memory to a second state that is substantially equivalent to the first state.

Flash memory controller controlling various flash memory cells

Abstract: An electronic data flash card is accessible by a host system, and includes a flash memory controller and at least one flash memory device coupled to the flash controller. The boot code and control code for the flash memory system (flash card) are stored in the flash memory device during a programming procedure. The flash controller transfers the boot code and control code to a volatile main memory (e.g., random access memory or RAM) at start up or reset making a RAM-based memory system. Boot code and control code are selectively overwritten during a code updating operation. A single flash controller thus supports multiple brands and types of flash memory to eliminate stocking issues.

Apparatus and method for reduced peak power consumption during common operation of multi-nand flash memory devices

Abstract: System and method for executing a global memory command in a multi-chip non-volatile memory device having a plurality of non-volatile memories. The global memory command is received at each non-volatile memory concurrently. The memory command is initiated at different times relative to receiving the global memory command for at least two of the plurality of non-volatile memory to mitigate peak power consumption.

Methods and apparatus of dual inline memory modules for flash memory

Abstract: In one implementation, flash memory chips are provided with an operating power supply voltage to substantially match a power supply voltage expected at an edge connector of a dual inline memory module. The one or more of the flash memory chips and a memory support application integrated circuit (ASIC) may be mounted together into a multi-chip package for integrated circuits. The one or more flash memory chips and the memory support ASIC may be electrically coupled together by routing one or more conductors between each in the multi-chip package. The multi-chip package may be mounted onto a printed circuit board (PCB) of a flash memory DIMM to reduce the number of packages mounted thereto and reduce the height of the flash memory DIMM. The number of printed circuit board layers may also be reduced, such as by integrating address functions into the memory support ASIC.

Relocating data in a memory device

Abstract: Systems and methods that can facilitate more optimized relocation of data associated with a memory are presented. In addition to a memory controller component, a memory manager component can be employed to increase available processing resources to facilitate more optimal execution of higher level functions. Higher level functions can be delegated to the memory manager component to allow execution of these higher level operations with reduced or no load on the memory controller component resources. A uni-bus or multi-bus architecture can be employed to further optimize data relocation operations. A first bus can be utilized for data access operations including read, write, erase, refresh, or combinations thereof, among others, while a second bus can be designated for higher level operations including data compaction, error code correction, wear leveling, or combinations thereof, among others.