Abstract: Methods of providing a delay for access to a memory device can include adjusting a delay for access to data during memory operations based on at least one parameter associated with a reduction in voltage levels provided to the memory. Related circuits are also disclosed.
Abstract: A nonvolatile memory device, including a plurality of memory cell blocks, N memory cell blocks (N is an integer equal to or greater than 2) being arranged in a row direction, L memory cell blocks (L is an integer equal to or greater than 2) being arranged in a column direction, and each of the memory cell blocks including M memory cells (M is an integer equal to or greater than 2), a plurality of wordlines, a plurality of first control gate lines, a plurality of first control gate switches, a plurality of second control gate lines, and a plurality of bitlines.
Abstract: A self-refresh module includes an oscillator configured to provide a first signal having a first frequency, a trimming divider configured to trim the first signal to provide a second signal having a second frequency, and a temperature sensor configured to sense a temperature of the memory device and provide a temperature signal. The self-refresh module includes a temperature look-up table configured to receive the temperature signal and provide a third signal based on the temperature signal, and a temperature divider configured to provide a self-refresh pulse signal based on the second signal and the third signal.
Abstract: One embodiment of the present invention provides a system that reduces the number of power and ground pins required to drive address signals to system memory. During operation, the system receives address signals associated with a memory operation from a memory controller, wherein the address signals are received at a buffer chip, which is external the memory controller. The system also receives chip select signals associated with the memory operation at the buffer chip. Next, the system uses the chip select signals to identify an active subset of memory modules in the system memory, which are active during the memory operation. The system then uses address drivers on the buffer chip to drive the address signals only to the active subset of memory modules, and not to other memory modules in the system memory.
Abstract: A method for repairing cells of a flash memory array includes using a fuse memory array circuit. The fuse memory cells are initially programmed. The locations of defective memory cells of the main array are determined. These locations are stored in the fuse memory cells by erasing predetermined locations in the fuse memory cell array so that the locations are programmed.
Abstract: An erasable and programmable non-volatile cell, comprising a first transistor having a source, a drain and a gate; a floating capacitor having a floating gate and a control gate, said floating gate being connected to said gate of said first transistor; and means to detect the state, whether erased or programmed, of the cell; is characterized in that said means to detect the state of the cell comprises a second transistor having a source, a drain and a gate, said second transistor being complementary to said first transistor and said gate of said second transistor being connected to said floating gate.
Abstract: A semiconductor memory device includes a word drive line, and a word line connected with memory cells. A first drive circuit drives the word drive line to a first voltage based on a main word signal, and resets the word drive line to a ground voltage in a time period for transition of an address signal. A second drive circuit outputs a signal of the first voltage to the word line based on a sub-word signal such that a data is read out from one of the memory cells. The main word signal and the sub-word signal are obtained from an address signal, and are signals taking the ground voltage or a second voltage which is lower than the first voltage.
Abstract: The present invention relates to an electronic device comprising a memory cell with a resistive storage element having a first terminal and a second terminal. The resistive storage element can be switched between a first storage state with a first conductivity and a second storage state with a second conductivity. An access switch is coupled to the first terminal of the resistive storage element and to a node for connecting the first terminal of the resistive storage element to the node in an access state of the memory cell and for insulating the first terminal of the resistive storage element from the node in an idle state of the memory cell. A protecting switch is connected to the resistive storage element. The protecting switch, in the idle state of the memory cell, reduces the voltage across the resistive storage element produced by electromagnetic interference and, in the access state of the memory cell, enables the reading and the writing of the storage states of the resistive storage element.
Abstract: Write control circuitry and control method are provided for a memory array configured with multiple memory subarrays. The write control circuitry includes multiple subarray write controllers associated with the multiple memory subarrays, each subarray write controller selectively enabling a local write control signal to its associated memory subarray. The selectively enabling is responsive to a received subarray select signal, wherein only one subarray select signal is active at a time. At least some subarray write controllers are powered at least in part via a switched power node, wherein powering of the switched power node is distributively implemented among the subarray write controllers. In one example, the distributively implemented powering of the switched power node is accomplished via multiple inverters distributed among the subarray write controllers, each inverter having an output coupled to the switched power node, and an input coupled to receive a global write enable signal.
Type:
Grant
Filed:
February 9, 2005
Date of Patent:
October 16, 2007
Assignee:
International Business Machines Corporation
Inventors:
John D. Davis, Paul A. Bunce, Donald W. Plass, Kenneth J. Reyer
Abstract: A semiconductor memory device able to read out data at a high speed continuously, provided with, corresponding to a plurality of banks, current address registers for holding addresses for reading data of cell arrays, reserved address registers able to receive in advance and hold reserved addresses for next read operations from the outside, and bank control circuits for making the current address registers hold reserved addresses held in the reserved address registers, making the data be read out, and making the data latch circuits hold the data when the data read out from the cell arrays of the banks by addresses held in the current address registers and held in the data latch circuits become able to be transferred to the outside, and a signal processing system relating to the same.
Abstract: A method and system is disclosed for a wordline driver circuit used for a memory device. It has a logic stage operating between a ground voltage and a first supply voltage and generating a logic stage output signal swinging between the ground voltage and the first supply voltage. It also has a mid voltage stage, operating between a raised ground voltage and a second supply voltage during the programming process, and generating a mid voltage stage output that swings between the second supply voltage and the raised ground voltage. It then has a high voltage stage, operating between the raised ground voltage and a third supply voltage, and generating a wordline driver output swinging between the third supply voltage and the raised ground voltage based on the received mid voltage stage output.
Abstract: Each memory cell of an MRAM that uses toggle writing is written by applying to the memory cell a first field, then a combination of the first field and the second field, then the second field. The removal of the second field ultimately completes the writing of the memory cell. The combination of the first field and the second field is known to saturate a portion, the synthetic antiferromagnet (SAF), of the MRAM cell being written. This can result in not knowing which logic state is ultimately written. This is known to be worsened at higher temperatures. To avoid this deleterious saturation, the magnetic field is reduced during the time when both fields are applied. This is achieved by reducing the current that provides these fields from the current that is applied when only one of the fields is applied.
Abstract: The present invention provides a magnetoresistive memory cell (30), comprising a magnetoresistive memory element (31), a first current line (32) and a second current line (33), the first and the second current line (32, 33) crossing each other at a cross-point region but not being in direct contact. According to the invention, a bridging element(34) connects the first and second current lines (32, 33) in the vicinity of the cross-point region. The bridging element (34) is magnetically couplable to the magnetoresistive memory element (31). An advantage of the MRAM architecture according to the present invention is that it allows lower power consumption than prior art devices and high selectivity during writing. The present invention also provides a method of writing a value in a matrix of magnetoresistive memory cells (30) according to the present invention, and a method of manufacturing such magnetoresistive memory cells (30).
Abstract: A method is provided comprising reading a set of memory cells indicating whether stored redundancy information is reliable and, if the set of memory cells indicates that the stored redundancy information is reliable, determining whether to read primary memory or redundant memory based on the stored redundancy information. Another method is provided comprising reading a set of memory cells associated with a group of memory cells in a primary memory, the set of memory cells indicating whether data can be reliably stored in the group of memory cells; if the set of memory cells indicates that data can be reliably stored in the group of memory cells, storing data in the group of memory cells; and if the set of memory cells does not indicate that data can be reliably stored in the group of memory cells, storing data in a group of memory cells in a redundant memory. In another preferred embodiment, a method for providing memory redundancy is provided.
Abstract: A method for programming a phase-change memory array and circuit of a phase-change memory device, each having a plurality of phase-change memory cells, may enable all the phase-change memory cells therein to be changed or set at a set resistance state, and may reduce the time needed to change the phase-change memory array to the set resistance state. In the method, a set current pulse having first through nth stages may be applied to the cells of the array to change the cells to the set resistance state. A minimum current level of the set current pulse applied to the phase-change memory cells in any stage may be higher than a reference current level for the cells of the array. A given current level of the set current pulse may be sequentially reduced from stage to stage.
Type:
Grant
Filed:
March 3, 2005
Date of Patent:
September 25, 2007
Assignee:
Samsung Electronics Co., Ltd.
Inventors:
Byung-Gil Choi, Du-Eung Kim, Choong-Keun Kwak, Beak-Hyung Cho
Abstract: An apparatus and method for coupling a normal bit line pair and a second bit line pair onto a desired bit line pair are described. This method comprises driving the desired bit line pair to emulate the normal bit line pair during a read cycle. Additionally, if the second bit line pair is active, the apparatus and method include overdriving the desired bit line pair with strength sufficient to overpower the normal bit line pair, such that the desired bit line pair emulates the second bit line pair. Electrical current differences in the bit line pair may be sensed by a sense amplifier to assert or negate a data output such that it emulates the desired bit line pair. The normal bit line pair may be coupled to a normal memory column and the second bit line pair may be coupled to a redundant memory column.
Abstract: A flash cell fuse circuit includes a fuse cell array, a plurality of switch circuits and a plurality of fuse sense amplifiers. The fuse cell array outputs first signals in response to word line enable signals after a program or erase operation. The switch circuits pass one of the first signals in response to a reset signal and one of the word line enable signals. The fuse sense amplifiers each generate a fuse signal by detecting and amplifying an output signal of a corresponding switch circuit.
Abstract: A method and circuitry for alleviating the adverse effect of variable read decode propagation delays and variable output circuitry propagation delays on the read latency, and specifically for generating output enable signals at an appropriate time in light of such variable delays, is disclosed. In one embodiment, a first time domain as specified by an internal clock is delayed by the propagation delay of the read decoder block plus the propagation delay of the output circuitry via a model to create a second time domain which lags the first time domain. Processing in the second time domain associates the internal read command with a particular external clock cycle, and accounts for the specified read latency of the device. The output of such second time domain processing is a signal indicative of which external cycle should be used to enable the outputs. This signal is then converted back into the first timing domain by latches which lead the second timing domain.
Abstract: A method, system, and circuit for performing a memory related operation are disclosed. An operating voltage is applied to a bitline and a neighboring bitline is precharged. The precharge voltage has a magnitude less than the operating voltage. Both voltages ramp up at like or different rates. The precharge voltage can reach its effective magnitude prior to or with the operating voltage reaching its effective value.