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Hiroshi Maejima

Hiroshi Maejima, Tokyo JP

Patent application numberDescriptionPublished
20100097127BOOSTER CIRCUIT AND VOLTAGE SUPPLY CIRCUIT - A voltage supply circuit includes a booster circuit and a ripple filter circuit. The ripple filter circuit has a first resistor connected to a first output terminal at one end thereof. The ripple filter circuit also has a first switch circuit connected between the other end of the first resistor and a second output terminal. In addition, the ripple filter circuit has a second switch circuit connected between the first output terminal of the booster circuit and the first switch circuit.04-22-2010
20100097860NAND FLASH MEMORY - A NAND flash memory, in a read operation, a p-type semiconductor substrate is set at a ground potential, a bit line is charged to a first voltage, a source line, a n-type well and a p-type well are charged to a second voltage, which lies between a ground potential and a first voltage, and in a block not selected by said row decoder, said drain-side select gate line and said source-side select gate line are charged to a third voltage, which is higher than said ground potential and is equal to or lower than said second voltage.04-22-2010
20100208510SEMICONDUCTOR MEMORY DEVICE AND METHOD OF OPERATING THE SAME - A semiconductor memory device comprises: a memory cell array having memory cells disposed at a crossing-point of a plurality of first lines and a plurality of second lines; and a control circuit configured to apply a first voltage to selected one of the first lines, and to apply a second voltage to selected one of the second lines. The control circuit comprises: a first isolation latch circuit configured to set the first lines to a floating state; and a second isolation latch circuit configured to set the second lines to the floating state. During a forming operation, the first and second isolation latch circuits set one of the first lines and one of the second lines to which a defective memory cell is connected to the floating state, the defective memory cell being one of the memory cells that allows a current to flow due to application of a voltage.08-19-2010
20100214820SEMICONDUCTOR MEMORY DEVICE - A semiconductor memory device comprises: a memory cell array having memory cells disposed at a crossing-point of a plurality of first lines and a plurality of second lines and a control circuit configured to apply a first voltage to selected one or more of the first lines, and to apply a second voltage having a value smaller than the first voltage to selected one of the second lines, such that a certain potential difference is applied to selected one or more of the memory cells. The control circuit adjusts the second voltage based on a position of the selected one or more of the memory cells within the memory cell array and a number of the selected one or more of the memory cells on which an operation is simultaneously executed, during application of the potential difference to the selected one or more of the memory cells.08-26-2010
20110069533RESISTANCE CHANGE MEMORY AND CONTROL METHOD THEREOF - According to one embodiment, a resistance change memory includes a memory cell array in which a plurality of blocks are provided, resistance change storage elements which are provided in blocks and which store data in accordance with a change in resistance state, first and second wirings in the blocks, each of the first and second wirings being connected to each of resistance change storage elements, and a control circuit which controls the state of a selected block targeted for operation and the state of unselected blocks except the selected block among the blocks. The control circuit respectively applies first and second unselect potentials to the first and second wirings in at least one of the unselected blocks during a period in which the selected block is in operation.03-24-2011
20110116300NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - A nonvolatile semiconductor memory device according to an embodiment comprises a memory cell array including plural mutually crossing first and second lines and memory cells arranged at intersections of the first and second lines, each memory cell containing a variable resistance element and a rectifier element connected in series; and a data write/erase circuit operative to apply a voltage required for data write/erase to the memory cell via the first and second lines. The data write/erase circuit includes a first current limit circuit operative to limit the current flowing in the cathode-side line provided on the cathode side of the rectifier element, of the first and second lines, at the time of data write/erase.05-19-2011
20110140766BOOSTER CIRCUIT AND VOLTAGE SUPPLY CIRCUIT - A booster circuit includes a pump circuit having a plurality of charge pump circuits for outputting a boosted voltage to a first output terminal. The booster circuit also includes a clock adjusting circuit that generates, from a first clock signal, a second clock signal for operating the charge pump circuits. A pump controlling circuit outputs the first clock signal for operating the pump circuit. A first comparator outputs a first output signal. A second comparator outputs a second output signal. A third comparator outputs a third output signal. A gradient of the boosted voltage is decreased when the first output signal is output. A frequency of the first clock signal is reduced when the second output signal is output. The third output signal is output when the boosted voltage is higher than a set value of the boosted voltage.06-16-2011
20110149653NAND FLASH MEMORY - A NAND flash memory, in a read operation, a p-type semiconductor substrate is set at a ground potential, a bit line is charged to a first voltage, a source line, a n-type well and a p-type well are charged to a second voltage, which lies between a ground potential and a first voltage, and in a block not selected by said row decoder, said drain-side select gate line and said source-side select gate line are charged to a third voltage, which is higher than said ground potential and is equal to or lower than said second voltage.06-23-2011

Patent applications by Hiroshi Maejima, Tokyo JP

Hiroshi Maejima, Kanagawa-Ken JP

Patent application numberDescriptionPublished
20100027317SEMICONDUCTOR MEMORY DEVICE - A semiconductor memory device comprising: a memory cell array in which memory cells each containing a variable resistive element and a rectifier element connected in series are arranged at intersections of a plurality of first wirings and a plurality of second wirings; and a control circuit for selectively driving said first wirings and said second wirings; wherein said control circuit applies a first voltage to said selected first wiring, and changes said first voltage based on the position of said selected memory cell within said memory cell array to apply a second voltage to said selected second wiring, so that a predetermined potential difference is applied to a selected memory cell arranged at the intersection between said selected first wiring and said selected second wiring.02-04-2010
20100054017SEMICONDUCTOR MEMORY DEVICE - A semiconductor memory device comprising: a plurality of cell arrays having a plurality of first wirings and a plurality of second wirings intersecting each other and memory cells disposed at intersections between said first wirings and said second wirings, each containing a variable resistive element that is electrically rewritable and stores a resistance value as data; and a control circuit for selectively driving said first wirings and said second wirings; wherein said control circuit performs a first operation of applying a voltage required for one operation selected from the data write, read and erase operations to said one memory cell via one combination of said first and second wirings and a second operation of applying a voltage required for an operation selected from the data write, read and erase operations and different from the first operation to said other memory cell via another combination of said first and second wirings.03-04-2010
20100097832NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - A nonvolatile-semiconductor-memory-device including a cell array having a plurality of MATs (unit-cell-array) disposed in a matrix, the MATs each include a plurality of first lines, a plurality of second lines crossing the first lines, and memory cells being connected between the first and second lines. The device further includes a first and second drive circuit selecting the first and second lines connected to the memory cells of each MAT that are accessed, and driving the selected first and second lines to write or read data. The memory cells form a page by being connected to each first line selected from the MATs. The device also includes a data latch latching the write or the read data in units of pages, where the first and second drive circuit drive the first and second lines multiple times to write or read data for one page in and out of the cell array.04-22-2010

Hiroshi Maejima, Suginami-Ku JP

Patent application numberDescriptionPublished
20100013549VOLTAGE GENERATION CIRCUIT AND SEMICONDUCTOR MEMORY USING THE SAME - The voltage generation circuit that have a standard voltage generation circuit that generates a reference voltage; a minimum voltage setting circuit that sets a minimum voltage; a voltage setting circuit that has a plurality of resistive elements and a plurality of gate transistors connected to a plurality of the resistive elements, and gradually sets voltage by switching a plurality of the gate transistors to switch a combination of a plurality of the resistive elements; a differential amplifier that has two input terminals and one output node, one input terminal is connected to the reference voltage that is generated by the standard voltage generation circuit, another input terminal is connected to the minimum voltage setting circuit and the voltage setting circuit that has a plurality of resistive elements and a plurality of gate transistors connected to a plurality of the resistive elements, and the output node shows the result of the difference voltage of these two inputs; a pump control circuit that outputs a control signal controlling a charge-pump motion, based on the differential voltage; and a charge pump circuit that sets up and outputs the voltage by the control signal.01-21-2010
20110163798VOLTAGE GENERATION CIRCUIT AND SEMICONDUCTOR MEMORY USING THE SAME - The voltage generation circuit having a standard voltage generation circuit, a reference voltage, a minimum voltage setting circuit, and a voltage setting circuit that gradually sets voltage by switching a plurality of the gate transistors to switch a combination of resistive elements. The voltage generation circuit includes a differential amplifier that has one input terminal connected to the reference voltage generated by the standard voltage generation circuit and another input terminal connected to the minimum voltage setting circuit. The differential amplifier has an output node showing the result of a difference voltage of the inputs. The voltage generation circuit includes a pump control circuit that outputs a control signal controlling a charge-pump motion, based on the differential voltage, and a charge pump circuit that sets up and outputs the voltage by the control signal.07-07-2011

Patent applications by Hiroshi Maejima, Suginami-Ku JP