Patents by Inventor Kazuhiko Kajigaya
Kazuhiko Kajigaya has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7345929Abstract: A semiconductor memory device formed on a semiconductor chip includes first memory arrays, a plurality of second memory arrays, a first voltage generator, and first bonding pads. The semiconductor chip is divided into first, second and third rectangle regions and the third rectangle region is arranged between the first rectangle region and the second rectangle region. The first memory arrays are formed in the first rectangle region. The second memory arrays are formed in the second rectangle region. The voltage generator and first bonding pads are arranged in the third rectangle region. The first bonding pads are arranged between the first rectangle region and the voltage generator and no bonding pads are arranged between the voltage generator and the second memory arrays.Type: GrantFiled: March 7, 2007Date of Patent: March 18, 2008Assignees: Hitachi, Ltd., Hitachi ULSI Systems Co., Ltd.Inventors: Kazuhiko Kajigaya, Kazuyuki Miyazawa, Manabu Tsunozaki, Kazuyoshi Oshima, Takashi Yamazaki, Yuji Sakai, Jiro Sawada, Yasunori Yamaguchi, Tetsurou Matsumoto, Shinji Udo, Hiroshi Yoshioka, Hirokazu Saito, Mitsuhiro Takano, Makoto Morino, Sinichi Miyatake, Eiji Miyamoto, Yasuhiro Kasama, Akira Endo, Ryoichi Hori, Jun Etoh, Masashi Horiguchi, Shinichi Ikenaga, Atsushi Kumata
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Publication number: 20080055958Abstract: A semiconductor memory device that can achieve high-speed operation or that is highly integrated and simultaneously can achieve high-speed operation is provided. Transistors are disposed on both sides of diffusion layer regions to which capacitor for storing information is connected and other diffusion layer region of each transistor is connected to the same bit line. When access to a memory cell is made, two transistors are activated and the information is read. When writing operation to the memory cell is carried out, two transistors are used and electric charges are written to the capacitor.Type: ApplicationFiled: October 25, 2007Publication date: March 6, 2008Inventors: Riichiro TAKEMURA, Satoru AKIYAMA, Satoru HANZAWA, Tomonori SEKIGUCHI, Kazuhiko KAJIGAYA
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Publication number: 20080049536Abstract: A semiconductor memory device comprises a plurality of input/output (I/O) ports, a plurality of memory cell arrays and a region configurator. The region configurator is adapted to hold share region information about at least one share region. In the memory cell arrays, at least one share region accessible through the I/O ports is configured on the basis of the share region information.Type: ApplicationFiled: August 21, 2007Publication date: February 28, 2008Applicant: ELPIDA MEMORY INC.Inventor: Kazuhiko Kajigaya
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Publication number: 20080049532Abstract: A semiconductor memory device has a refresh control circuit for switchingly controlling a first refresh mode in which access to the memory cell array from outside is prohibited while retaining data and a second refresh mode in which access to the memory cell array from outside is permitted while retaining data and for performing the refresh operation of the memory cells corresponding to a selected word line, and a designating circuit for individually designating a portion to be refreshed in the first refresh mode and a portion to be refreshed in the second refresh mode. In the semiconductor memory device, the refresh control circuit performs the refresh operation when the portion to which the selected word line belongs is designated to be refreshed, and does not perform the refresh operation when the portion to which the selected word line belongs is not designated to be refreshed.Type: ApplicationFiled: August 21, 2007Publication date: February 28, 2008Applicant: ELPIDA MEMORY, INC.Inventor: Kazuhiko KAJIGAYA
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Patent number: 7333363Abstract: Disclosed is a semiconductor storage apparatus in which two sorts of memories, that is, a volatile memory and a non-volatile memory, are mounted on one chip. Data of a DRAM memory array are saved in a corresponding area of a non-volatile memory before entry to a data retention mode or before power down and data is transferred from the area of the non-volatile memory to the DRAM memory array in exiting from the data retention mode or power up. Normal read/write access is made to the DRAM memory array, while data retention is in an area of the non-volatile memory.Type: GrantFiled: April 24, 2006Date of Patent: February 19, 2008Assignee: Elpida Memory, Inc.Inventors: Kiyoshi Nakai, Kazuhiko Kajigaya, Isamu Asano
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Publication number: 20080037356Abstract: A semiconductor memory device of the invention comprises unit blocks into which the memory cell array is divided, rows of sense amplifiers arranged at one end and the other end of the plurality of bit lines in the unit block, switch means for switching a connection state between the unit block and the row of sense amplifiers attached to the unit block; and control means for controlling the switch means so as to form a transfer path from the row of sense amplifiers attached to a predetermined the unit block leading to the row of sense amplifiers as a saving destination not attached to the predetermined the unit block. This row of sense amplifiers attached to the predetermined the unit block functions as a cache memory.Type: ApplicationFiled: August 6, 2007Publication date: February 14, 2008Applicant: ELPIDA MEMORY, INC.Inventor: Kazuhiko Kajigaya
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Patent number: 7317649Abstract: A semiconductor storage device comprising: unit blocks each including memory cells, first row of sense amplifiers on one side of bit lines; second row of sense amplifiers on an other side of the bit lines; first switch means which switches a connection state between the one side of the bit lines and the first row of sense amplifiers; second switch means which switches a connection state between the other side of the bit lines and the second row of sense amplifiers; third switch means arranged in the approximate center of the bit lines in an extending direction thereof to switch a connection state of the bit lines; and refresh control means which divides the unit block into two areas and controls the refresh operation using the switch means and the row of sense amplifiers according to which area a selected word line to be refreshed is in.Type: GrantFiled: March 31, 2006Date of Patent: January 8, 2008Assignee: Elpida Memory, Inc.Inventor: Kazuhiko Kajigaya
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Publication number: 20080002448Abstract: In a large scale integrated DRAM in pursuit of micro fabrication, data line-word line coupling capacitances are unbalanced between paired data lines. An imbalance in data line-word line means generation of large noise when the data lines are subjected to amplification, which is highly likely invite deterioration of very small signals on the data lines and erroneous amplification of data. One or a few each of a plurality of word lines connected to a plurality of memory cells connected to one data line are alternately connected to subword driver arrays arranged on the opposing sides of a memory array. Positive and negative word line noise components cancel each other in the subword drivers when the data lines are subjected to amplification, so that the word line noise can be reduced. Therefore, signals read out by sense amplifiers can be prevented from deterioration thereby to increase the reliability of memory operation.Type: ApplicationFiled: September 6, 2007Publication date: January 3, 2008Inventors: Tomonori Sekiguchi, Riichiro Takemura, Kazuhiko Kajigaya, Katsutaka Kimura, Tsugio Takahashi
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Publication number: 20080002488Abstract: In a bit-line direction, a plurality of memory mats are arranged including a plurality of memory cells respectively coupled to bit lines and word lines, and a sense amplifier array is arranged including a plurality of latch circuits having input/output nodes connected to a half of bit-line pairs separately provided to the memory mats in a region between the memory mats placed in the bit-line direction, thereby making possible to replace with a redundant bit line pair and the corresponding redundant sense amplifier on a basis of each bit-line pair and sense amplifier connected thereto, thereby realizing effective and rational Y-system relief.Type: ApplicationFiled: August 24, 2007Publication date: January 3, 2008Inventors: Masatoshi HASEGAWA, Kazuhiko Kajigaya
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Publication number: 20070297257Abstract: A dynamic RAM incorporates a plurality of dynamic memory cells, each of which comprises a MOSFET having a gate set as a select terminal, one source and drain set as input/output terminals, and the other source and drain connected to storage nodes of the capacitor and a capacitor, a plurality of word lines respectively connected to the select terminals of the plurality of dynamic memory cells, a plurality of complementary bit line pairs respectively connected to the input/output terminals of the plurality of dynamic memory cells, and a sense amplifier array comprising a plurality of latch circuits which respectively amplify differences in voltage between the complementary bit line pairs placed so as to extend in directions opposite to each other from each pair of input/output terminals. Power supply lines are provided in mesh form inclusive of a portion above word drivers.Type: ApplicationFiled: August 17, 2007Publication date: December 27, 2007Inventors: Tomonori Sekiguchi, Kazuhiko Kajigaya, Katsutaka Kimura, Riichiro Takemura, Tsugio Takahashi, Yoshitaka Nakamura
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Patent number: 7310256Abstract: A semiconductor memory device that can achieve high-speed operation or that is highly integrated and simultaneously can achieve high-speed operation is provided. Transistors are disposed on both sides of diffusion layer regions to which capacitor for storing information is connected and other diffusion layer region of each transistor is connected to the same bit line. When access to a memory cell is made, two transistors are activated and the information is read. When writing operation to the memory cell is carried out, two transistors are used and electric charges are written to the capacitor.Type: GrantFiled: May 23, 2005Date of Patent: December 18, 2007Assignees: Hitachi, Ltd., Elpida Memory, Inc.Inventors: Riichiro Takemura, Satoru Akiyama, Satoru Hanzawa, Tomonori Sekiguchi, Kazuhiko Kajigaya
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Patent number: 7307906Abstract: A semiconductor storage device for storing data to unit blocks of a memory cell array, comprising: two rows of sense amplifiers arranged on both sides of bit lines and each including sense amplifiers; a switch means for switching a connecting state between one row of sense amplifiers and one side of bit lines and switching a connecting state between the other row of sense amplifiers and the other side of bit lines; a control means which sets at least one row of sense amplifiers as a cache memory, and when performing refresh operation of the unit block where row of sense amplifiers to be used as cache memory holds data, controls switch means so that the row of sense amplifiers used as cache memory is disconnected from bit lines and only the row of sense amplifiers not used as said cache memory is used in refresh operation.Type: GrantFiled: March 16, 2006Date of Patent: December 11, 2007Assignee: Elpida Memory Inc.Inventor: Kazuhiko Kajigaya
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Patent number: 7307909Abstract: A self-refresh timer circuit for generating a timer period for controlling self-refresh operation of a semiconductor memory device comprising: a temperature-dependent voltage source for outputting a voltage having a temperature dependency based on a diode characteristic; a control current generating circuit for applying an output voltage of the temperature-dependent voltage source to a temperature detecting device having a diode characteristic and for generating a control current having a magnitude in proportion to a current flowing through the temperature detecting device; and a timer period generating circuit for generating a timer period in inverse proportion to the magnitude of the control current.Type: GrantFiled: December 9, 2005Date of Patent: December 11, 2007Assignee: Elpida Memory Inc.Inventors: Yoshinori Matsui, Hitoshi Tanaka, Kazuhiko Kajigaya, Akiyoshi Yamamoto, Tadashi Onodera
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Patent number: 7304910Abstract: A column circuit that amplifies signals read from a sense amplifier array SAA to local input/output lines LIO in sub-amplifiers SAMP to transfer the amplified signals to main input/output lines MIO is provided. A current control circuit IC that can set one of two kinds of currents according to read enable signals RD1, RD2 is provided in each sub-amplifier SAMP. The read enable signals RD1, RD2 are generated at timings corresponding to the number of cycles in burst read operation under control of the timing controller. Current in the current control circuit IC is set to be large by the RD1 in burst read operation cycle just after activation of a memory bank, while current in the current control circuit IC is set to be small by the RD2 in the next and subsequent burst read cycles. Accordingly, expansion of an operation margin or reduction of power consumption can be realized in a semiconductor device including a semiconductor memory such as a DRAM.Type: GrantFiled: August 28, 2006Date of Patent: December 4, 2007Assignees: Hitachi, Ltd., Elpida Memory, Inc.Inventors: Satoru Hanzawa, Tomonori Sekiguchi, Riichiro Takemura, Satoru Akiyama, Kazuhiko Kajigaya
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Publication number: 20070274136Abstract: There is achieved a high-integrated and high-speed nonvolatile memory which can stabilize an operation of a phase-change memory for a short operation cycle time. A latch is provided in a write driver. A change to a high-resistance state of a phase-change element is performed per column cycle by a write-enable signal, and a change to a low-resistance state thereof is performed after a pre-charge command is inputted and concurrently with deactivation of a pre-charge signal. Thereby, a write time to a memory cell in which phase-change resistance is changed to a low-resistance state, and a period from a write operation for changing the phase-change resistance to a high-resistance state to a read operation to the above memory cell can be lengthened without extending the column cycle time, so that the stable write operation is achieved.Type: ApplicationFiled: August 2, 2007Publication date: November 29, 2007Inventors: Riichiro TAKEMURA, Takeshi SAKATA, Norikatsu TAKAURA, Kazuhiko KAJIGAYA
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Publication number: 20070274144Abstract: In a memory array structured of memory cells using a storage circuit STC and a comparator CP, either one electrode of a source electrode or a drain electrode of a transistor, whose gate electrode is connected to a search line, of a plurality of transistors structuring the comparator CP is connected to a match line HMLr precharged to a high voltage. Further, a match detector MDr is arranged on a match line LMLr precharged to a low voltage to discriminate a comparison signal voltage generated at the match line according to the comparison result of data. According to such memory array structure and operation, comparison operation can be performed at low power and at high speed while influence of search-line noise is avoided in a match line pair. Therefore, a low power content addressable memory which allows search operation at high speed can be realized.Type: ApplicationFiled: November 21, 2003Publication date: November 29, 2007Inventors: Satoru Hanzawa, Junji Shigeta, Shinichiro Kimura, Takeshi Sakata, Riichiro Takemura, Kazuhiko Kajigaya
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Patent number: 7298662Abstract: A synchronous DRAM is provided which includes arrangements for operations of power supply circuitry based upon whether the DRAM is in a power down mode or not. In one embodiment, a first power supply circuit and a second power supply circuit are provided which both receive externally supplied voltages and output internal supply voltages. The first power supply circuit is not in operation when a semiconductor device of the synchronous DRAM is in a power down mode. However, the second power supply circuit is continuously in operation during the power down mode. In another arrangement, the operation of a voltage limiter circuit is controlled based on whether or not the DRAM is in a power down mode.Type: GrantFiled: July 11, 2006Date of Patent: November 20, 2007Assignee: Hitachi, Ltd.Inventors: Masashi Horiguchi, Masayuki Nakamura, Sadayuki Ohkuma, Kazuhiko Kajigaya, Yoshinobu Nakagome
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Patent number: 7289346Abstract: In a large scale integrated DRAM in pursuit of micro fabrication, data line-word line coupling capacitances are unbalanced between paired data lines. An imbalance in data line-word line means generation of large noise when the data lines are subjected to amplification, which is highly likely invite deterioration of very small signals on the data lines and erroneous amplification of data. One or a few each of a plurality of word lines connected to a plurality of memory cells connected to one data line are alternately connected to subword driver arrays arranged on the opposing sides of a memory array. Positive and negative word line noise components cancel each other in the subword drivers when the data lines are subjected to amplification, so that the word line noise can be reduced. Therefore, signals read out by sense amplifiers can be prevented from deterioration thereby to increase the reliability of memory operation.Type: GrantFiled: February 9, 2006Date of Patent: October 30, 2007Assignee: Elpida Memory, Inc.Inventors: Tomonori Sekiguchi, Riichiro Takemura, Kazuhiko Kajigaya, Katsutaka Kimura, Tsugio Takahashi
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Publication number: 20070242535Abstract: A semiconductor memory device formed on a semiconductor chip includes first memory arrays, a plurality of second memory arrays, a first voltage generator, and first bonding pads. The semiconductor chip is divided into first, second and third rectangle regions and the third rectangle region is arranged between the first rectangle region and the second rectangle region. The first memory arrays are formed in the first rectangle region. The second memory arrays are formed in the second rectangle region. The voltage generator and first bonding pads are arranged in the third rectangle region. The first bonding pads are arranged between the first rectangle region and the voltage generator and no bonding pads are arranged between the voltage generator and the second memory arrays.Type: ApplicationFiled: March 7, 2007Publication date: October 18, 2007Inventors: Kazuhiko Kajigaya, Kazuyuki Miyazawa, Manabu Tsunozaki, Kazuyoshi Oshima, Takashi Yamazaki, Yuji Sakai, Jiro Sawada, Yasunori Yamaguchi, Tetsurou Matsumoto, Shinji Udo, Hiroshi Yoshioka, Hirokazu Saito, Mitsuhiro Takano, Makoto Morino, Sinichi Miyatake, Eiji Miyamoto, Yasuhiro Kasama, Akira Endo, Ryoichi Hori, Jun Etoh, Masashi Horiguchi, Shinichi Ikenaga, Atsushi Kumata
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Patent number: 7274613Abstract: A dynamic RAM incorporates a plurality of dynamic memory cells, each of which comprises a MOSFET having a gate set as a select terminal, one source and drain set as input/output terminals, and the other source and drain connected to storage nodes of a capacitor, a plurality of word lines respectively connected to the select terminals of the plurality of dynamic memory cells, a plurality of complementary bit line pairs respectively connected to the input/output terminals of the plurality of dynamic memory cells, and a sense amplifier array comprising a plurality of latch circuits which respectively amplify differences in voltage between the complementary bit line pairs placed so as to extend in directions opposite to each other from each pair of input/output terminals. Power supply lines are provided in mesh form inclusive of a portion above word drivers.Type: GrantFiled: August 8, 2005Date of Patent: September 25, 2007Assignee: Elpida Memory, Inc.Inventors: Tomonori Sekiguchi, Kazuhiko Kajigaya, Katsutaka Kimura, Riichiro Takemura, Tsugio Takahashi, Yoshitaka Nakamura