Patents by Inventor Kiyoo Itoh
Kiyoo Itoh 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: 10319430Abstract: A memory includes a plurality of memory cells and a plurality of peripheral circuits. Each memory cell has a first inverter and a second inverter, the first inverter is supplied by a first power supply rail and a second power supply rail, and the second inverter is supplied by a third power supply rail and a fourth power supply rail. A first voltage difference is applied across the first power supply rail and the second power supply rail, a second voltage difference is applied across the third power supply rail and the fourth power supply rail, and the first voltage difference is less than the second voltage difference. The plurality of peripheral circuits use at least one of boosted power supplies corresponding to the second voltage difference and gate-source differentially-driven circuits.Type: GrantFiled: August 24, 2017Date of Patent: June 11, 2019Assignee: Etron Technology, Inc.Inventor: Kiyoo Itoh
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Patent number: 10141047Abstract: A static random access memory (SRAM) comprises a plurality of memory cells each having a pair of cross-coupled inverters, a first of the inverters being supplied by first and second power supply rails and a second of the inverters being supplied by third and fourth supply rails, an input of the second inverter being coupled to a first bit line via a first transistor; and a power supply circuit adapted to apply a first voltage difference across the first and second power supply rails and a second voltage difference across the third and fourth power supply rails, the second voltage difference being greater than the first voltage difference.Type: GrantFiled: May 20, 2016Date of Patent: November 27, 2018Assignee: COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIESInventors: Kiyoo Itoh, Amara Amara, Khaja Ahmad Shaik
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Publication number: 20180061486Abstract: A memory includes a plurality of memory cells and a plurality of peripheral circuits. Each memory cell has a first inverter and a second inverter, the first inverter is supplied by a first power supply rail and a second power supply rail, and the second inverter is supplied by a third power supply rail and a fourth power supply rail. A first voltage difference is applied across the first power supply rail and the second power supply rail, a second voltage difference is applied across the third power supply rail and the fourth power supply rail, and the first voltage difference is less than the second voltage difference. The plurality of peripheral circuits use at least one of boosted power supplies corresponding to the second voltage difference and gate-source differentially-driven circuits.Type: ApplicationFiled: August 24, 2017Publication date: March 1, 2018Inventor: Kiyoo Itoh
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Publication number: 20160372180Abstract: The invention concerns a static random access memory (SRAM) comprising: a plurality of memory cells each having a pair of cross-coupled inverters (102, 104), a first of the inverters (102) being supplied by first and second power supply rails (VDD, VSS) and a second of the inverters (104) being supplied by third and fourth supply rails (114, 116), an input of the second inverter (102) being coupled to a first bit line (BL, WBL) via a first transistor (118); and a power supply circuit (120) adapted to apply a first voltage difference (VDD) across the first and second power supply rails (VDD, VSS) and a second voltage difference (VDH, VSL) across the third and fourth power supply rails (114, 116), the second voltage difference being greater than the first voltage difference.Type: ApplicationFiled: May 20, 2016Publication date: December 22, 2016Inventors: Amara AMARA, Kiyoo ITOH, Khaja Ahmad SHAIK
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Patent number: 8964478Abstract: A semiconductor device includes a sense amplifier circuit. The sense amplifier circuit includes a cross-coupled first transistor and second transistor that perform amplification. The sources of the cross-coupled transistors are respectively connected in series with a third transistor and a fourth transistor, and electrical current supply capability of the third and fourth transistors is controlled by a control voltage given to control electrodes of the third and fourth transistors. In a data retaining period, a minimum sub-threshold current necessary for retaining the data is flowed to the third and fourth transistors according to the control voltage, and bit line potential is maintained.Type: GrantFiled: May 23, 2013Date of Patent: February 24, 2015Assignee: PS4 Luxco S.a.r.l.Inventors: Shinichi Takayama, Akira Kotabe, Kiyoo Itoh, Tomonori Sekiguchi
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Patent number: 8750032Abstract: The disclosed semiconductor recording device achieves multi-valued reading and writing using a spin-injection magnetization-reversal tunneling magnetoresistive element (TMR element). A first current that has at least the same value as that of the element requiring the highest current to reverse the magnetization thereof among a plurality of TMR elements is, in the direction that causes reversal to either a parallel state or an anti-parallel state, applied to a memory cell having the plurality of TMR elements, and then a second current which is in the reverse direction from the first current and of which only the value needed to reverse the magnetoresistance state of at least one TMR element excluding the element requiring the maximum current among the plurality of TMR elements is applied to each, and multi-valued writing is performed.Type: GrantFiled: April 5, 2011Date of Patent: June 10, 2014Assignee: Hitachi, Ltd.Inventors: Takayuki Kawahara, Riichiro Takemura, Takashi Ishigaki, Kiyoo Itoh
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Patent number: 8552796Abstract: A CMOS circuit and a semiconductor device having small leakage current and a low threshold voltage, and which is operated at high speed and with a small voltage amplitude, including an output stage circuit having MOSTs configured such that when their gates and sources are respectively set to an equal voltage, subthreshold leakage currents substantially flow between their drains and sources, and upon deactivation, a voltage is applied to the gate of each of the MOSTs to cause a reverse bias to be applied between the gate and source of the MOST. Upon activation of the circuit, the MOST is held in a reverse bias state or controlled to a forward bias state according to an input voltage.Type: GrantFiled: September 12, 2012Date of Patent: October 8, 2013Assignee: Renesas Electronics CorporationInventors: Kiyoo Itoh, Masanao Yamaoka
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Publication number: 20130258793Abstract: A semiconductor device includes a sense amplifier circuit. The sense amplifier circuit includes a cross-coupled first transistor and second transistor that perform amplification. The sources of the cross-coupled transistors are respectively connected in series with a third transistor and a fourth transistor, and electrical current supply capability of the third and fourth transistors is controlled by a control voltage given to control electrodes of the third and fourth transistors. In a data retaining period, a minimum sub-threshold current necessary for retaining the data is flowed to the third and fourth transistors according to the control voltage, and bit line potential is maintained.Type: ApplicationFiled: May 23, 2013Publication date: October 3, 2013Applicant: ELPIDA MEMORY, INC.Inventors: Shinichi TAKAYAMA, Akira KOTABE, Kiyoo ITOH, Tomonori SEKIGUCHI
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Patent number: 8472273Abstract: A semiconductor device includes a sense amplifier circuit. The sense amplifier circuit includes a cross-coupled first transistor and second transistor that perform amplification. The sources of the cross-coupled transistors are respectively connected in series with a third transistor and a fourth transistor, and electrical current supply capability of the third and fourth transistors is controlled by a control voltage given to control electrodes of the third and fourth transistors. In a data retaining period, a minimum sub-threshold current necessary for retaining the data is flowed to the third and fourth transistors according to the control voltage, and bit line potential is maintained.Type: GrantFiled: May 27, 2011Date of Patent: June 25, 2013Assignee: Elpida Memory, Inc.Inventors: Shinichi Takayama, Akira Kotabe, Kiyoo Itoh, Tomonori Sekiguchi
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Patent number: 8427864Abstract: To write information on a memory cell of SPRAM formed of an MOS transistor and a tunnel magnetoresistive element, the memory cell is supplied with a current in a direction opposite to a direction of a current required for writing the information on the memory cell, and then, the memory cell is supplied with a current required for writing. In this manner, even when the same information is sequentially written on the memory cell, since the currents in the two directions are caused to flow in pairs in the tunnel magnetoresistive element of the memory cell each time information is rewritten, deterioration of a film that forms the tunnel magnetoresistive element can be suppressed. Therefore, reliability of the SPRAM can be improved.Type: GrantFiled: June 2, 2010Date of Patent: April 23, 2013Assignee: Hitachi, Ltd.Inventors: Takayuki Kawahara, Kiyoo Itoh, Riichiro Takemura, Kenchi Ito
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Publication number: 20130063200Abstract: A CMOS circuit and a semiconductor device having small leakage current and a low threshold voltage, and which is operated at high speed and with a small voltage amplitude, including an output stage circuit having MOSTs configured such that when their gates and sources are respectively set to an equal voltage, subthreshold leakage currents substantially flow between their drains and sources, and upon deactivation, a voltage is applied to the gate of each of the MOSTs to cause a reverse bias to be applied between the gate and source of the MOST. Upon activation of the circuit, the MOST is held in a reverse bias state or controlled to a forward bias state according to an input voltage.Type: ApplicationFiled: September 12, 2012Publication date: March 14, 2013Inventors: Kiyoo Itoh, Masanao Yamaoka
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Publication number: 20130051134Abstract: The disclosed semiconductor recording device achieves multi-valued reading and writing using a spin-injection magnetization-reversal tunneling magnetoresistive element (TMR element). A first current that has at least the same value as that of the element requiring the highest current to reverse the magnetization thereof among a plurality of TMR elements is, in the direction that causes reversal to either a parallel state or an anti-parallel state, applied to a memory cell having the plurality of TMR elements, and then a second current which is in the reverse direction from the first current and of which only the value needed to reverse the magnetoresistance state of at least one TMR element excluding the element requiring the maximum current among the plurality of TMR elements is applied to each, and multi-valued writing is performed.Type: ApplicationFiled: April 5, 2011Publication date: February 28, 2013Inventors: Takayuki Kawahara, Riichiro Takemura, Takashi Ishigaki, Kiyoo Itoh
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Patent number: 8325553Abstract: A static memory cell, composed of cross-coupled MOS transistors having a relatively high threshold voltage, is equipped with MOS transistors for controlling the power supply line voltage of the memory cell. To permit the voltage difference between two data storage nodes in the inactivated memory cell to exceed the voltage difference between the two nodes when write data is applied from a data line pair DL and /DL to the two nodes in the activated memory cell, the power supply line voltage control transistors are turned on to apply a high voltage VCH to the power supply lines after the word line voltage is turned off. The data holding voltage in the memory cell can be activated to a high voltage independent of the data line voltage, and the data holding voltage can be dynamically set so that read and write operations can be performed at high speed with low power consumption.Type: GrantFiled: June 7, 2011Date of Patent: December 4, 2012Assignee: Renesas Electronics CorporationInventors: Kiyoo Itoh, Koichiro Ishibashi
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Patent number: 8294510Abstract: There is provided an output stage circuit including such MOSTs (M) that when their gates and sources are respectively set to an equal voltage, subthreshold leakage currents substantially flow between their drains and sources, wherein upon its deactivation, a voltage is applied to the gate of each of the MOSTs (M) in such a manner than a reverse bias is applied between the gate and source of the MOST (M). That is, when the MOST (M) is of a p channel type, a voltage higher than that of a p type source is applied to its gate. When the MOST (M) is of an n channel type, a voltage lower than that of an n type source is applied to its gate. Upon activation of the circuit, the MOST is held in a reverse bias state or controlled to a forward bias state according to an input voltage. A CMOS circuit and a semiconductor device can be realized each of which is small in leakage current even though its threshold voltage is low and which is operated at high speed and with a small voltage amplitude.Type: GrantFiled: December 11, 2007Date of Patent: October 23, 2012Assignee: Renesas Electronics CorporationInventors: Kiyoo Itoh, Masanao Yamaoka
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Publication number: 20120081952Abstract: To write information on a memory cell of SPRAM formed of an MOS transistor and a tunnel magnetoresistive element, the memory cell is supplied with a current in a direction opposite to a direction of a current required for writing the information on the memory cell, and then, the memory cell is supplied with a current required for writing. In this manner, even when the same information is sequentially written on the memory cell, since the currents in the two directions are caused to flow in pairs in the tunnel magnetoresistive element of the memory cell each time information is rewritten, deterioration of a film that forms the tunnel magnetoresistive element can be suppressed. Therefore, reliability of the SPRAM can be improved.Type: ApplicationFiled: June 2, 2010Publication date: April 5, 2012Inventors: Takayuki Kawahara, Kiyoo Itoh, Riichiro Takemura, Kenchi Ito
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Patent number: 8106678Abstract: A semiconductor device including first and second power lines, and first and second circuit blocks coupled between the power lines. A first switching element is inserted between the first circuit block and at least one of the power lines and a second switching element is inserted between the second circuit block and at least one of the power lines. The first switching element is rendered conductive to allow the first circuit block to receive the power voltage through the first and second power lines while the second switching element is rendered nonconductive to prevent the second circuit block from receiving the power voltage through the first and second power lines, so that a leakage current flowing through the second circuit is suppressed.Type: GrantFiled: December 23, 2009Date of Patent: January 31, 2012Assignee: Elpida Memory, Inc.Inventors: Takeshi Sakata, Kiyoo Itoh, Masashi Horiguchi
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Publication number: 20110292709Abstract: A semiconductor device includes a sense amplifier circuit. The sense amplifier circuit includes a cross-coupled first transistor and second transistor that perform amplification. The sources of the cross-coupled transistors are respectively connected in series with a third transistor and a fourth transistor, and electrical current supply capability of the third and fourth transistors is controlled by a control voltage given to control electrodes of the third and fourth transistors. In a data retaining period, a minimum sub-threshold current necessary for retaining the data is flowed to the third and fourth transistors according to the control voltage, and bit line potential is maintained.Type: ApplicationFiled: May 27, 2011Publication date: December 1, 2011Applicant: ELPIDA MEMORY, INC.Inventors: Shinichi TAKAYAMA, Akira KOTABE, Kiyoo ITOH, Tomonori SEKIGUCHI
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Patent number: 8035147Abstract: A high-speed and low-voltage DRAM memory cell capable of operating at 1 V or less and an array peripheral circuit are provided. A DRAM cell is comprised of a memory cell transistor and planar capacitor which utilize a FD-SOI MOST structure. Since there is no junction leakage current, loss of stored charge is eliminated, and the low-voltage operation can be realized. Further, a gate and a well in a cross-coupled type sense amplifier using FD-SOI MOSTs are connected. By this means, a threshold value dynamically changes and high-speed sensing operation can be realized.Type: GrantFiled: April 27, 2010Date of Patent: October 11, 2011Assignee: Hitachi, Ltd.Inventors: Kiyoo Itoh, Riichiro Takemura
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Publication number: 20110235439Abstract: A static memory cell, composed of cross-coupled MOS transistors having a relatively high threshold voltage, is equipped with MOS transistors for controlling the power supply line voltage of the memory cell. To permit the voltage difference between two data storage nodes in the inactivated memory cell to exceed the voltage difference between the two nodes when write data is applied from a data line pair DL and /DL to the two nodes in the activated memory cell, the power supply line voltage control transistors are turned on to apply a high voltage VCH to the power supply lines after the word line voltage is turned off. The data holding voltage in the memory cell can be activated to a high voltage independent of the data line voltage, and the data holding voltage can be dynamically set so that read and write operations can be performed at high speed with low power consumption.Type: ApplicationFiled: June 7, 2011Publication date: September 29, 2011Applicant: RENESAS ELECTRONICS CORPORATIONInventors: Kiyoo Itoh, Koichiro Ishibashi
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Patent number: 7990208Abstract: In a semiconductor integrated circuit device, a circuit block has a first MOS transistor, and a leakage current control circuit having a second MOS transistor and a current source, a source and drain circuit of the second MOS transistor is formed between the power supply line of the circuit block and a voltage point where operating voltage is supplied. This current source is connected to the power supply line and in a first state, the power supply line is driven to a first voltage by the second MOS transistor. In a second state, the power supply line is controlled at a second voltage by current flow in the current source and, the voltage applied across the source and drain of the first MOS transistor in the second state is smaller than the voltage applied across the source and drain of the first MOS transistor in the first state.Type: GrantFiled: November 10, 2009Date of Patent: August 2, 2011Assignee: Renesas Electronics CorporationInventors: Hiroyuki Mizuno, Kiyoo Itoh