Patents by Inventor Shoichi Kokubo
Shoichi Kokubo 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: 7193882Abstract: To shorten the time of a test for detecting deteriorated capacitors, a semiconductor memory device having a 2T2C type memory cell structure is designed in such a way that a voltage VBL of a bit line pair which determines a voltage to be applied to ferroelectric memory cells and a voltage VPL of plate lines are so set as to satisfy a relationship of VBL=VPL<VDD where VDD is a supply voltage. This makes the size of the hysteresis loop of the ferroelectric capacitors smaller than that in case of VBL=VPL=VDD, a potential difference ?V between data “0” and data “1” can be made smaller than an operational margin of a sense amplifier. This makes it possible to detect a deteriorated ferroelectric capacitor without conducting a cycling test.Type: GrantFiled: December 29, 2005Date of Patent: March 20, 2007Assignee: Oki Electric Indusrty Co., Ltd.Inventors: Kazuhiko Takahashi, Shinzo Sakuma, Shoichi Kokubo
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Publication number: 20060120135Abstract: To shorten the time of a test for detecting deteriorated capacitors, a semiconductor memory device having a 2T2C type memory cell structure is designed in such a way that a voltage VBL of a bit line pair which determines a voltage to be applied to ferroelectric memory cells and a voltage VPL of plate lines are so set as to satisfy a relationship of VBL=VPL<VDD where VDD is a supply voltage. This makes the size of the hysteresis loop of the ferroelectric capacitors smaller than that in case of VBL=VPL=VDD, a potential difference ?V between data “0” and data “1” can be made smaller than an operational margin of a sense amplifier. This makes it possible to detect a deteriorated ferroelectric capacitor without conducting a cycling test.Type: ApplicationFiled: December 29, 2005Publication date: June 8, 2006Inventors: Kazuhiko Takahashi, Shinzo Sakuma, Shoichi Kokubo
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Patent number: 7012830Abstract: To shorten the time of a test for detecting deteriorated capacitors, a semiconductor memory device having a 2T2C type memory cell structure is designed in such a way that a voltage VBL of a bit line pair which determines a voltage to be applied to ferroelectric memory cells and a voltage VPL of plate lines are so set as to satisfy a relationship of VBL=VPL<VDD where VDD is a supply voltage. This makes the size of the hysteresis loop of the ferroelectric capacitors smaller than that in case of VBL=VPL=VDD, a potential difference ?V between data “0” and data “1” can be made smaller than an operational margin of a sense amplifier. This makes it possible to detect a deteriorated ferroelectric capacitor without conducting a cycling test.Type: GrantFiled: April 29, 2005Date of Patent: March 14, 2006Assignee: Oki Electric Industry Co., Ltd.Inventors: Kazuhiko Takahashi, Shinzo Sakuma, Shoichi Kokubo
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Publication number: 20050195628Abstract: To shorten the time of a test for detecting deteriorated capacitors, a semiconductor memory device having a 2T2C type memory cell structure is designed in such a way that a voltage VBL of a bit line pair which determines a voltage to be applied to ferroelectric memory cells and a voltage VPL of plate lines are so set as to satisfy a relationship of VBL=VPL<VDD where VDD is a supply voltage. This makes the size of the hysteresis loop of the ferroelectric capacitors smaller than that in case of VBL=VPL=VDD, a potential difference ?V between data “0” and data “1” can be made smaller than an operational margin of a sense amplifier. This makes it possible to detect a deteriorated ferroelectric capacitor without conducting a cycling test.Type: ApplicationFiled: April 29, 2005Publication date: September 8, 2005Inventors: Kazuhiko Takahashi, Shinzo Sakuma, Shoichi Kokubo
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Patent number: 6914799Abstract: To shorten the time of a test for detecting deteriorated capacitors, a semiconductor memory device having a 2T2C type memory cell structure is designed in such a way that a voltage VBL of a bit line pair which determines a voltage to be applied to ferroelectric memory cells and a voltage VPL of plate lines are so set as to satisfy a relationship of VBL=VPL<VDD where VDD is a supply voltage. This makes the size of the hysteresis loop of the ferroelectric capacitors smaller than that in case of VBL=VPL=VDD, a potential difference ?V between data “0” and data “1” can be made smaller than an operational margin of a sense amplifier. This makes it possible to detect a deteriorated ferroelectric capacitor without conducting a cycling test.Type: GrantFiled: July 15, 2004Date of Patent: July 5, 2005Assignee: Oki Electric Industry Co., Ltd.Inventors: Kazuhiko Takahashi, Shinzo Sakuma, Shoichi Kokubo
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Publication number: 20040257885Abstract: To shorten the time of a test for detecting deteriorated capacitors, a semiconductor memory device having a 2T2C type memory cell structure is designed in such a way that a voltage VBL of a bit line pair which determines a voltage to be applied to ferroelectric memory cells and a voltage VPL of plate lines are so set as to satisfy a relationship of VBL=VPL<VDD where VDD is a supply voltage. This makes the size of the hysteresis loop of the ferroelectric capacitors smaller than that in case of VBL=VPL=VDD, a potential difference &Dgr;V between data “0” and data “1” can be made smaller than an operational margin of a sense amplifier. This makes it possible to detect a deteriorated ferroelectric capacitor without conducting a cycling test.Type: ApplicationFiled: July 15, 2004Publication date: December 23, 2004Inventors: Kazuhiko Takahashi, Shinzo Sakuma, Shoichi Kokubo
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Patent number: 6781862Abstract: To shorten the time of a test for detecting deteriorated capacitors, a semiconductor memory device having a 2T2C type memory cell structure is designed in such a way that a voltage VBL of a bit line pair which determines a voltage to be applied to ferroelectric memory cells and a voltage VPL of plate lines are so set as to satisfy a relationship of VBL=VPL<VDD where VDD is a supply voltage. This makes the size of the hysteresis loop of the ferroelectric capacitors smaller than that in case of VBL=VPL=VDD, a potential difference &Dgr;V between data “0” and data “1” can be made smaller than an operational margin of a sense amplifier. This makes it possible to detect a deteriorated ferroelectric capacitor without conducting a cycling test.Type: GrantFiled: September 26, 2002Date of Patent: August 24, 2004Assignee: Oki Electric Industry Co., Ltd.Inventors: Kazuhiko Takahashi, Shinzo Sakuma, Shoichi Kokubo
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Publication number: 20030185041Abstract: To shorten the time of a test for detecting deteriorated capacitors, a semiconductor memory device having a 2T2C type memory cell structure is designed in such a way that a voltage VBL of a bit line pair which determines a voltage to be applied to ferroelectric memory cells and a voltage VPL of plate lines are so set as to satisfy a relationship of VBL=VPL<VDD where VDD is a supply voltage. This makes the size of the hysteresis loop of the ferroelectric capacitors smaller than that in case of VBL=VPL=VDD, a potential difference &Dgr;V between data “0” and data “1” can be made smaller than an operational margin of a sense amplifier. This makes it possible to detect a deteriorated ferroelectric capacitor without conducting a cycling test.Type: ApplicationFiled: September 26, 2002Publication date: October 2, 2003Inventors: Kazuhiko Takahashi, Shinzo Sakuma, Shoichi Kokubo
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Patent number: 6400263Abstract: A tire pressure monitoring system driven by a battery power source allowing radio transmission of a monitor signal of a detection value of tire pressure detected by a sensor. The transmission is to the vehicle via a transmitting section in the monitoring system. A control section in the system compares the detection value from the sensor with a set value, and based on a comparison result, controls radio transmission of the monitor signal by the transmitting section. Prior to normal radio transmission of the monitor signal, radio transmission of the monitor signal is controlled by the control section. The sensor preferably comprises a temperature sensor.Type: GrantFiled: July 20, 2000Date of Patent: June 4, 2002Assignee: Oki Electric Industry Co., Ltd.Inventor: Shoichi Kokubo
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Patent number: 5982208Abstract: A clock multiplier controls the frequency of an output clock signal according to the frequency of an input clock signal by means of two feedback loops. The first feedback loop, active during a fixed number of initial cycles of the input clock signal, counts cycles of the output clock signal during each cycle of the input clock signal, and controls the output clock frequency according to the resulting count values. The second feedback loop, used after the fixed number of initial cycles, divides the frequency of the output clock signal, and controls the output clock frequency according to the phase difference between the resulting divided signal and the input clock signal.Type: GrantFiled: January 14, 1998Date of Patent: November 9, 1999Assignee: Oki Electric Industry Co., Ltd.Inventors: Shoichi Kokubo, Mitsuhiro Watanabe