Patents by Inventor Tetsuo Chato
Tetsuo Chato 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: 7545156Abstract: The test circuit according to the present invention includes: a plurality of light-receiving elements; a plurality of amplifiers, each of which converts, into a voltage, a photoelectric current supplied from one of the light-receiving elements; and an electric current supplying unit which supplies an electric current to each of the light-receiving elements and each of the amplifiers.Type: GrantFiled: February 21, 2007Date of Patent: June 9, 2009Assignee: Panasonic CorporationInventors: Yousuke Kuroiwa, Hideo Fukuda, Hiroshi Yamaguchi, Tetsuo Chato, Yuzo Shimizu, Masaki Taniguchi
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Patent number: 7449670Abstract: An amplifier circuit according to the present invention includes: a first operational amplifier having a negative input terminal, a positive input terminal, and an output terminal; a photodiode connected to the negative input terminal; a first resistor inserted between the output terminal and the negative input terminal; and a second resistor inserted between the output terminal and the positive input terminal, in which the amplifier circuit outputs current from the output terminal via the second resistor.Type: GrantFiled: March 19, 2007Date of Patent: November 11, 2008Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hiroshi Yamaguchi, Shinichi Miyamoto, Tetsuo Chato, Yasufumi Shirakawa, Yuzo Shimizu
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Patent number: 7408141Abstract: The present invention provides a light-receiving amplifier circuit which includes a clipping circuit, can prevent an oscillation at the time of clipping operation, and can freely set clipping voltage. The light-receiving circuit of the present invention includes a photodiode, an operation amplifier, a conversion resistance connected between an output terminal and an inverting input terminal of the operation amplifier, and a clipping circuit which clips output voltage of the operation amplifier to a predetermined value. The clipping circuit includes a PNP transistor which detects a change in the output voltage of the operation amplifier and a voltage source connected to a base of the PNP transistor. Here, when the PNP transistor is turned ON along with an increase of an emitter potential of the NPN transistor which constitutes an output amplifier stage of the operation amplifier, voltage from the voltage source is applied to the base of the NPN transistor via the PNP transistor.Type: GrantFiled: July 3, 2006Date of Patent: August 5, 2008Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Tetsuo Chato, Hiroshi Yamaguchi
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Patent number: 7298977Abstract: The present invention is intended to prevent a light-emitting diode from emitting light continuously in the case when the level at an input terminal is fixed high because of software or the like and to avoid various problems, such as battery exhaustion and breakdown of the light-emitting diode, in PDAs, cellular phones, etc. For these purposes, a high-pass filter 21 for passing the high-frequency components of an optical transmission input signal having a pulse waveform and a binary circuit 22 for binarizing the output signal of the high-pass filter 21 so as to be returned to a pulse waveform are provided in the preceding stage of a light-emitting device driving circuit 23 for driving a light-emitting diode 8 for optical transmission.Type: GrantFiled: November 28, 2002Date of Patent: November 20, 2007Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Katsuichi Ohsawa, Toyoyuki Shimazaki, Tetsuo Chato, Yuzo Shimizu, Kenji Imaizumi
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Publication number: 20070252602Abstract: The test circuit according to the present invention includes: a plurality of light-receiving elements; a plurality of amplifiers, each of which converts, into a voltage, a photoelectric current supplied from one of the light-receiving elements; and an electric current supplying unit which supplies an electric current to each of the light-receiving elements and each of the amplifiers.Type: ApplicationFiled: February 21, 2007Publication date: November 1, 2007Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.Inventors: Yousuke KUROIWA, Hideo FUKUDA, Hiroshi YAMAGUCHI, Tetsuo CHATO, Yuzo SHIMIZU, Masaki TANIGUCHI
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Publication number: 20070228258Abstract: An amplifier circuit according to the present invention includes: a first operational amplifier having a negative input terminal, a positive input terminal, and an output terminal; a photodiode connected to the negative input terminal; a first resistor inserted between the output terminal and the negative input terminal; and a second resistor inserted between the output terminal and the positive input terminal, in which the amplifier circuit outputs current from the output terminal via the second resistor.Type: ApplicationFiled: March 19, 2007Publication date: October 4, 2007Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.Inventors: Hiroshi Yamaguchi, Shinichi Miyamoto, Tetsuo Chato, Yasufumi Shirakawa, Yuzo Shimizu
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Publication number: 20070018079Abstract: The present invention provides a light-receiving amplifier circuit which includes a clipping circuit, can prevent an oscillation at the time of clipping operation, and can freely set clipping voltage. The light-receiving circuit of the present invention includes a photodiode, an operation amplifier, a conversion resistance connected between an output terminal and an inverting input terminal of the operation amplifier, and a clipping circuit which clips output voltage of the operation amplifier to a predetermined value. The clipping circuit includes a PNP transistor which detects a change in the output voltage of the operation amplifier and a voltage source connected to a base of the PNP transistor. Here, when the PNP transistor is turned ON along with an increase of an emitter potential of the NPN transistor which constitutes an output amplifier stage of the operation amplifier, voltage from the voltage source is applied to the base of the NPN transistor via the PNP transistor.Type: ApplicationFiled: July 3, 2006Publication date: January 25, 2007Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.Inventors: Tetsuo Chato, Hiroshi Yamaguchi
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Publication number: 20050063710Abstract: The present invention is intended to prevent a light-emitting diode from emitting light continuously in the case when the level at an input terminal is fixed high because of software or the like and to avoid various problems, such as battery exhaustion and breakdown of the light-emitting diode, in PDAs, cellular phones, etc. For these purposes, a high-pass filter 21 for passing the high-frequency components of an optical transmission input signal having a pulse waveform and a binary circuit 22 for binarizing the output signal of the high-pass filter 21 so as to be returned to a pulse waveform are provided in the preceding stage of a light-emitting device driving circuit 23 for driving a light-emitting diode 8 for optical transmission.Type: ApplicationFiled: November 28, 2002Publication date: March 24, 2005Applicant: Matsushita Electric Industrial Co., Ltd.Inventors: Katsuichi Ohsawa, Toyoyuki Shimazaki, Tetsuo Chato, Yuzo Shimizu, Kenji Imaizumi
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Patent number: 6700144Abstract: A semiconductor device includes the following: a semiconductor substrate of a first conduction type; an intrinsic semiconductor layer of the first conduction type formed on the semiconductor substrate; a first semiconductor layer of a second conduction type formed on the intrinsic semiconductor layer; a first impurity layer of the first conduction type formed in the first semiconductor layer of the second conduction type; and a bipolar transistor and a MIS transistor formed in the first semiconductor layer of the second conduction type. The laminated structure of the semiconductor substrate, the intrinsic semiconductor layer, and the first semiconductor layer provides a diode for photoelectric conversion. A first insulator layer and a second insulator layer are formed respectively in at least a portion below the bipolar transistor and the MIS transistor.Type: GrantFiled: May 24, 2002Date of Patent: March 2, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Toyoyuki Shimazaki, Katuichi Ohsawa, Tetsuo Chato, Yuzo Shimizu
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Publication number: 20020182801Abstract: A semiconductor device includes the following: a semiconductor substrate of a first conduction type; an intrinsic semiconductor layer of the first conduction type formed on the semiconductor substrate; a first semiconductor layer of a second conduction type formed on the intrinsic semiconductor layer; a first impurity layer of the first conduction type formed in the first semiconductor layer of the second conduction type; and a bipolar transistor and a MIS transistor formed in the first semiconductor layer of the second conduction type. The laminated structure of the semiconductor substrate, the intrinsic semiconductor layer, and the first semiconductor layer provides a diode for photoelectric conversion. A first insulator layer and a second insulator layer are formed respectively in at least a portion below the bipolar transistor and the MIS transistor.Type: ApplicationFiled: May 24, 2002Publication date: December 5, 2002Applicant: Matsushita Electric Industrial Co., LtdInventors: Toyoyuki Shimazaki, Katuichi Ohsawa, Tetsuo Chato, Yuzo Shimizu