Patents by Inventor Takahiro Watai
Takahiro Watai 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: 7857505Abstract: A method and circuit for preventing an output signal, which has been corrected through digital correction or analog correction, from deviating from a target value and for preventing power supply noise and power consumption from increasing. A sensor amplification circuit receives output of a sensor as an input signal. Correction points are set at predetermined temperature intervals. The sensor amplification circuit performs digital correction for correcting the input signal with correction data set for each correction point. Further, the sensor amplification circuit performs a second correction for correcting the input signal between the correction points with gradient data calculated from the correction data for two of the correction points that are adjacent to each other.Type: GrantFiled: November 14, 2006Date of Patent: December 28, 2010Assignee: Fujitsu Semiconductor LimitedInventors: Hiroyuki Sakima, Koju Aoki, Takahiro Watai, Masaya Mizutani, Takuya Okajima
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Patent number: 7795978Abstract: One aspect of the embodiments relates to a programmable gain circuit including an amplification unit amplifying an input signal, an input resistor coupled to an input terminal of the amplification unit, a feedback resistor coupled between an output terminal of the amplification unit and the input terminal of the amplification unit, a first switch switching a resistance value of the feedback resistor, a second switch switching a resistance value of the input resistor, and a control unit controlling the second switch such that the second switch switches the resistance value of the input resistor when the first switch switches the resistance value of the feedback resistor.Type: GrantFiled: September 19, 2008Date of Patent: September 14, 2010Assignee: Fujitsu Semiconductor LimitedInventor: Takahiro Watai
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Publication number: 20090079501Abstract: One aspect of the embodiments relates to a programmable gain circuit including an amplification unit amplifying an input signal, an input resistor coupled to an input terminal of the amplification unit, a feedback resistor coupled between an output terminal of the amplification unit and the input terminal of the amplification unit, a first switch switching a resistance value of the feedback resistor, a second switch switching a resistance value of the input resistor, and a control unit controlling the second switch such that the second switch switches the resistance value of the input resistor when the first switch switches the resistance value of the feedback resistor.Type: ApplicationFiled: September 19, 2008Publication date: March 26, 2009Applicant: FUJITSU MICROELECTRONICS LIMITEDInventor: Takahiro Watai
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Patent number: 7345536Abstract: An amplifier circuit which is connected to a sensor and variably sets an amplification property and a control method thereof are disclosed, the circuit having the capability of restricting the influence of change with time and temperature change. The amplifier circuit 1, which receives, as an input, a detection signal from the sensor and variably sets an amplification property, comprises: (1) a first reference value retaining unit 50 for retaining a first reference value K1 for setting an amplification property which makes an output signal be a specified detection reference output voltage when a reference input condition KJ is detected; (2) a correction signal generation unit 30 for generating a correction signal HS which reduces the difference between an amplification property actual measurement value and an amplification property set value; and (3) a first amplification property correction unit 40 for correcting the first reference value K1 based on the correction signal HS.Type: GrantFiled: July 15, 2005Date of Patent: March 18, 2008Assignee: Fujitsu LimitedInventors: Masaya Mizutani, Koju Aoki, Takahiro Watai, Koji Takekawa, Hiroyuki Sakima
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Patent number: 7336107Abstract: This invention provides a comparator circuit which outputs a stable waveform without oscillation even if a gradient of a change of a comparison input signal is small and determines a magnitude of the comparison input signal within a predetermined threshold value regardless of the increase/decrease direction of the comparison input signal.Type: GrantFiled: April 6, 2006Date of Patent: February 26, 2008Assignee: Fujitsu LimitedInventors: Koji Takekawa, Takahiro Watai, Masaya Mizutani, Takuya Okajima
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Publication number: 20080012718Abstract: An amplifier 1 is arranged to amplify a sense signal from a sensor with low current consumption while maintaining sufficient sensitivity. The amplifier 1 comprises a detection circuit 2 which detects a signal level of the sense signal and outputs an alarm signal when the sense signal is in a first signal level range R1, and a variable gain amplifier 3 which, based on a detection result of the detection circuit 2, stops an amplifying operation when the sense signal is in the first signal level range R1, performs the amplifying operation at a first gain G1 when the sense signal is in a second signal level range R2, or performs the amplifying operation at a second gain G2 larger than the first gain G1 when the sense signal is in a third signal level range R3 defined between the first and second signal level ranges.Type: ApplicationFiled: June 20, 2007Publication date: January 17, 2008Inventors: Kouju Aoki, Takahiro Watai, Hiroyuki Sakima, Masaya Mizutani, Takuya Okajima
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Publication number: 20070229120Abstract: A temperature characteristic correction method enabling easy setting of correction points, while reducing deviations of an output signal from a target value and preventing power supply noise and power consumption from increasing. The method includes storing correction patterns, each of which includes correction points set at a temperature interval that differs between the correction patterns. The method further includes storing correction data for each correction point in each correction pattern, selecting a correction pattern corresponding to the temperature dependent characteristic of the input signal from the correction patterns, and correcting the temperature dependent characteristic of the input signal with the selected correction pattern and the correction data corresponding to the selected correction pattern.Type: ApplicationFiled: August 29, 2006Publication date: October 4, 2007Inventors: Takuya Okajima, Koju Aoki, Takahiro Watai, Masaya Mizutani, Hiroyuki Sakima
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Publication number: 20070214884Abstract: A method and circuit for preventing an output signal, which has been corrected through digital correction or analog correction, from deviating from a target value and for preventing power supply noise and power consumption from increasing. A sensor amplification circuit receives output of a sensor as an input signal. Correction points are set at predetermined temperature intervals. The sensor amplification circuit performs digital correction for correcting the input signal with correction data set for each correction point. Further, the sensor amplification circuit performs a second correction for correcting the input signal between the correction points with gradient data calculated from the correction data for two of the correction points that are adjacent to each other.Type: ApplicationFiled: November 14, 2006Publication date: September 20, 2007Inventors: Hiroyuki Sakima, Koju Aoki, Takahiro Watai, Masaya Mizutani, Takuya Okajima
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Patent number: 7271595Abstract: Provided are two monitor circuits for monitoring two input signals of an input stage differential amplifier, respectively, and two monitor circuit for monitoring two output signals of the input stage differential amplifier, respectively. When failure occurs at the bridge circuit of a sensor element or at the input stage differential amplifier, the monitoring units or the monitoring units detect abnormality, which makes it possible to detect the failure of the sensor element or the input stage differential amplifier. Therefore it is possible to detect failure such as a disconnection or a short circuit of the bridge circuit of the sensor element and failure which has occurred at the amplifier for amplifying outputs of the sensor element.Type: GrantFiled: February 27, 2006Date of Patent: September 18, 2007Assignee: Fujitsu LimitedInventors: Katsuya Shimizu, Hiroyuki Sakima, Takahiro Watai, Masaya Mizutani, Koju Aoki, Koji Takekawa
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Publication number: 20070146015Abstract: This invention provides a comparator circuit which outputs a stable waveform without oscillation even if a gradient of a change of a comparison input signal is small and determines a magnitude of the comparison input signal within a predetermined threshold value regardless of the increase/decrease direction of the comparison input signal.Type: ApplicationFiled: April 6, 2006Publication date: June 28, 2007Inventors: Koji Takekawa, Takahiro Watai, Masaya Mizutani, Takuya Okajima
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Publication number: 20070115005Abstract: Provided are two monitor circuits for monitoring two input signals of an input stage differential amplifier, respectively, and two monitor circuit for monitoring two output signals of the input stage differential amplifier, respectively. When failure occurs at the bridge circuit of a sensor element or at the input stage differential amplifier, the monitoring units or the monitoring units detect abnormality, which makes it possible to detect the failure of the sensor element or the input stage differential amplifier. Therefore it is possible to detect failure such as a disconnection or a short circuit of the bridge circuit of the sensor element and failure which has occurred at the amplifier for amplifying outputs of the sensor element.Type: ApplicationFiled: February 27, 2006Publication date: May 24, 2007Inventors: Katsuya Shimizu, Hiroyuki Sakima, Takahiro Watai, Masaya Mizutani, Koju Aoki, Koji Takekawa
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Publication number: 20060208795Abstract: An amplifier circuit which is connected to a sensor and variably sets an amplification property and a control method thereof are disclosed, the circuit having the capability of restricting the influence of change with time and temperature change. The amplifier circuit 1, which receives, as an input, a detection signal from the sensor and variably sets an amplification property, comprises: (1) a first reference value retaining unit 50 for retaining a first reference value K1 for setting an amplification property which makes an output signal be a specified detection reference output voltage when a reference input condition KJ is detected; (2) a correction signal generation unit 30 for generating a correction signal HS which reduces the difference between an amplification property actual measurement value and an amplification property set value; and (3) a first amplification property correction unit 40 for correcting the first reference value K1 based on the correction signal HS.Type: ApplicationFiled: July 15, 2005Publication date: September 21, 2006Inventors: Masaya Mizutani, Koju Aoki, Takahiro Watai, Koji Takekawa, Hiroyuki Sakima
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Patent number: 5684874Abstract: A ringtrip judging circuit includes a single comparator for comparing a detection value of a ringing current with a threshold value and for outputting the result of the comparison, a threshold value control circuit for supplying the threshold value to the comparator, and a judging circuit for judging ringtrip based on the output of the comparator. During a prescribed period after ringing signal transmission, the threshold value control circuit changes the threshold value in a steplike manner in accordance with the result of the comparison, thereby determining a threshold value greater than a peak value during the prescribed period, and based on it, determines a threshold value for ringtrip judgement and supplies it to the comparator.Type: GrantFiled: November 13, 1995Date of Patent: November 4, 1997Assignee: Fujitsu LimitedInventors: Tetsuo Yagyu, Takahiro Watai, Hirokazu Tanaka, Tetsuji Funaki, Kunihiko Gotoh
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Patent number: 5663673Abstract: An output circuit, for minimizing output idle current fluctuations and improve the output voltage range, has first and second transistors connected to first and second power sources, with a plurality of diodes connected to control terminals of the first and second transistors. The output circuit further includes a third transistor having a first terminal connected to the second power source and a second terminal connected to a predetermined position among the plurality of diodes. A predetermined voltage is applied from the diodes to the control terminal of the first transistor when the third transistor is saturated, to bring a level of an output of said output circuit close to a level of the second power source. A fourth transistor, a fifth transistor, a first resistor, and a capacitor are also provided.Type: GrantFiled: March 30, 1995Date of Patent: September 2, 1997Assignee: Fujitsu LimitedInventors: Hirokazu Tanaka, Tatsuo Kumano, Tetsuji Funaki, Takahiro Watai