Patents by Inventor Tadao Kadowaki

Tadao Kadowaki 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).

  • Patent number: 6686792
    Abstract: A constant-voltage generation circuit 100 creates a constant voltage. This constant-voltage generation circuit 100 comprises a first voltage creation circuit 110 for creating a reference voltage and a second voltage creation circuit 130 for creating the constant voltage which has a predetermined relationship with the reference voltage. The first voltage creation circuit 110 comprises a first constant-current source 150-1 for supplying a constant current and a first voltage-control transistor 112, through which this constant current flows, for outputting the reference voltage on the basis of a predetermined potential. The constant current is set to a value within the saturated operating region of the first voltage control transistor 112.
    Type: Grant
    Filed: February 4, 2002
    Date of Patent: February 3, 2004
    Assignee: Seiko Epson Corporation
    Inventors: Shinji Nakamiya, Tadao Kadowaki, Yoshiki Makiuchi
  • Patent number: 6603175
    Abstract: A semiconductor integrated circuit comprising: a first power line which supplies a first voltage potential; a second power line which supplies a second voltage potential that is lower than the first voltage potential; a voltage regulator circuit connected electrically to the first and second power lines; a third power line which supplies a constant voltage generated by a voltage regulator circuit, with reference to the first voltage potential; and an operating circuit connected electrically to the first and third power lines. At least one transistor configuring the voltage regulator circuit is a partially-depleted SOI field-effect transistor in which a body region and a source region are connected electrically. At least one transistor configuring the operating circuit is a partially-depleted SOI field-effect transistor in which a body region is in an electrically floating state.
    Type: Grant
    Filed: May 16, 2001
    Date of Patent: August 5, 2003
    Assignee: Seiko Epson Corporation
    Inventors: Tadao Kadowaki, Akihiko Ebina, Masayuki Yamaguchi, Yoko Sato
  • Patent number: 6593823
    Abstract: An oscillation circuit including a first electrostatic protection circuit connected between a signal path of the oscillation circuit and a constant-voltage side, and bypassing an electrostatic voltage of a first polarity that intrudes into the signal path to a side of a constant bypass voltage through a first semiconductor rectifier element. A second electrostatic protection circuit is connected between the signal path and a reference potential side, and bypassing an electrostatic voltage of a second polarity that intrudes into the signal path to the reference potential side through a second semiconductor rectifier element. The constant bypass voltage is set to a value such that the first and second semiconductor rectifier elements are not turned on by voltage change in the signal path caused by a leakage current, even when a leakage current is generated between the signal path and a power-supply voltage line.
    Type: Grant
    Filed: September 26, 2001
    Date of Patent: July 15, 2003
    Assignee: Seiko Epson Corporation
    Inventors: Shinji Nakamiya, Hiroshi Yabe, Tadao Kadowaki, Yoshiki Makiuchi
  • Patent number: 6421261
    Abstract: A power supply apparatus employs a unidirectional unit equipped with a diode, a bypass switch connected in parallel to the diode, and a controller which turns the bypass switch ON when a forward voltage appears in the diode in order to rectify or prevent the backflow of the power from a power generating unit built in portable electronic equipment of an arm-worn type or the like; it is able to eliminate almost all loss caused by the forward voltage at the time of power supply. The elctromotive force of the power generating unit incorporated in arm-worn type electronic equipment ranges from almost the same level to about a few times the level of the forward voltage; hence, the use of the unidirectional unit enables rectifying efficiency to be markedly improved.
    Type: Grant
    Filed: January 26, 1999
    Date of Patent: July 16, 2002
    Assignee: Seiko Epson Corporation
    Inventors: Teruhiko Fujisawa, Hiroshi Yabe, Osamu Shinkawa, Tadao Kadowaki
  • Patent number: 6411169
    Abstract: This invention relates to a crystal oscillation circuit that oscillates stably with a low power consumption. This crystal oscillation circuit comprises an inverting amplifier, a crystal oscillator, and a feedback circuit that inverts the phase of an output from this inverting amplifier and feeds it back as an input. The sum of the absolute value of the threshold voltage of a first semiconductor switching element and the absolute value of the threshold voltage of a second semiconductor switching element is set to be greater than or equal to the absolute value of the potential difference between first and second potentials, when said inverting amplifier includes the first and second semiconductor switching elements.
    Type: Grant
    Filed: August 3, 2000
    Date of Patent: June 25, 2002
    Assignee: Seiko Epson Corporation
    Inventors: Hiroshi Yabe, Shinji Nakamiya, Tadao Kadowaki, Yoshiki Makiuchi
  • Publication number: 20020070817
    Abstract: There is provided an oscillation circuit that enables oscillation at a stable frequency, unaffected by changes in the power-supply voltage of a main power source.
    Type: Application
    Filed: September 26, 2001
    Publication date: June 13, 2002
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Shinji Nakamiya, Hiroshi Yabe, Tadao Kadowaki, Yoshiki Makiuchi
  • Publication number: 20020070792
    Abstract: A constant-voltage generation circuit 100 creates a constant voltage. This constant-voltage generation circuit 100 comprises a first voltage creation circuit 110 for creating a reference voltage and a second voltage creation circuit 130 for creating the constant voltage which has a predetermined relationship with the reference voltage. The first voltage creation circuit 110 comprises a first constant-current source 150-1 for supplying a constant current and a first voltage-control transistor 112, through which this constant current flows, for outputting the reference voltage on the basis of a predetermined potential. The constant current is set to a value within the saturated operating region of the first voltage control transistor 112.
    Type: Application
    Filed: February 4, 2002
    Publication date: June 13, 2002
    Applicant: Seiko Epson Corporation
    Inventors: Shinji Nakamiya, Tadao Kadowaki, Yoshiki Makiuchi
  • Publication number: 20020038888
    Abstract: A semiconductor integrated circuit comprising: a first power line which supplies a first voltage potential; a second power line which supplies a second voltage potential that is lower than the first voltage potential; a voltage regulator circuit connected electrically to the first and second power lines; a third power line which supplies a constant voltage generated by a voltage regulator circuit, with reference to the first voltage potential; and an operating circuit connected electrically to the first and third power lines. At least one transistor configuring the voltage regulator circuit is a partially-depleted SOI field-effect transistor in which a body region and a source region are connected electrically. At least one transistor configuring the operating circuit is a partially-depleted SOI field-effect transistor in which a body region is in an electrically floating state.
    Type: Application
    Filed: May 16, 2001
    Publication date: April 4, 2002
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Tadao Kadowaki, Masayuki Yamaguchi, Akihiko Ebina, Yoko Sato
  • Publication number: 20010052809
    Abstract: A constant-voltage generation circuit 100 creates a constant voltage.
    Type: Application
    Filed: August 6, 2001
    Publication date: December 20, 2001
    Applicant: Seiko Epson Corporation
    Inventors: Tadao Kadowaki, Yoshiki Makiuchi, Shinji Nakamiya
  • Publication number: 20010043106
    Abstract: A constant-voltage generation circuit 100 creates a constant voltage.
    Type: Application
    Filed: June 29, 2001
    Publication date: November 22, 2001
    Applicant: Seiko Epson Corporation
    Inventors: Tadao Kadowaki, Yoshiki Makiuchi, Shinji Nakamiya
  • Patent number: 6288600
    Abstract: A constant-voltage generation circuit is provided which creates a constant voltage. The constant-voltage generation circuit may consist of a first voltage creation circuit for creating a reference voltage and a second voltage creation circuit for creating a constant voltage which has a predetermined relationship with the reference voltage. The first voltage creation circuit may consist of a constant-current source for supplying a constant current and a voltage-control transistor through which this constant current flows, for outputting the reference voltage on the basis of a predetermined potential. The constant current is set to a value within the saturated operating region of the voltage-control transistor.
    Type: Grant
    Filed: January 15, 1999
    Date of Patent: September 11, 2001
    Assignee: Seiko Epson Corporation
    Inventors: Tadao Kadowaki, Yoshiki Makiuchi, Shinji Nakamiya
  • Patent number: 6166609
    Abstract: A crystal oscillation circuit that is capable of operating stably with a low power consumption includes a signal inversion amplifier and a power control circuit that controls the power voltage of this signal inversion amplifier in accordance with an oscillation output. The power control circuit includes a power voltage generation circuit that outputs a plurality of power voltages of different values; a determination control portion that determines the optimal value of the power voltage to be applied to the signal inversion amplifier, based on the oscillation output; and a multiplexer that controls the switching of the power voltage applied to the signal inversion amplifier from the power voltage generation circuit, based on the result of that determination.
    Type: Grant
    Filed: April 8, 1998
    Date of Patent: December 26, 2000
    Assignee: Seiko Epson Corporation
    Inventors: Shinji Nakamiya, Tadao Kadowaki, Yoshiki Makiuchi
  • Patent number: 6147564
    Abstract: An oscillation circuit including an electrostatic protective circuit connected between a signal path and this constant voltage V.sub.reg. It comprises a first electrostatic protective circuit portion that causes any electrostatic voltage of a first polarity that invades the signal path to be selectively diverted through a diode to the constant voltage V.sub.reg side of the circuit, and any electrostatic voltage of a second polarity that invades the signal path to be selectively diverted through another diode to the ground side. This ensures that the oscillation circuit is not affected by fluctuations in the power voltage from the main power source, enabling it to oscillate at a stable frequency.
    Type: Grant
    Filed: March 4, 1999
    Date of Patent: November 14, 2000
    Assignee: Seiko Epson Corporation
    Inventors: Shinji Nakamiya, Hiroshi Yabe, Tadao Kadowaki, Yoshiki Makiuchi
  • Patent number: 6097257
    Abstract: An oscillation circuit comprising a control circuit that utilizes the body effect of a substrate bias to control the source potential of a MOSFET that configures a signal inversion amplifier. This control circuit controls the threshold voltage of this MOSFET to be low when power is first applied to the oscillation circuit, and controls the threshold voltage of the MOSFET to be high after the oscillation of the oscillation circuit has stabilized. This makes it possible to ensure that the oscillation circuit oscillates stably and at a low power consumption.
    Type: Grant
    Filed: January 7, 1999
    Date of Patent: August 1, 2000
    Assignee: Seiko Epson Corporation
    Inventors: Tadao Kadowaki, Yoshiki Makiuchi, Shinji Nakamiya
  • Patent number: 6046648
    Abstract: A crystal oscillation circuit that oscillates stably with a low power consumption includes an inverting amplifier, a crystal oscillator, and a feedback circuit that inverts the phase of an output from this inverting amplifier and feeds it back as an input. The inverting amplifying includes first and second semiconductor switching elements. The sum of the absolute value of the threshold voltage of the first semiconductor switching element and the absolute value of the threshold voltage of the second semiconductor switching element is set to be greater than or equal to the absolute value of the potential difference between first and second potentials, in order to prevent the first and second semiconductor switching elements from being on simultaneously.
    Type: Grant
    Filed: December 18, 1997
    Date of Patent: April 4, 2000
    Assignee: Seiko Epson Corporation
    Inventors: Shinji Nakamiya, Hiroshi Yabe, Tadao Kadowaki, Yoshiki Makiuchi
  • Patent number: 5929715
    Abstract: An oscillation circuit is driven at reduced power by a constant voltage V.sub.reg having an absolute value that is lower than that of a power voltage V.sub.ss of a main power source. An electrostatic protective circuit provided in this oscillation circuit is connected between a signal path and this constant voltage V.sub.reg. It comprises a first electrostatic protective circuit portion that causes any electrostatic voltage of a first polarity that invades the signal path to be selectively diverted through a diode to the constant voltage V.sub.reg side of the circuit, and any electrostatic voltage of a second polarity that invades the signal path to be selectively diverted through another diode to the ground side. This ensures that the oscillation circuit is not affected by fluctuations in the power voltage from the main power source, enabling it to oscillate at a stable frequency.
    Type: Grant
    Filed: December 3, 1997
    Date of Patent: July 27, 1999
    Inventors: Shinji Nakamiya, Hiroshi Yabe, Tadao Kadowaki, Yoshiki Makiuchi
  • Patent number: RE39329
    Abstract: This invention relates to a crystal oscillation circuit that oscillates stably with a low power consumption. This crystal oscillation circuit comprises an inverting amplifier, a crystal oscillator, and a feedback circuit that inverts the phase of an output from this inverting amplifier and feeds it back as an input. The sum of the absolute value of the threshold voltage of a first semiconductor switching element and the absolute value of the threshold voltage of a second semiconductor switching element is set to be greater than or equal to the absolute value of the potential difference between first and second potentials, when said inverting amplifier includes the first and second semiconductor switching elements.
    Type: Grant
    Filed: February 7, 2003
    Date of Patent: October 10, 2006
    Assignee: Seiko Epson Corporation
    Inventors: Hiroshi Yabe, Shinji Nakamiya, Tadao Kadowaki, Yoshiki Makiuchi