Patents by Inventor Kei Nagatomo

Kei Nagatomo 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: 8228131
    Abstract: In a crystal-oscillator circuit having a quartz crystal unit, further stabilization of output frequency change at a time of startup of the power supply is achieved. A crystal-oscillator circuit having a quartz crystal unit includes a first variable-capacitance element, which forms an oscillation loop with the quartz crystal unit, and a temperature compensation circuit which provides a first control signal for the first variable-capacitance element to compensate for a temperature characteristic of the quartz crystal unit. In addition, the crystal-oscillator circuit includes a second variable-capacitance element group, and a time constant circuit which provides a time constant signal, which changes with a predetermined time constant, for the second variable-capacitance element group as a second control signal.
    Type: Grant
    Filed: January 12, 2011
    Date of Patent: July 24, 2012
    Assignee: Panasonic Corporation
    Inventors: Kei Nagatomo, Hisato Takeuchi, Shuuji Shibuya
  • Publication number: 20110227655
    Abstract: In a crystal-oscillator circuit having a quartz crystal unit, further stabilization of output frequency change at a time of startup of the power supply is achieved. A crystal-oscillator circuit having a quartz crystal unit includes a first variable-capacitance element, which forms an oscillation loop with the quartz crystal unit, and a temperature compensation circuit which provides a first control signal for the first variable-capacitance element to compensate for a temperature characteristic of the quartz crystal unit. In addition, the crystal-oscillator circuit includes a second variable-capacitance element group, and a time constant circuit which provides a time constant signal, which changes with a predetermined time constant, for the second variable-capacitance element group as a second control signal.
    Type: Application
    Filed: January 12, 2011
    Publication date: September 22, 2011
    Inventors: Kei NAGATOMO, Hisato Takeuchi, Shuuji Shibuya
  • Patent number: 7808333
    Abstract: A temperature-compensated crystal oscillator includes a mode selector circuit 100, a control logic serial•interface 200, a PROM circuit 300, an oscillation control circuit 400 and an oscillation circuit 500, and has, as terminals, a power terminal (VCC/CLK) 11, an input terminal (VC/DATA/PE) 12, an output terminal (OUT) 13 and a ground terminal (GND) 14. The mode selector circuit 100 switches the crystal oscillator to an emulation mode when a first signal in which a power voltage and a clock signal supplied through the power terminal 11 are superimposed, is inputted from the power terminal and a second signal having a predetermined pattern is inputted from the input terminal 12.
    Type: Grant
    Filed: April 18, 2008
    Date of Patent: October 5, 2010
    Assignee: Panasonic Corporation
    Inventors: Hisato Takeuchi, Keigo Shingu, Kei Nagatomo
  • Patent number: 7633350
    Abstract: A first order function generation circuit receives a signal from a temperature sensor circuit, and generates a first order function control signal V1 that is affected by the ambient temperature. A fourth order and fifth order approximation function generation circuit receives signals from the temperature sensor circuit and from the third order approximation function generation circuit, and generates a fourth and fifth order approximation function control signal V45 that is affected by the ambient temperature. A peak change point adjustment circuit outputs a signal to adjust the value of a peak change point temperature Ti for the third order approximation function generation circuit, the first order generation function circuit and the fourth order and fifth order approximation function generation circuit. A temperature compensation circuit adds together control signals V0, V1, V3 and V5, and outputs the resultant signal Vc.
    Type: Grant
    Filed: May 31, 2007
    Date of Patent: December 15, 2009
    Assignee: Panasonic Corporation
    Inventors: Kei Nagatomo, Hisato Takeuchi, Keigo Shingu
  • Patent number: 7579917
    Abstract: The object of the present invention is to provide a crystal oscillator with one IC capable of effectively responding to specifications or a frequency of an installed set, an output terminal of the oscillator 1 is connected to an input terminal of the inverter 2, an output terminal of which is connected to the first resistor 7 and one terminal of the second resistor 8, the other terminal of the first resistor 7 is connected to one terminal of the first capacitor 9 and an input terminal of the first transistor 3, the other terminal of the first capacitor 9 is connected to one terminal of the first switch 11, and the other terminal of the first switch 11 is grounded, the other terminal of the second resistor 8 is connected to one terminal of the second capacitor 10 and an input terminal of the second transistor 4, the other terminal of the second capacitor 10 is connected to one terminal of the second switch 12, and the other terminal of the second switch 12 is grounded, an output terminal of the first transisto
    Type: Grant
    Filed: March 23, 2007
    Date of Patent: August 25, 2009
    Assignee: Panasonic Corporation
    Inventors: Motoki Sakai, Hisato Takeuchi, Keigo Shingu, Kei Nagatomo
  • Patent number: 7492231
    Abstract: An oscillator starting control circuit capable of shortening a starting time and stably controlling the starting time, and furthermore, stabilizing an oscillating frequency after starting an oscillating circuit. An oscillating circuit (1) is a crystal oscillating circuit in which an input and an output of an inverter (14) are connected to both ends of a crystal oscillator (15) and both ends of a resistor (16), the input is connected to a drain of an MOS variable capacity (10), the output is connected to a drain of an MOS variable capacity (11), a source of the MOS variable capacity (10) is connected to a fixed capacity (12), a source of the MOS variable capacity (11) is connected to a fixed capacity (13), and the other ends of the fixed capacities (12, 13) are connected to a GND.
    Type: Grant
    Filed: September 29, 2005
    Date of Patent: February 17, 2009
    Assignee: Panasonic Corporation
    Inventors: Kei Nagatomo, Keigo Shingu, Hisato Takeuchi
  • Publication number: 20080258830
    Abstract: A temperature-compensated crystal oscillator includes a mode selector circuit 100, a control logic serial•interface 200, a PROM circuit 300, an oscillation control circuit 400 and an oscillation circuit 500, and has, as terminals, a power terminal (VCC/CLK) 11, an input terminal (VC/DATA/PE) 12, an output terminal (OUT) 13 and a ground terminal (GND) 14. The mode selector circuit 100 switches the crystal oscillator to an emulation mode when a first signal in which a power voltage and a clock signal supplied through the power terminal 11 are superimposed, is inputted from the power terminal and a second signal having a predetermined pattern is inputted from the input terminal 12.
    Type: Application
    Filed: April 18, 2008
    Publication date: October 23, 2008
    Inventors: Hisato Takeuchi, Keigo Shingu, Kei Nagatomo
  • Publication number: 20080007363
    Abstract: A first order function generation circuit receives a signal from a temperature sensor circuit, and generates a fist order function control signal V1 that is affected by the ambient temperature. A fourth order and fifth order approximation function generation circuit receives signals from the temperature sensor circuit and from the third order approximation function generation circuit, and generates a fourth and fifth order approximation function control signal V45 that is affected by the ambient temperature. A peak change point adjustment circuit outputs a signal to adjust the value of a peak change point temperature Ti for the third order approximation function generation circuit, the first order generation function circuit and the fourth order and fifth order approximation function generation circuit. A temperature compensation circuit adds together control signals V0, V1, V3 and V5, and outputs the resultant signal Vc.
    Type: Application
    Filed: May 31, 2007
    Publication date: January 10, 2008
    Inventors: Kei Nagatomo, Hisato Takeuchi, Keigo Shingu
  • Publication number: 20070236302
    Abstract: The object of the present invention is to provide a crystal oscillator with one IC capable of effectively responding to specifications or a frequency of an installed set, an output terminal of the oscillator 1 is connected to an input terminal of the inverter 2, an output terminal of which is connected to the first resistor 7 and one terminal of the second resistor 8, the other terminal of the first resistor 7 is connected to one terminal of the first capacitor 9 and an input terminal of the first transistor 3, the other terminal of the first capacitor 9 is connected to one terminal of the first switch 11, and the other terminal of the first switch 11 is grounded, the other terminal of the second resistor 8 is connected to one terminal of the second capacitor 10 and an input terminal of the second transistor 4, the other terminal of the second capacitor 10 is connected to one terminal of the second switch 12, and the other terminal of the second switch 12 is grounded, an output terminal of the first transisto
    Type: Application
    Filed: March 23, 2007
    Publication date: October 11, 2007
    Inventors: Motoki Sakai, Hisato Takeuchi, Keigo Shingu, Kei Nagatomo
  • Publication number: 20070222532
    Abstract: There is provided a temperature-compensated crystal oscillator for reducing a voltage noise of a cubic function control voltage controlling an output frequency of an oscillation circuit. A temperature-compensated crystal oscillator includes a quartz vibrator, an amplifier having an oscillation frequency controller, and a temperature compensation circuit of a crystal oscillation frequency, wherein a reference voltage for a compensation voltage of the temperature compensation circuit is generated using a forward voltage of a diode.
    Type: Application
    Filed: March 7, 2007
    Publication date: September 27, 2007
    Inventors: Hisato Takeuchi, Keigo Shingu, Kei Nagatomo
  • Publication number: 20060071730
    Abstract: It is an object to provide an oscillator starting control circuit capable of shortening a starting time and stably controlling the starting time, and furthermore, stabilizing an oscillating frequency after starting an oscillating circuit. [Means for Resolution] An oscillating circuit (1) is a crystal oscillating circuit in which an input and an output of an inverter (14) are connected to both ends of a crystal oscillator (15) and both ends of a resistor (16), the input is connected to a drain of an MOS variable capacity (10), the output is connected to a drain of an MOS variable capacity (11), a source of the MOS variable capacity (10) is connected to a fixed capacity (12), a source of the MOS variable capacity (11) is connected to a fixed capacity (13), and the other ends of the fixed capacities (12, 13) are connected to a GND.
    Type: Application
    Filed: September 29, 2005
    Publication date: April 6, 2006
    Inventors: Kei Nagatomo, Keigo Shingu, Hisato Takeuchi