Patents by Inventor Ritsuko Nomura

Ritsuko Nomura 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: 7570034
    Abstract: A step-up/down DC-DC converter is disclosed that includes: a step-up/down part generating an output voltage by stepping up or down an input voltage; and a control part generating an error signal indicating an error between a voltage value obtained by dividing the output voltage and a predetermined reference voltage, and causing the step-up/down part to perform a step-up or step-down operation based on the comparison between the error signal and first and second triangle wave signals. The control part includes a first circuit generating the first triangle wave signal for step-down control and a second circuit generating the second triangle wave signal for step-up control. The first circuit generates a clock signal synchronized with the first triangle wave signal, and outputs the clock signal to the second circuit. The second circuit generates the second triangle wave signal synchronized with the first triangle wave signal based on the input clock signal.
    Type: Grant
    Filed: January 25, 2008
    Date of Patent: August 4, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Shohichi Nitta, Masahiro Matsuo, Ritsuko Nomura
  • Publication number: 20080211474
    Abstract: A step-up/down DC-DC converter is disclosed that includes: a step-up/down part generating an output voltage by stepping up or down an input voltage; and a control part generating an error signal indicating an error between a voltage value obtained by dividing the output voltage and a predetermined reference voltage, and causing the step-up/down part to perform a step-up or step-down operation based on the comparison between the error signal and first and second triangle wave signals. The control part includes a first circuit generating the first triangle wave signal for step-down control and a second circuit generating the second triangle wave signal for step-up control. The first circuit generates a clock signal synchronized with the first triangle wave signal, and outputs the clock signal to the second circuit. The second circuit generates the second triangle wave signal synchronized with the first triangle wave signal based on the input clock signal.
    Type: Application
    Filed: January 25, 2008
    Publication date: September 4, 2008
    Inventors: Shohichi Nitta, Masahiro Matsuo, Ritsuko Nomura
  • Patent number: 7391189
    Abstract: A step-up/down DC-DC converter is disclosed that includes: a step-up/down part generating an output voltage by stepping up or down an input voltage; and a control part generating an error signal indicating an error between a voltage value obtained by dividing the output voltage and a predetermined reference voltage, and causing the step-up/down part to perform a step-up or step-down operation based on the comparison between the error signal and first and second triangle wave signals. The control part includes a first circuit generating the first triangle wave signal for step-down control and a second circuit generating the second triangle wave signal for step-up control. The first circuit generates a clock signal synchronized with the first triangle wave signal, and outputs the clock signal to the second circuit. The second circuit generates the second triangle wave signal synchronized with the first triangle wave signal based on the input clock signal.
    Type: Grant
    Filed: April 22, 2004
    Date of Patent: June 24, 2008
    Assignee: Ricoh Company, Ltd.
    Inventors: Shohichi Nitta, Masahiro Matsuo, Ritsuko Nomura
  • Publication number: 20060208718
    Abstract: A step-up/down DC-DC converter is disclosed that includes: a step-up/down part generating an output voltage by stepping up or down an input voltage; and a control part generating an error signal indicating an error between a voltage value obtained by dividing the output voltage and a predetermined reference voltage, and causing the step-up/down part to perform a step-up or step-down operation based on the comparison between the error signal and first and second triangle wave signals. The control part includes a first circuit generating the first triangle wave signal for step-down control and a second circuit generating the second triangle wave signal for step-up control. The first circuit generates a clock signal synchronized with the first triangle wave signal, and outputs the clock signal to the second circuit. The second circuit generates the second triangle wave signal synchronized with the first triangle wave signal based on the input clock signal.
    Type: Application
    Filed: April 22, 2004
    Publication date: September 21, 2006
    Inventors: Shohichi Nitta, Masahiro Matsuo, Ritsuko Nomura
  • Patent number: 7095216
    Abstract: A power supply apparatus includes a plurality of power source circuits, an oscillator circuit and a controller. The plurality of power source circuits use a common direct current power source. The oscillator circuit generates a plurality of oscillator signals. The controller performs a time sharing control based on the plurality of oscillator signals to enable the plurality of power source circuits to receive power from the common direct current power source in different timings and to output respective voltages.
    Type: Grant
    Filed: September 26, 2003
    Date of Patent: August 22, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahiro Matsuo, Ritsuko Nomura
  • Patent number: 6917190
    Abstract: A power supply apparatus includes an output voltage generator, a reference voltage generator, a voltage divider, and a voltage control circuit. An input voltage is supplied from a direct current power source. The output voltage generator generates a constant output voltage based on the input voltage. The reference voltage generator generates a reference voltage. The voltage divider divides the constant output voltage into a divided voltage in accordance with a voltage dividing ratio variable in response to an externally-input control signal. The voltage control circuit controls the output voltage generator to regulate the constant output voltage such that the divided voltage from the voltage divider is equalized to the reference voltage.
    Type: Grant
    Filed: June 26, 2003
    Date of Patent: July 12, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahiro Matsuo, Shoichi Nitta, Ritsuko Nomura
  • Publication number: 20040113495
    Abstract: A power supply apparatus includes a plurality of power source circuits, an oscillator circuit and a controller. The plurality of power source circuits use a common direct current power source. The oscillator circuit generates a plurality of oscillator signals. The controller performs a time sharing control based on the plurality of oscillator signals to enable the plurality of power source circuits to receive power from the common direct current power source in different timings and to output respective voltages.
    Type: Application
    Filed: September 26, 2003
    Publication date: June 17, 2004
    Inventors: Masahiro Matsuo, Ritsuko Nomura
  • Publication number: 20040051509
    Abstract: A power supply apparatus includes an output voltage generator, a reference voltage generator, a voltage divider, and a voltage control circuit. An input voltage is supplied from a direct current power source. The output voltage generator generates a constant output voltage based on the input voltage. The reference voltage generator generates a reference voltage. The voltage divider divides the constant output voltage into a divided voltage in accordance with a voltage dividing ratio variable in response to an externally-input control signal. The voltage control circuit controls the output voltage generator to regulate the constant output voltage such that the divided voltage from the voltage divider is equalized to the reference voltage.
    Type: Application
    Filed: June 26, 2003
    Publication date: March 18, 2004
    Inventors: Masahiro Matsuo, Shoichi Nitta, Ritsuko Nomura