Patents by Inventor Shigeaki Nakazawa

Shigeaki Nakazawa 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: 9979293
    Abstract: A power source apparatus includes a power input terminal to which input direct-current power is input from a power source; a first switching regulator coupled to the power input terminal and configured to supply, to a first electronic component, first direct-current power obtained by converting a voltage of the input direct-current power into a first voltage; a second switching regulator coupled to the power input terminal and configured to supply, to a second electronic component, second direct-current power obtained by converting the voltage of the input direct-current power into a second voltage; and a signal generating circuit configured to generate, based on a first oscillation voltage of the first switching regulator, a reference signal to be a reference of a timing of switching the second switching regulator such that the first oscillation voltage and a second oscillation voltage of the second switching regulator become opposite in phase.
    Type: Grant
    Filed: February 6, 2017
    Date of Patent: May 22, 2018
    Assignee: FUJITSU LIMITED
    Inventor: Shigeaki Nakazawa
  • Publication number: 20170244322
    Abstract: A power source apparatus includes a power input terminal to which input direct-current power is input from a power source; a first switching regulator coupled to the power input terminal and configured to supply, to a first electronic component, first direct-current power obtained by converting a voltage of the input direct-current power into a first voltage; a second switching regulator coupled to the power input terminal and configured to supply, to a second electronic component, second direct-current power obtained by converting the voltage of the input direct-current power into a second voltage; and a signal generating circuit configured to generate, based on a first oscillation voltage of the first switching regulator, a reference signal to be a reference of a timing of switching the second switching regulator such that the first oscillation voltage and a second oscillation voltage of the second switching regulator become opposite in phase.
    Type: Application
    Filed: February 6, 2017
    Publication date: August 24, 2017
    Applicant: FUJITSU LIMITED
    Inventor: Shigeaki NAKAZAWA
  • Publication number: 20160352108
    Abstract: An electronic apparatus includes: a battery that is charged with power supplied from a power supply adaptor; a load unit that is arranged on a supply path through which power is supplied from the power supply adaptor and the battery; and a power supply control unit that detects a load of the load unit and output a control signal which causes the power supply adaptor to change an output voltage based on the load.
    Type: Application
    Filed: May 27, 2016
    Publication date: December 1, 2016
    Applicant: FUJITSU LIMITED
    Inventor: Shigeaki NAKAZAWA
  • Publication number: 20150067364
    Abstract: A CPU and a miscellaneous system are operated by electrical power supplied from an AC adapter or a battery. An AC adapter identifying circuit includes a voltage determining comparator that determines whether a voltage from the AC adapter is equal to or greater than a voltage threshold; a current determining comparator that determines whether a current supplied from the AC adapter is equal to or greater than a current threshold; and an electrical power saving control circuit that drops, when the supplied voltage is lower than the voltage threshold and the supplied current is equal to or greater than the current threshold, electrical power consumed by the CPU and the miscellaneous system.
    Type: Application
    Filed: July 7, 2014
    Publication date: March 5, 2015
    Inventor: Shigeaki NAKAZAWA
  • Patent number: 8433932
    Abstract: A power circuit, information processing apparatus, and power control method are provided. The power circuit includes a determining unit configured to determine whether a control signal provided to control a power source has a fixed frequency characteristic, and an adjusting unit configured to randomly change time when a voltage transmitted to the power source is changed within a prescribed range when the determining unit determines that the control signal has the fixed frequency characteristic.
    Type: Grant
    Filed: November 13, 2009
    Date of Patent: April 30, 2013
    Assignee: Fujitsu Limited
    Inventor: Shigeaki Nakazawa
  • Patent number: 8076915
    Abstract: To improve conversion efficiency at a DC-DC conversion time by providing driving units respectively for a plurality of switches and controlling the switches corresponding to a load current, an input voltage, an output voltage and an input/output voltage difference. When synchronously rectifying a plurality of first switches and a plurality of second switches by setting the first switches and the second switches alternately in an ON-state, the plurality of first switches are driven repeatedly in the ON- or OFF-state corresponding to a required output, the plurality of second switches are driven in the ON- or OFF-state in synchronization with the first switches, the driving of part of the plurality of first switches and part or all of the plurality of second switches is stopped corresponding to a load current value, an input voltage value, an output voltage value or an input/output voltage difference value.
    Type: Grant
    Filed: January 21, 2009
    Date of Patent: December 13, 2011
    Assignee: Fujitsu Limited
    Inventor: Shigeaki Nakazawa
  • Publication number: 20100153753
    Abstract: A power circuit, information processing apparatus, and power control method are provided. The power circuit includes a determining unit configured to determine whether a control signal provided to control a power source has a fixed frequency characteristic, and an adjusting unit configured to randomly change time when a voltage transmitted to the power source is changed within a prescribed range when the determining unit determines that the control signal has the fixed frequency characteristic.
    Type: Application
    Filed: November 13, 2009
    Publication date: June 17, 2010
    Applicant: FUJITSU LIMITED
    Inventor: Shigeaki NAKAZAWA
  • Publication number: 20090230939
    Abstract: To improve conversion efficiency at a DC-DC conversion time by providing driving units respectively for a plurality of switches and controlling the switches corresponding to a load current, an input voltage, an output voltage and an input/output voltage difference. When synchronously rectifying a plurality of first switches and a plurality of second switches by setting the first switches and the second switches alternately in an ON-state, the plurality of first switches are driven repeatedly in the ON- or OFF-state corresponding to a required output, the plurality of second switches are driven in the ON- or OFF-state in synchronization with the first switches, the driving of part of the plurality of first switches and part or all of the plurality of second switches is stopped corresponding to a load current value, an input voltage value, an output voltage value or an input/output voltage difference value.
    Type: Application
    Filed: January 21, 2009
    Publication date: September 17, 2009
    Applicant: FUJITSU LIMITED
    Inventor: Shigeaki Nakazawa
  • Patent number: 7492135
    Abstract: To improve conversion efficiency at a DC-DC conversion time by providing driving units respectively for a plurality of switches and controlling the switches corresponding to a load current, an input voltage, an output voltage and an input/output voltage difference. When synchronously rectifying a plurality of first switches and a plurality of second switches by setting the first switches and the second switches alternately in an ON-state, the plurality of first switches are driven repeatedly in the ON- or OFF-state corresponding to a required output, the plurality of second switches are driven in the ON- or OFF-state in synchronization with the first switches, the driving of part of the plurality of first switches and part or all of the plurality of second switches is stopped corresponding to a load current value, an input voltage value, an output voltage value or an input/output voltage difference value.
    Type: Grant
    Filed: March 17, 2006
    Date of Patent: February 17, 2009
    Assignee: Fujitsu Limited
    Inventors: Mitsuo Saeki, Kouichi Matsuda, Shigeaki Nakazawa
  • Publication number: 20060208715
    Abstract: To improve conversion efficiency at a DC-DC conversion time by providing driving units respectively for a plurality of switches and controlling the switches corresponding to a load current, an input voltage, an output voltage and an input/output voltage difference. When synchronously rectifying a plurality of first switches and a plurality of second switches by setting the first switches and the second switches alternately in an ON-state, the plurality of first switches are driven repeatedly in the ON- or OFF-state corresponding to a required output, the plurality of second switches are driven in the ON- or OFF-state in synchronization with the first switches, the driving of part of the plurality of first switches and part or all of the plurality of second switches is stopped corresponding to a load current value, an input voltage value, an output voltage value or an input/output voltage difference value.
    Type: Application
    Filed: March 17, 2006
    Publication date: September 21, 2006
    Applicant: FUJITSU LIMITED
    Inventors: Mitsuo Saeki, Kouichi Matsuda, Shigeaki Nakazawa
  • Patent number: 6940737
    Abstract: A power supply control circuit connectable with an input power monitor that monitors an input power value to the power supply, an output power monitor that monitors an output power value from the power supply, and an output power controller that varies the output power value from the power supply, the power supply control circuit having an output power determiner that determines a determined output power value depending on the input power value and a power adjuster that adjusts the output power value to the determined output power value by controlling the output power controller.
    Type: Grant
    Filed: June 19, 2003
    Date of Patent: September 6, 2005
    Assignee: Fujitsu Limited
    Inventors: Shigeaki Nakazawa, Hidetoshi Yano, Hidekiyo Ozawa, Mitsuo Saeki, Kouichi Matsuda, Shigeo Tanaka
  • Patent number: 6909619
    Abstract: There are disclosed a synchronous rectifying type of DC—DC converter, a DC—DC converter control circuit constituting such a type of DC—DC converter, a monitor circuit for monitoring an operation of a DC—DC converter, and an electronic equipment having a DC—DC converter, considering a conduction current. A DC—DC converter has a main switch and a synchronous rectifying switch, in which said main switch and said synchronous rectifying switch are alternately turned on so that a voltage of a DC electric power is transformed and outputted. A state that said main switch and said synchronous rectifying switch are simultaneously turned on is detected.
    Type: Grant
    Filed: January 29, 2001
    Date of Patent: June 21, 2005
    Assignee: Fujitsu Limited
    Inventors: Mitsuo Saeki, Shigeaki Nakazawa, Kouichi Matsuda
  • Publication number: 20040105281
    Abstract: A power supply control circuit connectable with an input power monitor that monitors an input power value to the power supply, an output power monitor that monitors an output power value from the power supply, and an output power controller that varies the output power value from the power supply, the power supply control circuit having an output power determiner that determines a determined output power value depending on the input power value and a power adjuster that adjusts the output power value to the determined output power value by controlling the output power controller.
    Type: Application
    Filed: June 19, 2003
    Publication date: June 3, 2004
    Inventors: Shigeaki Nakazawa, Hidetoshi Yano, Hidekiyo Ozawa, Mitsuo Saeki, Kouichi Matsuda, Shigeo Tanaka
  • Patent number: 6639812
    Abstract: A power supply control circuit connectable with an input power monitor that monitors an input power value to the power supply, an output power monitor that monitors an output power value from the power supply, and an output power controller that varies the output power value from the power supply, the power supply control circuit having an output power determiner that determines a determined output power value depending on the input power value and a power adjuster that adjusts the output power value to the determined output power value by controlling the output power controller.
    Type: Grant
    Filed: September 6, 2001
    Date of Patent: October 28, 2003
    Assignee: Fujitsu Limited
    Inventors: Shigeaki Nakazawa, Hidetoshi Yano, Hidekiyo Ozawa, Mitsuo Saeki, Kouichi Matsuda, Shigeo Tanaka
  • Patent number: 6366475
    Abstract: A power control circuit for controlling an output of a power supply is provided with a setting section which variably sets a maximum rated output based on input temperature information.
    Type: Grant
    Filed: March 27, 2000
    Date of Patent: April 2, 2002
    Assignee: Fujitsu Limited
    Inventors: Shigeaki Nakazawa, Hidetoshi Yano, Shigeo Tanaka, Hidekiyo Ozawa
  • Publication number: 20020027786
    Abstract: A power supply control circuit connectable with an input power monitor that monitors an input power value to the power supply, an output power monitor that monitors an output power value from the power supply, and an output power controller that varies the output power value from the power supply, the power supply control circuit having an output power determiner that determines a determined output power value depending on the input power value and a power adjuster that adjusts the output power value to the determined output power value by controlling the output power controller.
    Type: Application
    Filed: September 6, 2001
    Publication date: March 7, 2002
    Applicant: Fujitsu Limited
    Inventors: Shigeaki Nakazawa, Hidetoshi Yano, Hidekiyo Ozawa, Mitsuo Saeki, Kouichi Matsuda, Shigeo Tanaka
  • Publication number: 20020015316
    Abstract: A power control circuit for controlling an output of a power supply is provided with a setting section which variably sets a maximum rated output based on input temperature information.
    Type: Application
    Filed: March 27, 2000
    Publication date: February 7, 2002
    Inventors: Shigeaki Nakazawa, Hidetoshi Yano, Shigeo Tanaka, Hidekiyo Ozawa
  • Publication number: 20020001206
    Abstract: There are disclosed a synchronous rectifying type of DC-DC converter, a DC-DC converter control circuit constituting such a type of DC-DC converter, a monitor circuit for monitoring an operation of a DC-DC converter, and an electronic equipment having a DC-DC converter, considering a conduction current. A DC-DC converter has a main switch and a synchronous rectifying switch, in which said main switch and said synchronous rectifying switch are alternately turned on so that a voltage of a DC electric power is transformed and outputted. A state that said main switch and said synchronous rectifying switch are simultaneously turned on is detected.
    Type: Application
    Filed: January 29, 2001
    Publication date: January 3, 2002
    Inventors: Mitsuo Saeki, Shigeaki Nakazawa, Kouichi Matsuda