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).
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Patent number: 9979293Abstract: 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: GrantFiled: February 6, 2017Date of Patent: May 22, 2018Assignee: FUJITSU LIMITEDInventor: Shigeaki Nakazawa
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Publication number: 20170244322Abstract: 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: ApplicationFiled: February 6, 2017Publication date: August 24, 2017Applicant: FUJITSU LIMITEDInventor: Shigeaki NAKAZAWA
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Publication number: 20160352108Abstract: 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: ApplicationFiled: May 27, 2016Publication date: December 1, 2016Applicant: FUJITSU LIMITEDInventor: Shigeaki NAKAZAWA
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Publication number: 20150067364Abstract: 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: ApplicationFiled: July 7, 2014Publication date: March 5, 2015Inventor: Shigeaki NAKAZAWA
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Patent number: 8433932Abstract: 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: GrantFiled: November 13, 2009Date of Patent: April 30, 2013Assignee: Fujitsu LimitedInventor: Shigeaki Nakazawa
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Patent number: 8076915Abstract: 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: GrantFiled: January 21, 2009Date of Patent: December 13, 2011Assignee: Fujitsu LimitedInventor: Shigeaki Nakazawa
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Publication number: 20100153753Abstract: 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: ApplicationFiled: November 13, 2009Publication date: June 17, 2010Applicant: FUJITSU LIMITEDInventor: Shigeaki NAKAZAWA
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Publication number: 20090230939Abstract: 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: ApplicationFiled: January 21, 2009Publication date: September 17, 2009Applicant: FUJITSU LIMITEDInventor: Shigeaki Nakazawa
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Patent number: 7492135Abstract: 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: GrantFiled: March 17, 2006Date of Patent: February 17, 2009Assignee: Fujitsu LimitedInventors: Mitsuo Saeki, Kouichi Matsuda, Shigeaki Nakazawa
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Publication number: 20060208715Abstract: 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: ApplicationFiled: March 17, 2006Publication date: September 21, 2006Applicant: FUJITSU LIMITEDInventors: Mitsuo Saeki, Kouichi Matsuda, Shigeaki Nakazawa
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Patent number: 6940737Abstract: 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: GrantFiled: June 19, 2003Date of Patent: September 6, 2005Assignee: Fujitsu LimitedInventors: Shigeaki Nakazawa, Hidetoshi Yano, Hidekiyo Ozawa, Mitsuo Saeki, Kouichi Matsuda, Shigeo Tanaka
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Patent number: 6909619Abstract: 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: GrantFiled: January 29, 2001Date of Patent: June 21, 2005Assignee: Fujitsu LimitedInventors: Mitsuo Saeki, Shigeaki Nakazawa, Kouichi Matsuda
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Publication number: 20040105281Abstract: 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: ApplicationFiled: June 19, 2003Publication date: June 3, 2004Inventors: Shigeaki Nakazawa, Hidetoshi Yano, Hidekiyo Ozawa, Mitsuo Saeki, Kouichi Matsuda, Shigeo Tanaka
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Patent number: 6639812Abstract: 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: GrantFiled: September 6, 2001Date of Patent: October 28, 2003Assignee: Fujitsu LimitedInventors: Shigeaki Nakazawa, Hidetoshi Yano, Hidekiyo Ozawa, Mitsuo Saeki, Kouichi Matsuda, Shigeo Tanaka
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Patent number: 6366475Abstract: 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: GrantFiled: March 27, 2000Date of Patent: April 2, 2002Assignee: Fujitsu LimitedInventors: Shigeaki Nakazawa, Hidetoshi Yano, Shigeo Tanaka, Hidekiyo Ozawa
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Publication number: 20020027786Abstract: 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: ApplicationFiled: September 6, 2001Publication date: March 7, 2002Applicant: Fujitsu LimitedInventors: Shigeaki Nakazawa, Hidetoshi Yano, Hidekiyo Ozawa, Mitsuo Saeki, Kouichi Matsuda, Shigeo Tanaka
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Publication number: 20020015316Abstract: 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: ApplicationFiled: March 27, 2000Publication date: February 7, 2002Inventors: Shigeaki Nakazawa, Hidetoshi Yano, Shigeo Tanaka, Hidekiyo Ozawa
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Publication number: 20020001206Abstract: 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: ApplicationFiled: January 29, 2001Publication date: January 3, 2002Inventors: Mitsuo Saeki, Shigeaki Nakazawa, Kouichi Matsuda