Patents by Inventor Mitsuo Saeki
Mitsuo Saeki 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: 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: 20040135559Abstract: A direct-current to direct-current conversion (DC/DC) apparatus includes a control circuit having an error amplifier for voltage control and controlling a direct-current to direct-current conversion based on a pulse width modulation control using an output of the error amplifier. The error amplifier inputs a voltage signal corresponding to an output voltage of a DC/DC result and a plurality of reference voltage signals. The DC/DC apparatus also includes a soft start capacitor to provide one of the plurality of reference voltage signals. The error amplifier amplifies a difference between the voltage signal corresponding to the output voltage of a DC/DC result and a voltage signal of a lower potential among the plurality of reference voltage signals and, based on the amplified output, carries out the pulse width modulation control.Type: ApplicationFiled: December 15, 2003Publication date: July 15, 2004Applicant: FUJITSU LIMITEDInventors: Mitsuo Saeki, Hidetoshi Yano, Hidekiyo Ozawa, Seiya Kitagawa, Toshiyuki Matsuyama, Takashi Matsmoto, Kyuichi Takimoto, Yoshiaki Sano
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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: 6664772Abstract: A direct-current to direct-current conversion (DC/DC) apparatus includes a control circuit having an error amplifier for voltage control and controlling a direct-current to direct-current conversion based on a pulse width modulation control using an output of the error amplifier. The error amplifier inputs a voltage signal corresponding to an output voltage of a DC/DC result and a plurality of reference voltage signals. The DC/DC apparatus also includes a soft start capacitor to provide one of the plurality of reference voltage signals. The error amplifier amplifies a difference between the voltage signal corresponding to the output voltage of a DC/DC result and a voltage signal of a lower potential among the plurality of reference voltage signals and, based on-the amplified output, carries out the pulse width modulation control.Type: GrantFiled: May 21, 2001Date of Patent: December 16, 2003Assignee: Fujitsu LimitedInventors: Mitsuo Saeki, Hidetoshi Yano, Hidekiyo Ozawa, Seiya Kitagawa, Toshiyuki Matsuyama, Takashi Matsumoto, Kyuichi Takimoto, Yoshiaki Sano
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Patent number: 6657415Abstract: When starting charging of an internal battery as a result of connection of an external power source by an AC adapter, a charging control unit sets a first charging voltage at which the charging capacity of the internal battery is maximized. When starting the charging from recognition of reduced capacity of the internal battery due to its self-discharge in desk-top use where the AC adapter is in connection at all times, the charging control unit sets a second charging voltage lower than the first charging voltage to prevent the battery from degrading.Type: GrantFiled: August 16, 2001Date of Patent: December 2, 2003Assignee: Fujitsu LimitedInventors: Mitsuo Saeki, Kouichi Matsuda, Hidekiyo Ozawa, 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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Publication number: 20030168916Abstract: In a DC-DC converter circuit having a plurality of input terminals connected to a plurality of DC power supplies, and an output terminal, the DC-DC converter circuit includes a power supply selection section for selecting a DC power supply of lowest voltage on the condition that the voltage is not less than a predetermined voltage, and a step-down type of regulator section for converting the voltage of the DC power supply selected by the power supply selection section into a predetermined voltage lower than the voltage of the DC power supply selected by the power supply selection section, and outputting the converted voltage through the output terminal.Type: ApplicationFiled: March 12, 2003Publication date: September 11, 2003Applicant: Fujitsu LimitedInventors: Kouichi Matsuda, Mitsuo Saeki, Hidekiyo Ozawa
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Publication number: 20030107355Abstract: A direct-current to direct-current conversion (DC/DC) apparatus includes a control circuit having an error amplifier for voltage control and controlling a direct-current to direct-current conversion based on a pulse width modulation control using an output of the error amplifier. The error amplifier inputs a voltage signal corresponding to an output voltage of a DC/DC result and a plurality of reference voltage signals. The DC/DC apparatus also includes a soft start capacitor to provide one of the plurality of reference voltage signals. The error amplifier amplifies a difference between the voltage signal corresponding to the output voltage of a DC/DC result and a voltage signal of a lower potential among the plurality of reference voltage signals and, based on the amplified output, carries out the pulse width modulation control.Type: ApplicationFiled: May 21, 2001Publication date: June 12, 2003Applicant: Fujitsu LimitedFujitsu LimitedInventors: Mitsuo Saeki, Hidetoshi Yano, Hidekiyo Ozawa, Seiya Kitagawa, Toshiyuki Matsuyama, Takashi Matsumoto, Kyuichi Takimoto, Yoshiaki Sano
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Patent number: 6566766Abstract: In a DC—DC converter circuit having a plurality of input terminals connected to a plurality of DC power supplies, and an output terminal, the DC—DC converter circuit includes a power supply selection section for selecting a DC power supply of lowest voltage on the condition that the voltage is not less than a predetermined voltage, and a step-down type of regulator section for converting the voltage of the DC power supply selected by the power supply selection section into a predetermined voltage lower than the voltage of the DC power supply selected by the power supply selection section, and outputting the converted voltage through the output terminal.Type: GrantFiled: March 15, 2002Date of Patent: May 20, 2003Assignee: Fujitsu LimitedInventors: Kouichi Matsuda, Mitsuo Saeki, Hidekiyo Ozawa
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Publication number: 20030030413Abstract: A protection method for preventing battery cells from over-discharging and being overcharged, a control circuit, and a battery unit are provided. In the protection method, when a set signal “1” is supplied to a set terminal, a flip-flop outputs “1”. The gate of a discharge control FET then becomes “1”, so that the discharge control FET is OFF regardless of a discharge control signal supplied from a voltage monitor circuit. When a reset signal “1” is supplied to a reset terminal, the flip-flop outputs “0”. The discharge control FET is then switched on and off in accordance with the output of a discharge control circuit of the voltage monitor circuit. In this manner, battery cells connected to an electronic device do not over-discharge, even when they are left unused for a long period of time. Thus, the battery unit can be prevented from deteriorating and shortening the life thereof.Type: ApplicationFiled: July 29, 2002Publication date: February 13, 2003Applicant: FUJITSU LIMITEDInventors: Mitsuo Saeki, Masafumi Okumura, Shigeo Tanaka, Hidekiyo Ozawa
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Publication number: 20020190694Abstract: A protection method for preventing battery cells from over-discharging and being overcharged, a control circuit, and a battery unit are provided. In the protection method, when a set signal “1” is supplied to a set terminal, a flip-flop outputs “1”. The gate of a discharge control FET then becomes “1”, so that the discharge control FET is OFF regardless of a discharge control signal supplied from a voltage monitor circuit. When a reset signal “1” is supplied to a reset terminal, the flip-flop outputs “0”. The discharge control FET is then switched on and off in accordance with the output of a discharge control circuit of the voltage monitor circuit. In this manner, battery cells connected to an electronic device do not over-discharge, even when they are left unused for a long period of time. Thus, the battery unit can be prevented from deteriorating and shortening the life thereof.Type: ApplicationFiled: July 29, 2002Publication date: December 19, 2002Applicant: FUJITSU LIMITEDInventors: Mitsuo Saeki, Hidekiyo Ozawa
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Patent number: 6492791Abstract: A protection method for preventing battery cells from over-discharging and being overcharged, a control circuit, and a battery unit are provided. In the protection method, when a set signal “1” is supplied to a set terminal, a flip-flop outputs “1”. The gate of a discharge control FET then becomes “1”, so that the discharge control FET is OFF regardless of a discharge control signal supplied from a voltage monitor circuit. When a reset signal “1” is supplied to a reset terminal, the flip-flop outputs +0”. The discharge control FET is then switched on and off in accordance with the output of a discharge control circuit of the voltage monitor circuit. In this manner, battery cells connected to an electronic device do not over-discharge, even when they are left unused for a long period of time. Thus, the battery unit can be prevented from deteriorating and shortening the life thereof.Type: GrantFiled: March 17, 2000Date of Patent: December 10, 2002Assignee: Fujitsu LimitedInventors: Mitsuo Saeki, Masafumi Okumura, Shigeo Tanaka, Hidekiyo Ozawa
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Patent number: 6486635Abstract: Individual voltages of la plurality of batteries or voltage sources which are connected in series and voltages on both ends of the plurality of batteries or voltage sources are detected. An offset value of a differential amplifier is determined through an arithmetic operation for the detected voltages. The offset value thus determined is used to correct the measured values of the battery voltages.Type: GrantFiled: November 13, 2000Date of Patent: November 26, 2002Assignee: Fujitsu LimitedInventors: Kouichi Matsuda, Nakazawa Shigeaki, Mitsuo Saeki, Hidekiyo Ozawa
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Patent number: 6452364Abstract: A battery charge control circuit, a battery charging device, and a battery charge control method for controlling the charging of a battery are provided. A power source supplies a current to a load, and a battery also supplies a current to the load. If the current supply capacity of the power source is restricted when the power source charges the battery, the charging of the battery is not stopped. Thus, a wrong operation can be avoided, and more reliable battery charging can be performed.Type: GrantFiled: March 22, 2000Date of Patent: September 17, 2002Assignee: Fujitsu LimitedInventors: Mitsuo Saeki, Seiya Kitagawa, Hidekiyo Ozawa, Toshiyuki Matsuyama
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Publication number: 20020097022Abstract: When starting charging of an internal battery as a result of connection of an external power source by an AC adapter, a charging control unit sets a first charging voltage at which the charging capacity of the internal battery is maximized. When starting the charging from recognition of reduced capacity of the internal battery due to its self-discharge in desk-top use where the AC adapter is in connection at all times, the charging control unit sets a second charging voltage lower than the first charging voltage to prevent the battery from degrading.Type: ApplicationFiled: August 16, 2001Publication date: July 25, 2002Applicant: Fujitsu LimitedInventors: Mitsuo Saeki, Kouichi Matsuda, Hidekiyo Ozawa, Shigeo Tanaka
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Publication number: 20020093317Abstract: In a DC-DC converter circuit having a plurality of input terminals connected to a plurality of DC power supplies, and an output terminal, the DC-DC converter circuit includes a power supply selection section for selecting a DC power supply of lowest voltage on the condition that the voltage is not less than a predetermined voltage, and a step-down type of regulator section for converting the voltage of the DC power supply selected by the power supply selection section into a predetermined voltage lower than the voltage of the DC power supply selected by the power supply selection section, and outputting the converted voltage through the output terminal.Type: ApplicationFiled: March 15, 2002Publication date: July 18, 2002Applicant: Fujitsu LimitedInventors: Kouichi Matsuda, Mitsuo Saeki, Hidekiyo Ozawa
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Patent number: 6414403Abstract: A power unit having a built-in battery to supply voltage from the battery over a long period of time by utilizing fully the capabilities of the built-in battery. The power unit supplies electric power to a load even when a battery with a higher battery voltage than the external power source voltage is used by charging the battery from an external power source even when the external power source voltage is lower than the battery voltage. By charging the battery when electric power is supplied to a load from an external power source, the power unit supplies electric power to the load from the battery when the supply of electricity from an external power source is cut off. The power unit includes a having converter to boost output voltage from the battery and to supply the voltage to the load when the battery is discharged and the external power source voltage is higher than the battery voltage.Type: GrantFiled: September 23, 1998Date of Patent: July 2, 2002Assignee: Fujitsu LimitedInventors: Seiya Kitagawa, Mitsuo Saeki, Hidekiyo Ozawa
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Patent number: 6404076Abstract: In a DC-DC converter circuit having a plurality of input terminals connected to a plurality of DC power supplies, and an output terminal, the DC-DC converter circuit includes a power supply selection section for selecting a DC power supply of lowest voltage on the condition that the voltage is not less than a predetermined voltage, and a step-down type of regulator section for converting the voltage of the DC power supply selected by the power supply selection section into a predetermined voltage lower than the voltage of the DC power supply selected by the power supply selection section, and outputting the converted voltage through the output terminal.Type: GrantFiled: October 17, 2000Date of Patent: June 11, 2002Assignee: Fujitsu LimitedInventors: Kouichi Matsuda, Mitsuo Saeki, 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: 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