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: 9065333Abstract: A DC-DC converter includes: an inductor provided between a power input node and a power output node; a plurality of switching elements which switch an input route of a power toward the inductor and a discharge route of the power from the inductor; a first pulse generation circuit which generates a first pulse based on a feed-back signal according to an output of the output node; a second pulse generation circuit which generates a second pulse having a second frequency being equal to or higher than a first frequency set as an upper limit of a human audible frequency band; a driver which drives the switching element based on one of the first pulse and the second pulse; and a control circuit which supplies the first pulse or the second pulse to the driver based on a load state of a load coupled to the output node.Type: GrantFiled: June 11, 2012Date of Patent: June 23, 2015Assignee: FUJITSU LIMITEDInventor: Mitsuo Saeki
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Patent number: 8405357Abstract: A battery unit includes: a battery having cell units connected in parallel, in which one or a plurality of battery cells is connected in series; an external terminal provided for the battery; a switching element provided between each internal terminal and the external terminal of the cell unit; a protection circuit monitoring whether or not a fault occurs in each of the plurality of cell units and cutting off, through the switching element, a connection between the internal terminal and the external terminal of the cell unit with the fault detected; and an informing signal output terminal notifying an external device that the connection with the external terminal with respect to at least one of the cell units is cut off.Type: GrantFiled: July 28, 2009Date of Patent: March 26, 2013Assignee: Fujitsu LimitedInventors: Mitsuo Saeki, Kouichi Matsuda, Akira Takeuchi, Hidetoshi Yano
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Publication number: 20130049716Abstract: A DC-DC converter includes: an inductor provided between a power input node and a power output node; a plurality of switching elements which switch an input route of a power toward the inductor and a discharge route of the power from the inductor; a first pulse generation circuit which generates a first pulse based on a feed-back signal according to an output of the output node; a second pulse generation circuit which generates a second pulse having a second frequency being equal to or higher than a first frequency set as an upper limit of a human audible frequency band; a driver which drives the switching element based on one of the first pulse and the second pulse; and a control circuit which supplies the first pulse or the second pulse to the driver based on a load state of a load coupled to the output node.Type: ApplicationFiled: June 11, 2012Publication date: February 28, 2013Applicant: FUJITSU LIMITEDInventor: Mitsuo SAEKI
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Patent number: 8344718Abstract: A DC-DC converter includes a switching element to generate a pulse waveform by repeatedly admitting and cutting off the input voltage, a fluctuation component restraining circuit to restrain a fluctuation component generated in superposition on the pulse waveform and having a shorter cycle than a cycle of the pulse waveform, and a control circuit to operate the fluctuation component restraining circuit when the input voltage is equal to or larger than a reference voltage.Type: GrantFiled: July 7, 2011Date of Patent: January 1, 2013Assignee: Fujitsu LimitedInventors: Mitsuo Saeki, Koichi Matsuda, Akira Takeuchi
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Publication number: 20110260705Abstract: A DC-DC converter includes a switching element to generate a pulse waveform by repeatedly admitting and cutting off the input voltage, a fluctuation component restraining circuit to restrain a fluctuation component generated in superposition on the pulse waveform and having a shorter cycle than a cycle of the pulse waveform, and a control circuit to operate the fluctuation component restraining circuit when the input voltage is equal to or larger than a reference voltage.Type: ApplicationFiled: July 7, 2011Publication date: October 27, 2011Applicant: FUJITSU LIMITEDInventors: Mitsuo SAEKI, Koichi MATSUDA, Akira TAKEUCHI
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Patent number: 8013587Abstract: A power supply circuit includes: an input terminal; a DC voltage converter that converts a DC input voltage supplied to the input terminal into a DC output voltage; an output terminal that outputs the DC output voltage; a bypass circuit provided to the DC voltage converter between the input terminal and the output terminal; and a monitor control unit that monitors whether or not the DC input voltage satisfies a predetermined condition to be processed in the DC voltage converter, so as to connect the input terminal to the output terminal via the bypass circuit if the DC input voltage does not satisfy the predetermined condition.Type: GrantFiled: August 11, 2008Date of Patent: September 6, 2011Assignee: Fujitsu LimitedInventors: Mitsuo Saeki, Kouichi Matsuda
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Publication number: 20100085014Abstract: A battery unit includes: a battery having cell units connected in parallel, in which one or a plurality of battery cells is connected in series; an external terminal provided for the battery; a switching element provided between each internal terminal and the external terminal of the cell unit; a protection circuit monitoring whether or not a fault occurs in each of the plurality of cell units and cutting off, through the switching element, a connection between the internal terminal and the external terminal of the cell unit with the fault detected; and an informing signal output terminal notifying an external device that the connection with the external terminal with respect to at least one of the cell units is cut off.Type: ApplicationFiled: July 28, 2009Publication date: April 8, 2010Applicant: FUJITSU LIMITEDInventors: Mitsuo SAEKI, Kouichi Matsuda, Akira Takeuchi, Hidetoshi Yano
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Publication number: 20090134861Abstract: A power supply circuit includes: an input terminal; a DC voltage converter that converts a DC input voltage supplied to the input terminal into a DC output voltage; an output terminal that outputs the DC output voltage; a bypass circuit provided to the DC voltage converter between the input terminal and the output terminal; and a monitor control unit that monitors whether or not the DC input voltage satisfies a predetermined condition to be processed in the DC voltage converter, so as to connect the input terminal to the output terminal via the bypass circuit if the DC input voltage does not satisfy the predetermined condition.Type: ApplicationFiled: August 11, 2008Publication date: May 28, 2009Applicant: FUJITSU LIMITEDInventors: Mitsuo SAEKI, Kouichi Matsuda
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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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Patent number: 7148587Abstract: 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 12, 2003Date of Patent: December 12, 2006Assignee: Fujitsu LimitedInventors: Kouichi Matsuda, Mitsuo Saeki, Hidekiyo Ozawa
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Patent number: 7129682Abstract: A direct-current to direct-current conversion (DC/DC) apparatus includes a control circuit having an error amplifier for voltage control, basing the conversion 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 of the output voltage of a DC/DC result and a voltage signal of a lower potential among the plurality of reference voltage signals and carries out the pulse width modulation control. Furthermore, the control circuit includes a circuit for discharging charges corresponding to the output voltage of the DC/DC result when a power supply to the control circuit is turned off.Type: GrantFiled: May 23, 2005Date of Patent: October 31, 2006Assignee: Fujitsu LimitedInventors: Mitsuo Saeki, Hidetoshi Yano, Hidekiyo Ozawa, Seiya Kitagawa, Toshiyuki Matsuyama, Takashi Matsumoto, Kyuichi Takimoto, Yoshiaki Sano
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Publication number: 20060208714Abstract: 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, an output voltage, an input voltage or an input/output voltage difference.Type: ApplicationFiled: September 30, 2005Publication date: September 21, 2006Applicant: Fujitsu LimitedInventors: Mitsuo Saeki, Kouichi Matsuda
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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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Publication number: 20060049804Abstract: 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: October 28, 2005Publication date: March 9, 2006Inventors: Mitsuo Saeki, Hidekiyo Ozawa
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Patent number: 6989652Abstract: 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: July 29, 2002Date of Patent: January 24, 2006Assignee: Fujitsu LimitedInventors: Mitsuo Saeki, Hidekiyo Ozawa
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Publication number: 20050264270Abstract: A direct-current to direct-current conversion (DC/DC) apparatus includes a control circuit having an error amplifier for voltage control, basing the conversion 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 of the output voltage of a DC/DC result and a voltage signal of a lower potential among the plurality of reference voltage signals and carries out the pulse width modulation control. Furthermore, the control circuit includes a circuit for discharging charges corresponding to the output voltage of the DC/DC result when a power supply to the control circuit is turned off.Type: ApplicationFiled: May 23, 2005Publication date: December 1, 2005Applicant: FIJITSU LIMITEDInventors: Mitsuo Saeki, Hidetoshi Yano, Hidekiyo Ozawa, Seiya Kitagawa, Toshiyuki Matsuyama, Takashi Matsumoto, Kyuichi Takimoto, Yoshiaki Sano
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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: 6911806Abstract: A direct-current to direct-current conversion (DC/DC) apparatus includes a control circuit having an error amplifier for voltage control, basing the conversion 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 carries out the pulse width modulation control. Furthermore, the control circuit includes a circuit for discharging charges corresponding to the output voltage of the DC/DC result when a power supply to the control circuit is turned off.Type: GrantFiled: December 15, 2003Date of Patent: June 28, 2005Assignee: Fujitsu LimitedInventors: Mitsuo Saeki, Hidetoshi Yano, Hidekiyo Ozawa, Seiya Kitagawa, Toshiyuki Matsuyama, Takashi Matsumoto, Kyuichi Takimoto, Yoshiaki Sano
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Patent number: RE42114Abstract: A control system for charging enabling efficient charging of rechargeable batteries in an electronic apparatus which charges its rechargeable batteries by using a charger circuit when driving the apparatus by using an external power source, including first detecting unit for detecting a differential value between a maximum permissible charging current allowed by the rechargeable batteries and a charging current flowing to the rechargeable batteries; second detecting unit for detecting a maximum usable current by detecting a differential value between a maximum supplyable current allowed by the external power source and the current consumption of the apparatus; third detecting unit for detecting a differential value between a maximum useable current and the charging current flowing to the rechargeable batteries; and control unit for controlling the system in accordance with the differential values detected by the first and third detecting units so that the charger circuit generates the maximum charging currentType: GrantFiled: April 12, 2000Date of Patent: February 8, 2011Assignee: Fujitsu Semiconductor LimitedInventors: Kouichi Matsuda, Mitsuo Saeki, Nobuo Tanaka, Hidekiyo Ozawa
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Patent number: RE43911Abstract: A control system for charging enabling efficient charging of rechargeable batteries in an electronic apparatus which charges its rechargeable batteries by using a charger circuit when driving the apparatus by using an external power source, including first detecting unit for detecting a differential value between a maximum permissible charging current allowed by the rechargeable batteries and a charging current flowing to the rechargeable batteries; second detecting unit for detecting a maximum usable current by detecting a differential value between a maximum supplyable current allowed by the external power source and the current consumption of the apparatus; third detecting unit for detecting a differential value between a maximum useable current and the charging current flowing to the rechargeable batteries; and control unit for controlling the system in accordance with the differential values detected by the first and third detecting units so that the charger circuit generates the maximum charging currentType: GrantFiled: March 7, 2003Date of Patent: January 8, 2013Assignee: Fujitsu Semiconductor LimitedInventors: Kouichi Matsuda, Mitsuo Saeki, Nobuo Tanaka, Hidekiyo Ozawa