Patents by Inventor Kimihiro Nishijima

Kimihiro Nishijima 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: 10284075
    Abstract: An overvoltage protection circuit is provided which is connected between a rectifier circuit and a load including an input capacitor element connected to both ends of the load. The overvoltage protection circuit includes a semiconductor switch connected between the rectifier circuit and the load, and a control circuit controls the semiconductor switch. When the rectified voltage exceeds a predetermined value, the control circuit turns off the semiconductor switch, and detects a voltage potential difference between both ends of the semiconductor switch, and then, for an interval when the voltage potential difference is zero or a predetermined minute value, the control circuit generates a control voltage for turning on the semiconductor switch, and outputs the control voltage to a control terminal of the semiconductor switch. The overvoltage protection circuit includes a current change circuit that gradually changes a current flowing through the semiconductor switch.
    Type: Grant
    Filed: August 1, 2018
    Date of Patent: May 7, 2019
    Assignees: RICOH ELECTRONIC DEVICES CO., LTD., NATIONAL UNIVERSITY CORPORATION OITA UNIVERSITY
    Inventors: Shohtaroh Sohma, Yuji Takeyama, Kimihiro Nishijima
  • Publication number: 20190058323
    Abstract: An overvoltage protection circuit is provided which is connected between a rectifier circuit and a load including an input capacitor element connected to both ends of the load. The overvoltage protection circuit includes a semiconductor switch connected between the rectifier circuit and the load, and a control circuit controls the semiconductor switch. When the rectified voltage exceeds a predetermined value, the control circuit turns off the semiconductor switch, and detects a voltage potential difference between both ends of the semiconductor switch, and then, for an interval when the voltage potential difference is zero or a predetermined minute value, the control circuit generates a control voltage for turning on the semiconductor switch, and outputs the control voltage to a control terminal of the semiconductor switch. The overvoltage protection circuit includes a current change circuit that gradually changes a current flowing through the semiconductor switch.
    Type: Application
    Filed: August 1, 2018
    Publication date: February 21, 2019
    Applicants: RICOH ELECTRONIC DEVICES CO., LTD., NATIONAL UNIVERSITY CORPORATION OITA UNIVERSITY
    Inventors: Shohtaroh SOHMA, Yuji TAKEYAMA, Kimihiro NISHIJIMA
  • Patent number: 9979271
    Abstract: In a power converter, switch-off of the synchronous rectification switch while the auxiliary switch is on causes the first capacitance of the main switch and the second capacitance of the synchronous rectification switch to resonate with the inductance of the second magnetic component. A parameter obtainer detects a voltage across a selected one of the main switch and the synchronous rectification switch, and obtains a parameter indicative of a corresponding one of rising and falling waveforms of the voltage across the selected switch while the selected switch is switched. A controller controls a switching control signal for the auxiliary switch to adjust switch-on timing of the auxiliary switch as a function of the parameter obtained by the parameter obtainer.
    Type: Grant
    Filed: February 16, 2017
    Date of Patent: May 22, 2018
    Assignees: DENSO CORPORATION, NATIONAL UNIVERSITY CORPORATION OITA UNIVERTY
    Inventors: Masaya Takahashi, Nobuhisa Yamaguchi, Kimihiro Nishijima
  • Patent number: 9960678
    Abstract: In a power converter, a first electrical path connects between the series resonant circuit and a selected terminal from the high- and low-side input and output terminals of the power converter. An auxiliary diode is provided on one of the series resonant circuit and the first electrical path. An auxiliary switch, when turned on, causes an inductor current to flow through the auxiliary diode to the resonance inductor, thus storing electromagnetic energy into the resonance inductor, and causes the resonance inductor and the capacitance component of the series resonant circuit to resonate with each other. A second electrical path bypasses the auxiliary switch for flow of the inductor current. A discharge unit is provided on the second electrical path. The discharge unit is activated to discharge the electromagnetic energy stored in the resonance inductor via the second electrical path.
    Type: Grant
    Filed: June 21, 2017
    Date of Patent: May 1, 2018
    Assignees: DENSO CORPORATION, NATIONAL UNIVERSITY CORPORATION OITA UNIVERSITY
    Inventors: Eisuke Takahashi, Masaya Takahashi, Kimihiro Nishijima
  • Publication number: 20170373592
    Abstract: In a power converter, a first electrical path connects between the series resonant circuit and a selected terminal from the high- and low-side input and output terminals of the power converter. An auxiliary diode is provided on one of the series resonant circuit and the first electrical path. An auxiliary switch, when turned on, causes an inductor current to flow through the auxiliary diode to the resonance inductor, thus storing electromagnetic energy into the resonance inductor, and causes the resonance inductor and the capacitance component of the series resonant circuit to resonate with each other. A second electrical path bypasses the auxiliary switch for flow of the inductor current. A discharge unit is provided on the second electrical path. The discharge unit is activated to discharge the electromagnetic energy stored in the resonance inductor via the second electrical path.
    Type: Application
    Filed: June 21, 2017
    Publication date: December 28, 2017
    Applicants: DENSO CORPORATION, NATIONAL UNIVERSITY CORPORATION OITA UNIVERSITY
    Inventors: Eisuke TAKAHASHI, Masaya TAKAHASHI, Kimihiro NISHIJIMA
  • Publication number: 20170237332
    Abstract: In a power converter, switch-off of the synchronous rectification switch while the auxiliary switch is on causes the first capacitance of the main switch and the second capacitance of the synchronous rectification switch to resonate with the inductance of the second magnetic component. A parameter obtainer detects a voltage across a selected one of the main switch and the synchronous rectification switch, and obtains a parameter indicative of a corresponding one of rising and falling waveforms of the voltage across the selected switch while the selected switch is switched. A controller controls a switching control signal for the auxiliary switch to adjust switch-on timing of the auxiliary switch as a function of the parameter obtained by the parameter obtainer.
    Type: Application
    Filed: February 16, 2017
    Publication date: August 17, 2017
    Applicants: DENSO CORPORATION, NATIONAL UNIVERSITY CORP. OITA UNIVERSITY
    Inventors: Masaya TAKAHASHI, Nobuhisa YAMAGUCHI, Kimihiro NISHIJIMA
  • Patent number: 8379421
    Abstract: When a commercial power supply E operates normally, converter sections PFC1, PFC2 connected in parallel to each other can operate to approximate the input current from the commercial power supply E to the waveform and phase of the input voltage to correct a power factor while supplying stabilized output voltages Vo1, Vo2 to a load. When the voltage of the commercial power supply E drops, the smoothing capacitor Co1 operates as an input power supply to power the converter section PFC2, which allows the smoothing capacitor Co2 to supply the stabilized output voltage Vo2 to the load.
    Type: Grant
    Filed: February 24, 2010
    Date of Patent: February 19, 2013
    Assignee: Oita University
    Inventor: Kimihiro Nishijima
  • Patent number: 8278783
    Abstract: To provide a power supply apparatus that can supply a large current and a small current to a load circuit in a switchable manner, with a minimum circuit scale and an efficient use of electronic devices and elements contained in conventionally used power supply apparatuses.
    Type: Grant
    Filed: December 22, 2009
    Date of Patent: October 2, 2012
    Assignee: Oita University
    Inventor: Kimihiro Nishijima
  • Publication number: 20120120696
    Abstract: [OBJECT] A PFC converter is provided in which a smoothing capacitor can be small in size and a power supply circuit connected to the subsequent stages can be simple, efficient, low-cost, small in size and lightweight through the functionality of the PFC converter itself of preventing the output voltage from dropping in the event of a power failure or instantaneous power failure of an input power supply. [SOLUTION] When a commercial power supply E operates normally, converter sections PFC1, PFC2 connected in parallel to each other can operate to approximate the input current from the commercial power supply E to the waveform and phase of the input voltage to correct power factor while supplying stabilized output voltages Vo1, Vo2 to a load. On the other hand, when the voltage of the commercial power supply E drops, the smoothing capacitor Co1 operates as input power supply to power the converter section PFC2, which allows the smoothing capacitor Co2 to supply the stabilized output voltage Vo2 to the load.
    Type: Application
    Filed: February 24, 2010
    Publication date: May 17, 2012
    Inventor: Kimihiro Nishijima
  • Publication number: 20110260706
    Abstract: To provide a power supply apparatus that can supply a large current and a small current to a load circuit in a switchable manner, with a minimum circuit scale and an efficient use of electronic devices and elements contained in conventionally used power supply apparatuses.
    Type: Application
    Filed: December 22, 2009
    Publication date: October 27, 2011
    Inventor: Kimihiro Nishijima
  • Publication number: 20110227546
    Abstract: To eliminate the problem that a magnetic deflection is caused in a transformer even when a coupled inductor converter is in a stationary operation state, provided is a DC-DC converter including a first series circuit portion formed by a first switching transistor, a first capacitor, a first inductor, and a second capacitor which are connected to a DC power in series in this order, and a second series circuit portion formed by a second switching transistor and a second inductor which are connected in series in this order, the second series circuit portion is connected in parallel to the first capacitor and the first inductor, and the first inductor and the second inductor constitute a coupled inductor having a plurality of windings and a common magnetic core.
    Type: Application
    Filed: October 28, 2009
    Publication date: September 22, 2011
    Applicants: OITA University, Hitachi Computer Peripherals Co., Ltd.
    Inventors: Kimihiro Nishijima, Kosuke Abe
  • Patent number: 7586759
    Abstract: The number of switches on the primary winding side of a transformer is decreased and ripples contained in the output voltage are greatly reduced. In a state I, Sia and Sib are switched ON, in a state II, Sim and Sia are switched ON, in a state III, Sia and Sib are switched ON, and in a state IV, Sim and Sib are switched ON. As a result, in the states I to III, a transformer Trsa is connected to a capacitor Ci, in the state IV, the transformer Trsa is connected to an input power source Vi supplying an electric current in the direction opposite to that of the capacitor Ci. Further, in states I, III, and IV, the transformer Trsb is connected to the capacitor Ci, and in state II, the transformer Trsb is connected to the input power source Vi supplying an electric current in the direction opposite to that of the capacitor Ci.
    Type: Grant
    Filed: September 17, 2004
    Date of Patent: September 8, 2009
    Assignee: Taiyo Yuden Co.
    Inventors: Kosuke Harada, Kimihiro Nishijima
  • Publication number: 20050226008
    Abstract: The number of switches on the primary winding side of a transformer is decreased and ripples contained in the output voltage are greatly reduced. In a state I, Sia and Sib are switched ON, in a state II, Sim and Sia are switched ON, in a state III, Sia and Sib are switched ON, and in a state IV, Sim and Sib are switched ON. As a result, in the states I to III, a transformer Trsa is connected to a capacitor Ci, in the state IV, the transformer Trsa is connected to an input power source Vi supplying an electric current in the direction opposite to that of the capacitor Ci. Further, in states I, III, and IV, the transformer Trsb is connected to the capacitor Ci, and in state II, the transformer Trsb is connected to the input power source Vi supplying an electric current in the direction opposite to that of the capacitor Ci.
    Type: Application
    Filed: September 17, 2004
    Publication date: October 13, 2005
    Inventors: Kosuke Harada, Kimihiro Nishijima