Patents by Inventor Ryuusei FUJITA

Ryuusei FUJITA 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: 11296191
    Abstract: Dielectric breakdown resistance of a power module including a SiC-IGBT and a SiC diode is improved. The power module includes a SiC-IGBT 110 and a SiC diode 111, and a film thickness of a resin layer 323 covering an upper portion of an electric field relaxation region 320 of the SiC-IGBT 110 is larger than a chip thickness of the SiC-IGBT 110, that is, for example, 200 ?m or more.
    Type: Grant
    Filed: October 2, 2017
    Date of Patent: April 5, 2022
    Assignee: HITACHI, LTD.
    Inventors: Ryuusei Fujita, Naoki Watanabe, Yuan Bu
  • Publication number: 20210351271
    Abstract: Dielectric breakdown resistance of a power module including a SiC-IGBT and a SiC diode is improved. The power module includes a SiC-IGBT 110 and a SiC diode 111, and a film thickness of a resin layer 323 covering an upper portion of an electric field relaxation region 320 of the SiC-IGBT 110 is larger than a chip thickness of the SiC-IGBT 110, that is, for example, 200 ?m or more.
    Type: Application
    Filed: October 2, 2017
    Publication date: November 11, 2021
    Inventors: Ryuusei FUJITA, Naoki WATANABE, Yuan BU
  • Patent number: 10692860
    Abstract: An object of the present invention is to increase the reliability of a power module and a power converter and to extend their life. In order to achieve this, a power module includes: two switching devices each including a diode and a transistor, the two switching devices being electrically connected in parallel; and an insulating substrate on which the two switching devices are mounted. Further, a gate electrode of MOFET that each of the two switching device has is electrically connected to a gate resistance. Further, of the two switching devices, the gate resistance that is electrically connected to the switching device, whose current value is smaller when a predetermined voltage is applied in the forward direction of the body diode, is greater than the gate resistance that is electrically connected to the switching device whose current value is larger.
    Type: Grant
    Filed: December 12, 2018
    Date of Patent: June 23, 2020
    Assignee: HITACHI, LTD.
    Inventors: Ryuusei Fujita, Kumiko Konishi, Akio Shima
  • Patent number: 10511301
    Abstract: A gate drive circuit to prevent a false turn-on phenomenon includes a first, second, third and fourth switching element, and a capacitor. A source of the first switching element is connected to a first voltage, and a drain of the same is connected to the main switching element's gate electrode. A source of the second switching element is connected to a second voltage, and a drain of the same is connected to the gate electrode. A source of the third switching element is connected to the first voltage, and a drain of the same is connected to a first electrode of the capacitor. A source of the fourth switching element is connected to the second voltage, and a drain of the same is connected to the first electrode and to the drain of the third switching element. A second electrode of the capacitor is connected to the gate electrode.
    Type: Grant
    Filed: June 24, 2016
    Date of Patent: December 17, 2019
    Assignee: Hitachi, Ltd.
    Inventors: Satoru Akiyama, Ryuusei Fujita
  • Patent number: 10367090
    Abstract: Provided is a silicon carbide semiconductor device in which SiC-MOSFETs are formed within an active region of an n-type silicon carbide semiconductor substrate, and a p+-type semiconductor region is formed on an upper surface of an epitaxial layer so as to surround the active region.
    Type: Grant
    Filed: July 2, 2018
    Date of Patent: July 30, 2019
    Assignee: Hitachi, Ltd.
    Inventors: Kumiko Konishi, Ryuusei Fujita, Kazuki Tani, Akio Shima
  • Publication number: 20190198495
    Abstract: An object of the present invention is to increase the reliability of a power module and a power converter and to extend their life. In order to achieve this, a power module includes: two switching devices each including a diode and a transistor, the two switching devices being electrically connected in parallel; and an insulating substrate on which the two switching devices are mounted. Further, a gate electrode of MOFET that each of the two switching device has is electrically connected to a gate resistance. Further, of the two switching devices, the gate resistance that is electrically connected to the switching device, whose current value is smaller when a predetermined voltage is applied in the forward direction of the body diode, is greater than the gate resistance that is electrically connected to the switching device whose current value is larger.
    Type: Application
    Filed: December 12, 2018
    Publication date: June 27, 2019
    Inventors: Ryuusei FUJITA, Kumiko KONISHI, Akio SHIMA
  • Publication number: 20190115465
    Abstract: Provided is a silicon carbide semiconductor device in which SiC-MOSFETs are formed within an active region of an n-type silicon carbide semiconductor substrate, and a p+-type semiconductor region is formed on an upper surface of an epitaxial layer so as to surround the active region.
    Type: Application
    Filed: July 2, 2018
    Publication date: April 18, 2019
    Applicant: HITACHI, LTD.
    Inventors: Kumiko KONISHI, Ryuusei FUJITA, Kazuki TANI, Akio SHIMA
  • Publication number: 20180375509
    Abstract: A gate drive circuit to prevent a false turn-on phenomenon includes a first, second, third and fourth switching element, and a capacitor. A source of the first switching element is connected to a first voltage, and a drain of the same is connected to the main switching element's gate electrode. A source of the second switching element is connected to a second voltage, and a drain of the same is connected to the gate electrode. A source of the third switching element is connected to the first voltage, and a drain of the same is connected to a first electrode of the capacitor. A source of the fourth switching element is connected to the second voltage, and a drain of the same is connected to the first electrode and to the drain of the third switching element. A second electrode of the capacitor is connected to the gate electrode.
    Type: Application
    Filed: June 24, 2016
    Publication date: December 27, 2018
    Applicant: HITACHI, LTD.
    Inventors: Satoru AKIYAMA, Ryuusei FUJITA
  • Patent number: 10115700
    Abstract: The object of the present invention is to compensate for a difference in threshold voltage between a plurality of switching devices incorporated in a power module. The present invention solves the subject described above by mounting a switching device having a high threshold voltage in comparison with a different switching device at a location at which the temperature of the power module during operation is higher than that at another location at which the different switching device is mounted. Eventually, a power conversion apparatus of a high performance and a vehicle drive apparatus of a high performance can be provided.
    Type: Grant
    Filed: March 13, 2015
    Date of Patent: October 30, 2018
    Assignee: Hitachi, Ltd.
    Inventors: Ryuusei Fujita, Satoru Akiyama, Hiroshi Kageyama, Toru Masuda, Ayumu Hatanaka, Akio Shima
  • Publication number: 20180026009
    Abstract: The object of the present invention is to compensate for a difference in threshold voltage between a plurality of switching devices incorporated in a power module. The present invention solves the subject described above by mounting a switching device having a high threshold voltage in comparison with a different switching device at a location at which the temperature of the power module during operation is higher than that at another location at which the different switching device is mounted. Eventually, a power conversion apparatus of a high performance and a vehicle drive apparatus of a high performance can be provided.
    Type: Application
    Filed: March 13, 2015
    Publication date: January 25, 2018
    Inventors: Ryuusei FUJITA, Satoru AKIYAMA, Hiroshi KAGEYAMA, Toru MASUDA, Ayumu HATANAKA, Akio SHIMA