Patents by Inventor Kiyofumi Kitai

Kiyofumi Kitai 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).

  • Publication number: 20220385208
    Abstract: A power conversion device including a switching element includes: a temperature change estimation unit estimating temperature change in a semiconductor chip containing the switching element; a number calculator calculating the number of power cycles to fracture of the semiconductor chip due to power cycles; and a degradation degree calculator computing a degree of degradation of the semiconductor chip caused by the power cycles. The temperature change estimation unit calculates a maximum value and a minimum value of temperature of the semiconductor chip in one power cycle based on a first threshold of temperature fall allowed when it is determined that the temperature of the semiconductor chip is rising, and a second threshold of temperature rise allowed when it is determined that the temperature of the semiconductor chip is falling. The number calculator calculates the number of power cycles to fracture based on the maximum value and the minimum value.
    Type: Application
    Filed: November 29, 2019
    Publication date: December 1, 2022
    Applicant: Mitsubishi Electric Corporation
    Inventors: Daiki MATSUOKA, Tatsuki MATSUNAGA, Shizuri TAMURA, Kiyofumi KITAI, Shoji ADACHI, Kosuke FUJIMOTO
  • Patent number: 11322430
    Abstract: A semiconductor device and a semiconductor module which can be reduced in size while ensuing insulation are provided. In the semiconductor device, a lead frame on which a circuit pattern is formed is provided on an insulation substrate; the circuit pattern of the lead frame is joined to the back-side electrode of a semiconductor chip via a solder layer, and the lead frame is electrically connected with the top-side electrode of the semiconductor chip via a wire; the lead frame 1 includes a terminal inside a mold-sealing resin and a terminal exposed to a space outside the mold-sealing resin, and the terminal is connected to a terminal block via a solder layer; and the lead frame, the insulation substrate, the semiconductor chip and the terminal block are integrally molded and sealed by the mold-sealing resin.
    Type: Grant
    Filed: January 23, 2018
    Date of Patent: May 3, 2022
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Hodaka Rokubuichi, Kuniyuki Sato, Kiyofumi Kitai, Yasuyuki Sanda
  • Patent number: 11152280
    Abstract: A semiconductor device includes a power module unit, a fin base, and a plurality of radiator fins. The power module unit and the fin base are integrated together, with a recess-projection portion formed on the power module unit being fitted to a recess-projection portion formed on the fin base. The plurality of radiator fins are integrally fitted on a heat radiation diffusion portion of the fin base.
    Type: Grant
    Filed: November 16, 2017
    Date of Patent: October 19, 2021
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Yasuyuki Sanda, Dai Nakajima, Haruna Tada, Hodaka Rokubuichi, Kiyofumi Kitai
  • Patent number: 11107745
    Abstract: A semiconductor device includes a power module unit, a fin base, and a plurality of radiator fins. The power module unit and the fin base are integrated together, with a recess-projection portion formed on the power module unit being fitted to a recess-projection portion formed on the fin base. The plurality of radiator fins are integrally fitted on a heat radiation diffusion portion of the fin base.
    Type: Grant
    Filed: November 16, 2017
    Date of Patent: August 31, 2021
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Yasuyuki Sanda, Dai Nakajima, Haruna Tada, Hodaka Rokubuichi, Kiyofumi Kitai
  • Publication number: 20200176361
    Abstract: A semiconductor device and a semiconductor module which can be reduced in size while ensuing insulation are provided. In the semiconductor device, a lead frame on which a circuit pattern is formed is provided on an insulation substrate; the circuit pattern of the lead frame is joined to the back-side electrode of a semiconductor chip via a solder layer, and the lead frame is electrically connected with the top-side electrode of the semiconductor chip via a wire; the lead frame 1 includes a terminal inside a mold-sealing resin and a terminal exposed to a space outside the mold-sealing resin, and the terminal is connected to a terminal block via a solder layer; and the lead frame, the insulation substrate, the semiconductor chip and the terminal block are integrally molded and sealed by the mold-sealing resin.
    Type: Application
    Filed: January 23, 2018
    Publication date: June 4, 2020
    Applicant: Mitsubishi Electric Corporation
    Inventors: Hodaka ROKUBUICHI, Kuniyuki SATO, Kiyofumi KITAI, Yasuyuki SANDA
  • Patent number: 10529643
    Abstract: A semiconductor device that reduces the deformation of a metal base due to pressure during transfer molding, to thereby suppress the occurrence of cracks in an insulating layer to achieve high electrical reliability. The semiconductor device includes: a metal member provided, on its lower surface, with a projection and a depression, and a projecting peripheral portion surrounding the projection and the depression and having a height greater than or equal to a height of the projection of the projection and the depression; an insulating layer formed on an upper surface of the metal member; a metal layer formed on an upper surface of the insulating layer; a semiconductor element joined to an upper surface of the metal layer; and a sealing resin to seal the semiconductor element, the metal layer, the insulating layer and the metal member.
    Type: Grant
    Filed: September 20, 2016
    Date of Patent: January 7, 2020
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kei Yamamoto, Hodaka Rokubuichi, Dai Nakajima, Kiyofumi Kitai, Yoichi Goto
  • Patent number: 10461010
    Abstract: The power module of the invention includes a power element, a metal base for dissipating heat from the power element, a lead frame electrically connected to electrodes of the power element, and a resin enclosure that encapsulates the power element so that one surface of the metal base and a part of the lead frame are exposed from the enclosure. The resin enclosure of the power module includes: a body portion in which the power element and a part of the lead frame are placed, and at a bottom surface of which the one surface of the metal base is exposed; and a rib portion which is placed on the bottom surface of the body portion so as to surround an outer periphery of the metal base, and is formed to protrude from the bottom surface of the body portion in a direction perpendicular to the bottom surface.
    Type: Grant
    Filed: March 27, 2017
    Date of Patent: October 29, 2019
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Hiroyuki Yoshihara, Dai Nakajima, Masaki Goto, Kiyofumi Kitai
  • Publication number: 20190295919
    Abstract: A semiconductor device includes a power module unit, a fin base, and a plurality of radiator fins. The power module unit and the fin base are integrated together, with a recess-projection portion formed on the power module unit being fitted to a recess-projection portion formed on the fin base. The plurality of radiator fins are integrally fitted on a heat radiation diffusion portion of the fin base.
    Type: Application
    Filed: November 16, 2017
    Publication date: September 26, 2019
    Applicant: Mitsubishi Electric Corporation
    Inventors: Yasuyuki Sanda, Dai Nakajima, Haruna Tada, Hodaka Rokubuichi, Kiyofumi Kitai
  • Publication number: 20190067154
    Abstract: The power module of the invention includes a power element, a metal base for dissipating heat from the power element, a lead frame electrically connected to electrodes of the power element, and a resin enclosure that encapsulates the power element so that one surface of the metal base and a part of the lead frame are exposed from the enclosure. The resin enclosure of the power module includes: a body portion in which the power element and a part of the lead frame are placed, and at a bottom surface of which the one surface of the metal base is exposed; and a rib portion which is placed on the bottom surface of the body portion so as to surround an outer periphery of the metal base, and is formed to protrude from the bottom surface of the body portion in a direction perpendicular to the bottom surface.
    Type: Application
    Filed: March 27, 2017
    Publication date: February 28, 2019
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Hiroyuki Yoshihara, Dai Nakajima, Masaki Goto, Kiyofumi Kitai
  • Publication number: 20180261520
    Abstract: A semiconductor device that reduces the deformation of a metal base due to pressure during transfer molding, to thereby suppress the occurrence of cracks in an insulating layer to achieve high electrical reliability. The semiconductor device includes: a metal member provided, on its lower surface, with a projection and a depression, and a projecting peripheral portion surrounding the projection and the depression and having a height greater than or equal to a height of the projection of the projection and the depression; an insulating layer formed on an upper surface of the metal member; a metal layer formed on an upper surface of the insulating layer; a semiconductor element joined to an upper surface of the metal layer; and a sealing resin to seal the semiconductor element, the metal layer, the insulating layer and the metal member.
    Type: Application
    Filed: September 20, 2016
    Publication date: September 13, 2018
    Applicant: Mitsubishi Electric Corporation
    Inventors: Kei YAMAMOTO, Hodaka ROKUBUICHI, Dai NAKAJIMA, Kiyofumi KITAI, Yoichi GOTO
  • Patent number: 9892992
    Abstract: A swaged heat includes a fin base having an outer periphery, and formed with a first fin insert groove and a second fin insert groove interposing a swage portion of a bi-forked shape in between, a first fin fixed to the first fin insert groove of the fin base using the swage portion, a second fin fixed to the second fin insert groove of the fin base using the swage portion, a panel having an opening portion, and placed on the outer periphery of the fin base. The thickness of the outer periphery is smaller than that of the fin base.
    Type: Grant
    Filed: September 19, 2014
    Date of Patent: February 13, 2018
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Yasuyuki Sanda, Dai Nakajima, Hiroyuki Yoshihara, Kiyofumi Kitai, Kiyoshi Shibata
  • Patent number: 9685399
    Abstract: A power semiconductor device is provided with a base plate thermally connected to the power semiconductor element for heat generated from the power semiconductor element to be conducted to heat radiation fins. An electrically conductive member fixed to the base plate is electrically conducted to the base plate and is connected to ground, and has projections fitted into notches provided in the electrically conductive member. By deforming the projections, the electrically conductive member is fixed to the base plate and electrical conduction can be secured. With this arrangement, noise radiated from the power semiconductor element is reduced and malfunction of the power semiconductor element is suppressed.
    Type: Grant
    Filed: December 5, 2013
    Date of Patent: June 20, 2017
    Assignee: Mitsubishi Electric Corporation
    Inventors: Toru Kimura, Yoichi Goto, Kiyofumi Kitai
  • Publication number: 20160300785
    Abstract: Projections 35 provided in a base plate 22 are fitted into notches provided in an electrically conductive member 12, and then the base plate 22 is fixed to the electrically conductive member 12 by deforming the projections 35 and the electrically conductive member 12 is connected to earth ground, so that noise radiated from a power semiconductor element 21 is reduced and malfunction of the power semiconductor element 21 is suppressed.
    Type: Application
    Filed: December 5, 2013
    Publication date: October 13, 2016
    Applicant: Mitsubishi Electric Corporation
    Inventors: Toru Kimura, Yoichi Goto, Kiyofumi Kitai
  • Publication number: 20160225691
    Abstract: A swaged heat includes a fin base having an outer periphery, and formed with a first fin insert groove and a second fin insert groove interposing a swage portion of a bi-forked shape in between, a first fin fixed to the first fin insert groove of the fin base using the swage portion, a second fin fixed to the second fin insert groove of the fin base using the swage portion, a panel having an opening portion, and placed on the outer periphery of the fin base. The thickness of the outer periphery is smaller than that of the fin base.
    Type: Application
    Filed: September 19, 2014
    Publication date: August 4, 2016
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Yasuyuki SANDA, Dai NAKAJIMA, Hiroyuki YOSHIHARA, Kiyofumi KITAI, Kiyoshi SHIBATA
  • Publication number: 20150001702
    Abstract: To obtain a semiconductor module that can fix itself onto a fixing object while enabling further miniaturization, in addition to alleviating load applied on a molded resin, a semiconductor module includes: a semiconductor element; a placing frame on which the semiconductor element is placed; a control substrate onto which a control component for controlling the semiconductor element is mounted; and a molded resin in which the semiconductor element, the placing frame, and the control substrate are integrally molded. Fixing bases exposed from the molded resin are provided on the control substrate for fixing the semiconductor module onto a chassis.
    Type: Application
    Filed: May 17, 2012
    Publication date: January 1, 2015
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Yuki Kawauchi, Kiyofumi Kitai
  • Publication number: 20140035122
    Abstract: A power semiconductor device includes: a mold unit that includes a power semiconductor element, a base plate, and a mold unit, the power semiconductor element being mounted on one surface of the base plate, a convex portion being formed on an other surface of the base plate, the convex portion including a plurality of grooves, the mold unit having a mold resin with which the power semiconductor element is sealed in such a manner as to expose the convex portion; a plurality of radiation fins inserted into the grooves, respectively, and fixedly attached to the base plate by swaging; and a metal plate that includes a opening into which the convex portion is inserted, the metal plate being arranged between the mold unit and the radiation fins with the convex portion inserted into the opening, wherein the metal plate includes a protrusion that protrudes from an edge of the opening and that digs into a side surface of the convex portion when the convex portion is inserted into the opening.
    Type: Application
    Filed: July 31, 2012
    Publication date: February 6, 2014
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Shigeyuki Nakazato, Yoichi Goto, Kiyofumi Kitai, Toru Kimura
  • Patent number: 8643171
    Abstract: A power semiconductor device includes: a mold unit that includes a power semiconductor element, a base plate, and a mold unit, the power semiconductor element being mounted on one surface of the base plate, a convex portion being formed on an other surface of the base plate, the convex portion including a plurality of grooves, the mold unit having a mold resin with which the power semiconductor element is sealed in such a manner as to expose the convex portion; a plurality of radiation fins inserted into the grooves, respectively, and fixedly attached to the base plate by swaging; and a metal plate that includes a opening into which the convex portion is inserted, the metal plate being arranged between the mold unit and the radiation fins with the convex portion inserted into the opening, wherein the metal plate includes a protrusion that protrudes from an edge of the opening and that digs into a side surface of the convex portion when the convex portion is inserted into the opening.
    Type: Grant
    Filed: July 31, 2012
    Date of Patent: February 4, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventors: Shigeyuki Nakazato, Yoichi Goto, Kiyofumi Kitai, Toru Kimura