Patents by Inventor Kazumi Takagiwa

Kazumi Takagiwa 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: 11699764
    Abstract: A semiconductor device includes: a semiconductor layer of a first conductivity-type; a well region of a second conductivity-type provided at an upper part of the semiconductor layer; a base region of the second conductivity-type provided at an upper part of the well region; a carrier supply region of the first conductivity-type provided at an upper part of the base region; a drift region of the first conductivity-type provided separately from the base region; a carrier reception region of the first conductivity-type provided at an upper part of the drift region; a gate electrode provided on a top surface of the well region interposed between the base region and the drift region via a gate insulating film; and a punch-through prevention region of the second conductivity-type provided at the upper part of the well region and having an impurity concentration different from the impurity concentration of the base region.
    Type: Grant
    Filed: January 31, 2022
    Date of Patent: July 11, 2023
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Kazumi Takagiwa, Hitoshi Sumida
  • Patent number: 11581886
    Abstract: There is provided a current detection circuit including: a current detection unit that detects a control current flowing between a control terminal of a semiconductor element of voltage-controlled type having a current detection terminal, and a drive circuit; an overcurrent detection unit that detects an overcurrent based on a result of comparing a sense voltage with a sense reference voltage, the sense voltage corresponding to a sense current flowing through the current detection terminal; and an adjustment unit that adjusts the sense reference voltage based on a detection result of the current detection unit.
    Type: Grant
    Filed: June 30, 2020
    Date of Patent: February 14, 2023
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Kazumi Takagiwa
  • Patent number: 11545970
    Abstract: There is provide a current detection circuit including: a current detection unit that detects a control current flowing between a control terminal of a semiconductor element of voltage-controlled type having a current detection terminal, and a drive circuit; an overcurrent detection unit that detects an overcurrent in response to a sense current exceeding an overcurrent threshold value, the sense current flowing through the current detection terminal; and an adjustment unit that sets, based on a detection result of the current detection unit, the overcurrent threshold value in a transient period during turn on and turn off of the semiconductor element to be higher than the overcurrent threshold value in a period other than the transient period.
    Type: Grant
    Filed: June 29, 2020
    Date of Patent: January 3, 2023
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Kazumi Takagiwa
  • Publication number: 20220285563
    Abstract: A semiconductor device includes: a semiconductor layer of a first conductivity-type; a well region of a second conductivity-type provided at an upper part of the semiconductor layer; a base region of the second conductivity-type provided at an upper part of the well region; a carrier supply region of the first conductivity-type provided at an upper part of the base region; a drift region of the first conductivity-type provided separately from the base region; a carrier reception region of the first conductivity-type provided at an upper part of the drift region; a gate electrode provided on a top surface of the well region interposed between the base region and the drift region via a gate insulating film; and a punch-through prevention region of the second conductivity-type provided at the upper part of the well region and having an impurity concentration different from the impurity concentration of the base region.
    Type: Application
    Filed: January 31, 2022
    Publication date: September 8, 2022
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Kazumi TAKAGIWA, Hitoshi SUMIDA
  • Publication number: 20210006242
    Abstract: There is provide a current detection circuit including: a current detection unit that detects a control current flowing between a control terminal of a semiconductor element of voltage-controlled type having a current detection terminal, and a drive circuit; an overcurrent detection unit that detects an overcurrent in response to a sense current exceeding an overcurrent threshold value, the sense current flowing through the current detection terminal; and an adjustment unit that sets, based on a detection result of the current detection unit, the overcurrent threshold value in a transient period during turn on and turn off of the semiconductor element to be higher than the overcurrent threshold value in a period other than the transient period.
    Type: Application
    Filed: June 29, 2020
    Publication date: January 7, 2021
    Inventor: Kazumi TAKAGIWA
  • Publication number: 20210006243
    Abstract: There is provided a current detection circuit including: a current detection unit that detects a control current flowing between a control terminal of a semiconductor element of voltage-controlled type having a current detection terminal, and a drive circuit; an overcurrent detection unit that detects an overcurrent based on a result of comparing a sense voltage with a sense reference voltage, the sense voltage corresponding to a sense current flowing through the current detection terminal; and an adjustment unit that adjusts the sense reference voltage based on a detection result of the current detection unit.
    Type: Application
    Filed: June 30, 2020
    Publication date: January 7, 2021
    Inventor: Kazumi TAKAGIWA
  • Patent number: 9667129
    Abstract: A power conversion device, including first and second semiconductor switching elements, first and second free wheeling diodes respectively connected in reverse parallel to the first and second semiconductor switching elements, and first and second drive circuits configured to respectively on/off drive the first and second semiconductor switching elements. The first and second semiconductor switching elements are connected in series to form a half bridge circuit and are respectively disposed on upper and lower arms of the half bridge circuit. The second drive circuit includes an alarm signal generation circuit configured to generate different alarm signals upon detecting overcurrent in different arms of the half bridge circuit.
    Type: Grant
    Filed: March 10, 2015
    Date of Patent: May 30, 2017
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Kazumi Takagiwa
  • Patent number: 9473133
    Abstract: Aspects of the present invention provides a device that is capable of accurately measuring an output current of a transistor, controls the drive of a switching element, by using an existing IC tester without any evaluation board improvement. The control device according to one aspect of the present invention has: a drive circuit, a plurality of transistors for controlling the drive of a switching element and a transistor operation controller. A transistor for turning the switching element OFF is configured by a plurality of transistors. The transistor operation controller, in a normal operation, performs ON/OFF control on the two transistors simultaneously or collectively by means of the same drive signal output from the drive circuit. In a test operation, the transistor operation controller sequentially selects one of the transistors and supplies the same drive signal to the selected transistor, to drive the transistors individually.
    Type: Grant
    Filed: December 14, 2012
    Date of Patent: October 18, 2016
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Kazumi Takagiwa
  • Patent number: 9246474
    Abstract: Embodiments of the invention provide a drive circuit including: a constant current source that generates a constant current; a switching circuit that connects a gate of the insulated gate switching element to a power supply potential side via the constant current source when turning the insulated gate switching element ON and connects the gate of the insulated gate switching element to a reference potential side via a discharge circuit when turning the insulated gate switching element OFF; a gate voltage detection circuit that detects a gate voltage of the insulated gate switching element; and a current mode selection circuit that switches a mode of the constant current source from a normal current mode to a low current consumption mode when detecting, based on the gate voltage detected by the gate voltage detection circuit, that the insulated gate switching element is turned ON.
    Type: Grant
    Filed: January 10, 2013
    Date of Patent: January 26, 2016
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Kazumi Takagiwa
  • Publication number: 20150188410
    Abstract: A power conversion device, including first and second semiconductor switching elements, first and second free wheeling diodes respectively connected in reverse parallel to the first and second semiconductor switching elements, and first and second drive circuits configured to respectively on/off drive the first and second semiconductor switching elements. The first and second semiconductor switching elements are connected in series to form a half bridge circuit and are respectively disposed on upper and lower arms of the half bridge circuit. The second drive circuit includes an alarm signal generation circuit configured to generate different alarm signals upon detecting overcurrent in different arms of the half bridge circuit.
    Type: Application
    Filed: March 10, 2015
    Publication date: July 2, 2015
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Kazumi TAKAGIWA
  • Patent number: 8917065
    Abstract: In aspects of the invention, a photocoupler output signal receiving circuit includes a first constant current circuit, connected between an input terminal and the high potential side of a direct current power source, that discharges current, a second constant current circuit, connected between the input terminal and the low potential side of the direct current power source, that takes in current, and switching elements that operate the first and second constant current circuits in a complementary way, wherein the switching elements are operated so that current is taken in by the second constant current circuit after a photocoupler is turned on, and are operated so that current is discharged by the first constant current circuit after the photocoupler is turned off, and a discharge current value in a current discharge period is reduced after a certain period elapses from the start of discharging.
    Type: Grant
    Filed: January 10, 2013
    Date of Patent: December 23, 2014
    Assignee: Fuji Electric Co., Ltd.
    Inventor: Kazumi Takagiwa
  • Publication number: 20050094302
    Abstract: On top of a silicon substrate, a polyimide film with a thickness of 10 ?m is formed. On top of this, a magnetic thin film that is a polyimide film containing Fe fine particles and that has a thickness of 20 ?m is formed. On top of this magnetic thin film, a patterned Ti/Au film and a Ti/Au connection conductor are formed. On top of this, a polyimide film with a thickness of 10 ?m, and a Cu coil with a height 35 ?m, width 90 ?m, space 25 ?m, and a polyimide layer that fills the spaces in the Cu coil are formed. On top of this, via a polyimide film with a thickness of 10 ?m, a magnetic thin film that is a polyimide film containing Fe particles and that has a thickness of 20 ?m is formed. This thin film inductor has a small alternating current resistance. The present invention provides a magnetic thin film that is well suited for mass production, can be manufactured easily, can be made into a thick film, has soft magnetic qualities, and is inexpensive.
    Type: Application
    Filed: December 14, 2004
    Publication date: May 5, 2005
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Kazuo Matsuzaki, Taku Furuta, Kazumi Takagiwa, Zenchi Hayashi
  • Patent number: 6835576
    Abstract: On top of a silicon substrate, a polyimide film with a thickness of 10 &mgr;m is formed. On top of this, a magnetic thin film that is a polyimide film containing Fe fine particles and that has a thickness of 20 &mgr;m is formed. On top of this magnetic thin film, a patterned Ti/Au film and a Ti/Au connection conductor are formed. On top of this, a polyimide film with a thickness of 10 &mgr;m, and a Cu coil with a height 35 &mgr;m, width 90 &mgr;m, space 25 &mgr;m, and a polyimide layer that fills the spaces in the Cu coil are formed. On top of this, via a polyimide film with a thickness of 10 &mgr;m, a magnetic thin film that is a polyimide film containing Fe particles and that has a thickness of 20 &mgr;m is formed. This thin film inductor has a small alternating current resistance. The present invention provides a magnetic thin film that is well suited for mass production, can be manufactured easily, can be made into a thick film, has soft magnetic qualities, and is inexpensive.
    Type: Grant
    Filed: May 1, 2001
    Date of Patent: December 28, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Kazuo Matsuzaki, Taku Furuta, Kazumi Takagiwa, Zenchi Hayashi
  • Publication number: 20020090755
    Abstract: On top of a silicon substrate, a polyimide film with a thickness of 10 &mgr;m is formed. On top of this, a magnetic thin film that is a polyimide film containing Fe fine particles and that has a thickness of 20 &mgr;m is formed. On top of this magnetic thin film, a patterned Ti/Au film and a Ti/Au connection conductor are formed. On top of this, a polyimide film with a thickness of 10 &mgr;m, and a Cu coil with a height 35 &mgr;m, width 90 &mgr;m, space 25 &mgr;m, and a polyimide layer that fills the spaces in the Cu coil are formed. On top of this, via a polyimide film with a thickness of 10 &mgr;m, a magnetic thin film that is a polyimide film containing Fe particles and that has a thickness of 20 &mgr;m is formed. This thin film inductor has a small alternating current resistance. The present invention provides a magnetic thin film that is well suited for mass production, can be manufactured easily, can be made into a thick film, has soft magnetic qualities, and is inexpensive.
    Type: Application
    Filed: May 1, 2001
    Publication date: July 11, 2002
    Inventors: Kazuo Matsuzaki, Taku Furuta, Kazumi Takagiwa, Zenchi Hayashi