Patents by Inventor Kei MINAGAWA

Kei MINAGAWA 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: 20230275506
    Abstract: A semiconductor device having a load. The semiconductor device including: an output element configure to connect to the load, the output element being switchable to operate the load; a drive circuit which outputs a drive signal for driving the output element to switch; a detection circuit which compares a state signal, indicative of an operating state of the output element, with a detection threshold, to thereby detect an abnormal level of the operating state; an abnormal level notification circuit which informs an outside of the detected abnormal level; an external terminal configured to receive an external signal for adjusting the detection threshold; and a detection threshold adjustment circuit which adjusts the detection threshold on a basis of the received external signal.
    Type: Application
    Filed: December 28, 2022
    Publication date: August 31, 2023
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Kei MINAGAWA
  • Patent number: 11594873
    Abstract: A semiconductor device includes a switching element, a control circuit, and a first and second temperature detectors. The control circuit controls the switching element and have an overcurrent detection circuit for the switching element. The first temperature detector detects the temperature of the switching element and the second temperature detector detects the temperature of the control circuit. The control circuit includes a reference correction circuit for correcting an overcurrent reference value of the overcurrent detection circuit on the basis of a first detection value and a second detection value detected by the first and second temperature detectors and outputting a corrected overcurrent reference value.
    Type: Grant
    Filed: February 25, 2021
    Date of Patent: February 28, 2023
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Kei Minagawa
  • Patent number: 11575371
    Abstract: A semiconductor device including a plurality of power modules each of which includes a power semiconductor switching element that has a temperature detection diode, and a drive circuit that has an output circuit for switching on and off the power semiconductor switching element, and that outputs a warning signal for calling attention if the value of the forward voltage of the temperature detection diode becomes equal to or smaller than a first reference voltage value, and that outputs a protection operation signal for stopping the on/off operation of the power semiconductor switching element if the value of the forward voltage becomes equal to or smaller than a second reference voltage value smaller than the first reference voltage value. The semiconductor device outputs the logical sum of the warning signals of the individual power modules as an external warning signal.
    Type: Grant
    Filed: July 28, 2021
    Date of Patent: February 7, 2023
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Kei Minagawa
  • Publication number: 20220069815
    Abstract: A semiconductor device including a plurality of power modules each of which includes a power semiconductor switching element that has a temperature detection diode, and a drive circuit that has an output circuit for switching on and off the power semiconductor switching element, and that outputs a warning signal for calling attention if the value of the forward voltage of the temperature detection diode becomes equal to or smaller than a first reference voltage value, and that outputs a protection operation signal for stopping the on/off operation of the power semiconductor switching element if the value of the forward voltage becomes equal to or smaller than a second reference voltage value smaller than the first reference voltage value. The semiconductor device outputs the logical sum of the warning signals of the individual power modules as an external warning signal.
    Type: Application
    Filed: July 28, 2021
    Publication date: March 3, 2022
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Kei MINAGAWA
  • Publication number: 20210296881
    Abstract: A semiconductor device includes a switching element, a control circuit, and a first and second temperature detectors. The control circuit controls the switching element and have an overcurrent detection circuit for the switching element. The first temperature detector detects the temperature of the switching element and the second temperature detector detects the temperature of the control circuit. The control circuit includes a reference correction circuit for correcting an overcurrent reference value of the overcurrent detection circuit on the basis of a first detection value and a second detection value detected by the first and second temperature detectors and outputting a corrected overcurrent reference value.
    Type: Application
    Filed: February 25, 2021
    Publication date: September 23, 2021
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Kei MINAGAWA
  • Patent number: 10910823
    Abstract: A semiconductor device protection circuit for a semiconductor device driving circuit that switches a voltage-controlled semiconductor device ON and OFF includes a current detection circuit that detects current flowing through the semiconductor device and generates and outputs a current detection voltage representing the detected current; an overcurrent detection circuit that compares the current detection voltage to a variable overcurrent detection threshold voltage so as to detect for overcurrent flowing through the semiconductor device; a protection circuit that, when the overcurrent detection circuit detects overcurrent, controls the ON/OFF switching of the semiconductor device so as to prevent thermal breakdown of the semiconductor device; and a gate voltage detection circuit that, in accordance with a gate voltage of the semiconductor device, selectively sets the overcurrent detection threshold voltage to either a first threshold voltage or a second threshold voltage that is lower than the first threshol
    Type: Grant
    Filed: March 6, 2018
    Date of Patent: February 2, 2021
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Kei Minagawa
  • Patent number: 10770888
    Abstract: The overcurrent protection device includes: a current detection unit configured to detect, as a sense voltage, a sense current flowing through a current sense terminal of a voltage-controlled semiconductor device; an overcurrent detection unit configured to compare the sense voltage detected by the current detection unit with an overcurrent threshold value to output an overcurrent detection signal; a mode determination unit configured to determine whether a superposition mode in which a transient sense voltage is superimposed on the sense voltage or a normal mode in which the transient sense voltage is not superimposed on the sense voltage; and a timing adjustment unit configured to adjust a detection start timing of the overcurrent detection signal based on a result of determination by the mode determination unit.
    Type: Grant
    Filed: January 22, 2018
    Date of Patent: September 8, 2020
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Kei Minagawa
  • Publication number: 20180316182
    Abstract: A semiconductor device protection circuit for a semiconductor device driving circuit that switches a voltage-controlled semiconductor device ON and OFF includes a current detection circuit that detects current flowing through the semiconductor device and generates and outputs a current detection voltage representing the detected current; an overcurrent detection circuit that compares the current detection voltage to a variable overcurrent detection threshold voltage so as to detect for overcurrent flowing through the semiconductor device; a protection circuit that, when the overcurrent detection circuit detects overcurrent, controls the ON/OFF switching of the semiconductor device so as to prevent thermal breakdown of the semiconductor device; and a gate voltage detection circuit that, in accordance with a gate voltage of the semiconductor device, selectively sets the overcurrent detection threshold voltage to either a first threshold voltage or a second threshold voltage that is lower than the first threshol
    Type: Application
    Filed: March 6, 2018
    Publication date: November 1, 2018
    Applicant: Fuji Electric Co., Ltd.
    Inventor: Kei MINAGAWA
  • Patent number: 10020297
    Abstract: Control ICs for controlling IGBTs include overheat detection comparators that determine an overheated state of the case, in addition to overheat detection comparators that determine an overheated state of chips of the IGBTs. Outputs of the overheat detection comparators are input into an AND circuit, and when all of the overheat detection comparators determine the overheated state of the case, the AND circuit outputs a protection operation signal of high level, and an alarm output circuit outputs an alarm signal. The overheated state of the chips and the overheated state of the case are detected on the basis of chip temperatures measured by temperature detection diodes which are provided with the IGBTs respectively, and therefore a temperature detection IC for case overheat protection is unnecessary, and detection accuracy of the case overheat improves.
    Type: Grant
    Filed: September 1, 2016
    Date of Patent: July 10, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Kei Minagawa
  • Publication number: 20180145503
    Abstract: The overcurrent protection device includes: a current detection unit configured to detect, as a sense voltage, a sense current flowing through a current sense terminal of a voltage-controlled semiconductor device; an overcurrent detection unit configured to compare the sense voltage detected by the current detection unit with an overcurrent threshold value to output an overcurrent detection signal; a mode determination unit configured to determine whether a superposition mode in which a transient sense voltage is superimposed on the sense voltage or a normal mode in which the transient sense voltage is not superimposed on the sense voltage; and a timing adjustment unit configured to adjust a detection start timing of the overcurrent detection signal based on a result of determination by the mode determination unit.
    Type: Application
    Filed: January 22, 2018
    Publication date: May 24, 2018
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Kei MINAGAWA
  • Publication number: 20160372454
    Abstract: Control ICs for controlling IGBTs include overheat detection comparators that determine an overheated state of the case, in addition to overheat detection comparators that determine an overheated state of chips of the IGBTs. Outputs of the overheat detection comparators are input into an AND circuit, and when all of the overheat detection comparators determine the overheated state of the case, the AND circuit outputs a protection operation signal of high level, and an alarm output circuit outputs an alarm signal. The overheated state of the chips and the overheated state of the case are detected on the basis of chip temperatures measured by temperature detection diodes which are provided with the IGBTs respectively, and therefore a temperature detection IC for case overheat protection is unnecessary, and detection accuracy of the case overheat improves.
    Type: Application
    Filed: September 1, 2016
    Publication date: December 22, 2016
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventor: Kei MINAGAWA
  • Patent number: 9476916
    Abstract: An overcurrent detection apparatus includes a sense emitter current detection unit that detects a sense emitter current output from a sense emitter of an IGBT as a sense emitter voltage, and a comparison unit that detects an overcurrent by comparing the sense emitter voltage detected by the sense emitter current detection unit with a threshold voltage. The overcurrent detection apparatus also includes a correction current detection unit that detects a correction current corresponding to a current flowing between a gate and the sense emitter of the IGBT as a corrected voltage; and a voltage correction unit that calculates a sense emitter corrected voltage by subtracting the correction voltage detected by the corrected current detection unit from the sense emitter voltage detected by the sense emitter current detection unit, and supplies the sense emitter corrected voltage to the comparison unit.
    Type: Grant
    Filed: September 5, 2014
    Date of Patent: October 25, 2016
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventor: Kei Minagawa
  • Publication number: 20140375333
    Abstract: An overcurrent detection apparatus includes a sense emitter current detection unit that detects a sense emitter current output from a sense emitter of an IGBT as a sense emitter voltage, and a comparison unit that detects an overcurrent by comparing the sense emitter voltage detected by the sense emitter current detection unit with a threshold voltage. The overcurrent detection apparatus also includes a correction current detection unit that detects a correction current corresponding to a current flowing between a gate and the sense emitter of the IGBT as a corrected voltage; and a voltage correction unit that calculates a sense emitter corrected voltage by subtracting the correction voltage detected by the corrected current detection unit from the sense emitter voltage detected by the sense emitter current detection unit, and supplies the sense emitter corrected voltage to the comparison unit.
    Type: Application
    Filed: September 5, 2014
    Publication date: December 25, 2014
    Inventor: Kei MINAGAWA