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).
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Patent number: 11594873Abstract: 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: GrantFiled: February 25, 2021Date of Patent: February 28, 2023Assignee: FUJI ELECTRIC CO., LTD.Inventor: Kei Minagawa
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Patent number: 11575371Abstract: 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: GrantFiled: July 28, 2021Date of Patent: February 7, 2023Assignee: FUJI ELECTRIC CO., LTD.Inventor: Kei Minagawa
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Publication number: 20220069815Abstract: 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: ApplicationFiled: July 28, 2021Publication date: March 3, 2022Applicant: FUJI ELECTRIC CO., LTD.Inventor: Kei MINAGAWA
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Publication number: 20210296881Abstract: 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: ApplicationFiled: February 25, 2021Publication date: September 23, 2021Applicant: FUJI ELECTRIC CO., LTD.Inventor: Kei MINAGAWA
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Patent number: 10910823Abstract: 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 thresholType: GrantFiled: March 6, 2018Date of Patent: February 2, 2021Assignee: FUJI ELECTRIC CO., LTD.Inventor: Kei Minagawa
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Patent number: 10770888Abstract: 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: GrantFiled: January 22, 2018Date of Patent: September 8, 2020Assignee: FUJI ELECTRIC CO., LTD.Inventor: Kei Minagawa
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Publication number: 20180316182Abstract: 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 thresholType: ApplicationFiled: March 6, 2018Publication date: November 1, 2018Applicant: Fuji Electric Co., Ltd.Inventor: Kei MINAGAWA
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Patent number: 10020297Abstract: 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: GrantFiled: September 1, 2016Date of Patent: July 10, 2018Assignee: FUJI ELECTRIC CO., LTD.Inventor: Kei Minagawa
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Publication number: 20180145503Abstract: 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: ApplicationFiled: January 22, 2018Publication date: May 24, 2018Applicant: FUJI ELECTRIC CO., LTD.Inventor: Kei MINAGAWA
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Publication number: 20160372454Abstract: 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: ApplicationFiled: September 1, 2016Publication date: December 22, 2016Applicant: FUJI ELECTRIC CO., LTD.Inventor: Kei MINAGAWA
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Patent number: 9476916Abstract: 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: GrantFiled: September 5, 2014Date of Patent: October 25, 2016Assignee: FUJI ELECTRIC CO., LTD.Inventor: Kei Minagawa
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Publication number: 20140375333Abstract: 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: ApplicationFiled: September 5, 2014Publication date: December 25, 2014Inventor: Kei MINAGAWA