Patents by Inventor Akira Nakamori
Akira Nakamori 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: 11333694Abstract: With regard to an instrument wherein a plurality of phase operations are carried out, the type of failure or the phase in which the failure has occurred is determined and, in accordance with the result of the determination, an alarm signal is generated. Provided that the failure details and the phase in which the failure has occurred can be determined from the generated alarm signal, it is possible, using a configuration wherein an alarm signal having a pulse number corresponding to the phase in which a failure has occurred is generated, or a configuration wherein an alarm signal having a pulse width corresponding to the phase in which a failure has occurred is generated, to determine the type of failure that has occurred and the phase in which the failure has occurred from the pulse number and pulse width.Type: GrantFiled: July 11, 2014Date of Patent: May 17, 2022Assignee: FUJI ELECTRIC CO., LTD.Inventors: Takahiro Mori, Akira Nakamori
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Publication number: 20220116032Abstract: A switching control circuit configured to control a switching device. The switching control circuit includes a detection circuit configured to detect whether a current flowing through the switching device is in an overcurrent state, a first signal output circuit configured to output a first signal indicating whether a time period of the overcurrent state is longer than a first time period, and a driving circuit. The driving circuit turns on the switching device based on a first input signal. The driving circuit turns off the switching device through a first switch based on a second input signal when the time period of the overcurrent state is shorter than the first time period, and through a second switch, having a greater on-resistance than the first switch, based on the second input signal and the first signal when the time period of the overcurrent state is longer than the first time period.Type: ApplicationFiled: December 22, 2021Publication date: April 14, 2022Applicant: FUJI ELECTRIC CO., LTD.Inventor: Akira NAKAMORI
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Publication number: 20210288571Abstract: A power conversion device including a semiconductor switching element having a control electrode terminal and two main electrode terminals and configured to control a current flowing between the two main electrodes by a drive signal applied to the control electrode terminal; and a drive circuit configured to generate the drive signal in synchronization with an input signal and to turn on/off the semiconductor switching element by the drive signal. The drive circuit is configured to detect the current flowing between the two main electrode terminals of the semiconductor switching element at a timing at which the semiconductor switching element is turned off, and to adjust a drive capacity.Type: ApplicationFiled: May 27, 2021Publication date: September 16, 2021Applicant: FUJI ELECTRIC CO., LTD.Inventor: Akira NAKAMORI
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Patent number: 10725087Abstract: To provide a semiconductor integrated device capable of a gate screening test with no need for any additional circuit and without adding any gate screening terminal. The semiconductor integrated device includes a gate drive unit configured to drive the gate of a voltage controlled semiconductor element and a regulator configured to supply a gate drive voltage to the gate drive unit. The regulator includes an external connection terminal capable of receiving a gate screening voltage for the voltage controlled semiconductor element in a gate screening test.Type: GrantFiled: April 23, 2018Date of Patent: July 28, 2020Assignee: FUJI ELECTRIC CO., LTD.Inventors: Takahiro Mori, Hitoshi Sumida, Masahiro Sasaki, Akira Nakamori, Masaru Saito, Wataru Tomita, Osamu Sasaki
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Patent number: 10700594Abstract: A power conversion device includes a power semiconductor switching device and a drive circuit. The power semiconductor switching device is configured to supply constant power to a load by switching and to be turned on and off by a control signal from an external control circuit. The drive circuit is configured to detect an operating temperature of the power semiconductor switching device and drive the power semiconductor switching device according to a result of the detection. The drive circuit includes a temperature detecting unit configured to receive the control signal from the external control circuit and detect the operating temperature of the power semiconductor switching device at timings according to the control signal.Type: GrantFiled: October 30, 2018Date of Patent: June 30, 2020Assignee: FUJI ELECTRIC CO., LTD.Inventor: Akira Nakamori
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Patent number: 10680509Abstract: A current detection device for a power semiconductor element includes an operational amplifier that fixes an emitter terminal of a sense IGBT to a voltage equal to or smaller than 1 volt of a reference voltage supply, and a current-voltage converter configured to flow in a resistor a current that is greater than and proportional to a current that flows into the operational amplifier from the sense IGBT. The current-voltage converter includes an NMOS transistor that operates with reference to an electric potential of a ground and a resistor provided at a high side of the NMOS transistor, in order to operate from the electric potential of the ground.Type: GrantFiled: June 30, 2016Date of Patent: June 9, 2020Assignee: FUJI ELECTRIC CO., LTD.Inventor: Akira Nakamori
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Patent number: 10574225Abstract: Provided is a driving circuit for driving a switching element in accordance with an input signal. The driving circuit includes a driving unit connected to a control terminal of the switching element, where the driving unit is configured to switch, in accordance with the input signal, which one of a source current and a sink current is to be fed to the control terminal of the switching element, a first limiter configured to operate with a predetermined time constant and to limit a control voltage at the control terminal of the switching element to a first reference voltage when overcurrent is detected for a collector current of the switching element, and a second limiter configured to, when the overcurrent is detected, start lowering the control voltage earlier than an operation start timing of the first limiter that is determined by the time constant.Type: GrantFiled: February 27, 2017Date of Patent: February 25, 2020Assignee: FUJI ELECTRIC CO., LTD.Inventor: Akira Nakamori
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Publication number: 20190190369Abstract: A power conversion device includes a power semiconductor switching device and a drive circuit. The power semiconductor switching device is configured to supply constant power to a load by switching and to be turned on and off by a control signal from an external control circuit. The drive circuit is configured to detect an operating temperature of the power semiconductor switching device and drive the power semiconductor switching device according to a result of the detection. The drive circuit includes a temperature detecting unit configured to receive the control signal from the external control circuit and detect the operating temperature of the power semiconductor switching device at timings according to the control signal.Type: ApplicationFiled: October 30, 2018Publication date: June 20, 2019Applicant: Fuji Electric Co., LTD.Inventor: Akira Nakamori
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Publication number: 20180372791Abstract: To provide a semiconductor integrated device capable of a gate screening test with no need for any additional circuit and without adding any gate screening terminal. The semiconductor integrated device includes a gate drive unit configured to drive the gate of a voltage controlled semiconductor element and a regulator configured to supply a gate drive voltage to the gate drive unit. The regulator includes an external connection terminal capable of receiving a gate screening voltage for the voltage controlled semiconductor element in a gate screening test.Type: ApplicationFiled: April 23, 2018Publication date: December 27, 2018Applicant: FUJI ELECTRIC CO., LTD.Inventors: Takahiro MORI, Hitoshi SUMIDA, Masahiro SASAKI, Akira NAKAMORI, Masaru SAITO, Wataru TOMITA, Osamu SASAKI
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Patent number: 10164626Abstract: A semiconductor device including a semiconductor switch circuit and a drive circuit. The semiconductor switch circuit includes a semiconductor switch and a temperature sensor for detecting a temperature in a periphery of the semiconductor switch. The drive circuit includes an overheating protection unit configured to, upon determining that the detected temperature of the semiconductor switch reaches an overheating protection temperature, perform overheating protection of the semiconductor switch and issue an overheating protection alarm signal. The drive circuit also includes an advance warning control unit configured to set a threshold temperature that is lower than the overheating protection temperature, and upon determining that the detected temperature reaches the threshold temperature, to output an advance warning signal before the overheating protection becomes operational.Type: GrantFiled: November 29, 2016Date of Patent: December 25, 2018Assignee: FUJI ELECTRIC CO., LTD.Inventor: Akira Nakamori
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Patent number: 10141834Abstract: To provide a multi-phase power conversion device control circuit capable of preventing switching elements and driver circuits of a multi-phase power conversion device from being damaged even when arm short circuits have occurred to a plurality of phases simultaneously. The control circuit includes: a current detection unit configured to detect a current flowing through the switching element as a voltage value; an overcurrent detection unit configured to, when a voltage value detected by the current detection unit is higher than a first reference voltage, output an individual overcurrent detection signal Scu; and an overcurrent state control unit configured to, when overcurrent state is detected at the current detection unit of each of two or more phases, output a multi-phase overcurrent signal and short-circuit the control terminal of the switching element to an emitter terminal thereof.Type: GrantFiled: August 29, 2017Date of Patent: November 27, 2018Assignee: FUJI ELECTRIC CO., LTDInventor: Akira Nakamori
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Publication number: 20170358982Abstract: To provide a multi-phase power conversion device control circuit capable of preventing switching elements and driver circuits of a multi-phase power conversion device from being damaged even when arm short circuits have occurred to a plurality of phases simultaneously. The control circuit includes: a current detection unit configured to detect a current flowing through the switching element as a voltage value; an overcurrent detection unit configured to, when a voltage value detected by the current detection unit is higher than a first reference voltage, output an individual overcurrent detection signal Scu; and an overcurrent state control unit configured to, when overcurrent state is detected at the current detection unit of each of two or more phases, output a multi-phase overcurrent signal and short-circuit the control terminal of the switching element to an emitter terminal thereof.Type: ApplicationFiled: August 29, 2017Publication date: December 14, 2017Applicant: FUJI ELECTRIC CO., LTD.Inventor: Akira NAKAMORI
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Publication number: 20170170820Abstract: Provided is a driving circuit for driving a switching element in accordance with an input signal. The driving circuit includes a driving unit connected to a control terminal of the switching element, where the driving unit is configured to switch, in accordance with the input signal, which one of a source current and a sink current is to be fed to the control terminal of the switching element, a first limiter configured to operate with a predetermined time constant and to limit a control voltage at the control terminal of the switching element to a first reference voltage when overcurrent is detected for a collector current of the switching element, and a second limiter configured to, when the overcurrent is detected, start lowering the control voltage earlier than an operation start timing of the first limiter that is determined by the time constant.Type: ApplicationFiled: February 27, 2017Publication date: June 15, 2017Inventor: Akira NAKAMORI
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Publication number: 20170077919Abstract: A semiconductor device including a semiconductor switch circuit and a drive circuit. The semiconductor switch circuit includes a semiconductor switch and a temperature sensor for detecting a temperature in a periphery of the semiconductor switch. The drive circuit includes an overheating protection unit configured to, upon determining that the detected temperature of the semiconductor switch reaches an overheating protection temperature, perform overheating protection of the semiconductor switch and issue an overheating protection alarm signal. The drive circuit also includes an advance warning control unit configured to set a threshold temperature that is lower than the overheating protection temperature, and upon determining that the detected temperature reaches the threshold temperature, to output an advance warning signal before the overheating protection becomes operational.Type: ApplicationFiled: November 29, 2016Publication date: March 16, 2017Applicant: FUJI ELECTRIC CO., LTD.Inventor: Akira NAKAMORI
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Publication number: 20160315531Abstract: A current detection device for a power semiconductor element includes an operational amplifier that fixes an emitter terminal of a sense IGBT to a voltage equal to or smaller than 1 volt of a reference voltage supply, and a current-voltage converter configured to flow in a resistor a current that is greater than and proportional to a current that flows into the operational amplifier from the sense IGBT. The current-voltage converter includes an NMOS transistor that operates with reference to an electric potential of a ground and a resistor provided at a high side of the NMOS transistor, in order to operate from the electric potential of the ground.Type: ApplicationFiled: June 30, 2016Publication date: October 27, 2016Applicant: FUJI ELECTRIC CO., LTD.Inventor: Akira NAKAMORI
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Patent number: 9337719Abstract: A power converter control device includes an alarm signal generation circuit which detects information necessary for a protection operation of a semiconductor element configuring a power converter, and generates and externally outputs an alarm signal with a pulse width responding to a protection factor; a temperature signal generation circuit which detects a temperature of the semiconductor element, and generates a PWM signal, correlated with the temperature, the cycle of which is different from the pulse width of the alarm signal; and an output control circuit which selects the PWM signal in normal time, and selects and externally outputs the alarm signal in place of the PWM signal when the alarm signal is generated.Type: GrantFiled: October 6, 2014Date of Patent: May 10, 2016Assignee: FUJI ELECTRIC CO., LTD.Inventors: Akira Nakamori, Satoru Motohashi
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Patent number: 9300198Abstract: A semiconductor device of the present invention determines an overheat state by comparing a forward voltage drop of a temperature sensing diode with a reference voltage, and in addition includes a series regulator circuit composed of an amplifier and resistors, that receives the forward voltage drop of a temperature sensing diode and delivers an output voltage as temperature information to an external output terminal for temperature detection of the semiconductor device. Such a device can continuously detect the temperature of the semiconductor chip.Type: GrantFiled: March 1, 2013Date of Patent: March 29, 2016Assignee: FUJI ELECTRIC CO., LTD.Inventor: Akira Nakamori
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Patent number: 9225233Abstract: Aspects of the invention include a power conversion device control device, including multiple drive circuits having an alarm signal formation circuit that sets a pulse signal having as one cycle a period. The one cycle period includes a determination period, of which a different period is set for each of plural protection circuits that detect information for carrying out a protection operation of semiconductor elements configuring a power conversion device, and a constant period, in which a condition varies with respect to the determination period, takes a protection circuit for which it is first detected that a protection operation is necessary to be a first-come first-served protection circuit, and outputs the pulse signal corresponding to the first-come first-served protection circuit as an alarm signal, wherein the alarm signal formation circuit is such that a resetting condition of the alarm signal is a condition that a protection operation stopped condition.Type: GrantFiled: September 9, 2013Date of Patent: December 29, 2015Assignee: FUJI ELECTRIC CO., LTD.Inventor: Akira Nakamori
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Publication number: 20150023076Abstract: A power converter control device includes an alarm signal generation circuit which detects information necessary for a protection operation of a semiconductor element configuring a power converter, and generates and externally outputs an alarm signal with a pulse width responding to a protection factor; a temperature signal generation circuit which detects a temperature of the semiconductor element, and generates a PWM signal, correlated with the temperature, the cycle of which is different from the pulse width of the alarm signal; and an output control circuit which selects the PWM signal in normal time, and selects and externally outputs the alarm signal in place of the PWM signal when the alarm signal is generated.Type: ApplicationFiled: October 6, 2014Publication date: January 22, 2015Inventors: Akira NAKAMORI, Satoru MOTOHASHI
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Publication number: 20140320297Abstract: With regard to an instrument wherein a plurality of phase operations are carried out, the type of failure or the phase in which the failure has occurred is determined and, in accordance with the result of the determination, an alarm signal is generated. Provided that the failure details and the phase in which the failure has occurred can be determined from the generated alarm signal, it is possible, using a configuration wherein an alarm signal having a pulse number corresponding to the phase in which a failure has occurred is generated, or a configuration wherein an alarm signal having a pulse width corresponding to the phase in which a failure has occurred is generated, to determine the type of failure that has occurred and the phase in which the failure has occurred from the pulse number and pulse width.Type: ApplicationFiled: July 11, 2014Publication date: October 30, 2014Inventors: Takahiro MORI, Akira NAKAMORI