Patents by Inventor Naoki Kumagai
Naoki Kumagai 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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Publication number: 20060027863Abstract: A lateral MOSFET and a method of forming thereof includes a p-type semiconductor substrate, a first n-type well in the surface portion of the semiconductor substrate, an n+-type drain region in the first n-type well, a p-type well in the first n-type well, an n+-type source region in the p-type well, a gate oxide film on the portion of the p-type well between the n+-type source region and the first n-type well, a gate electrode on the gate oxide film, and a second n-type well containing the p-type well therein to increase the n-type impurity concentration in the vicinity of the junction between the p-type well and the first n-type well beneath the gate and to increase the impurity amount and the thickness of the n-type semiconductor region beneath the p-type well. The first and second n-type wells can be overlapping or formed continuous or contiguous with each other. The lateral MOSFET exhibits a high punch-through breakdown voltage suitable for a high-side switch.Type: ApplicationFiled: August 3, 2005Publication date: February 9, 2006Applicant: Fuji Electric Device Technology Co., Ltd.Inventors: Naoki Kumagai, Yuuichi Harada, Hiroshi Kanemaru, Yoshihiro Ikura, Ryuu Saitou
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Publication number: 20060022265Abstract: A semiconductor device realizes a high electrostatic discharge withstanding capability and a high surge withstanding capability within the narrow chip area of a lateral MOSFET used in integrated intelligent switching devices, double-integration-type signal input and transfer IC's, and combined power IC's. The semiconductor device includes a vertical bipolar transistor in which a base is electrically connected to an emitter and a collector, and a lateral MOSFET including a drain electrode connected to a surface electrode. The vertical bipolar transistor absorbs electrostatic discharge or surge energy when a high electrostatic discharge voltage or a high surge voltage is applied and limits the electrostatic discharge voltage or the surge voltage to be lower than the breakdown voltage of the lateral MOSFET.Type: ApplicationFiled: September 26, 2005Publication date: February 2, 2006Applicant: Fuji Electric Co., Ltd.Inventors: Kazuhiko Yoshida, Takeshi Ichimura, Tatsuhiko Fujihira, Naoki Kumagai
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Patent number: 6977425Abstract: A semiconductor device realizes a high electrostatic discharge withstanding capability and a high surge withstanding capability within the narrow chip area of a lateral MOSFET used in integrated intelligent switching devices, double-integration-type signal input and transfer IC's, and combined power IC's. The semiconductor device includes a vertical bipolar transistor in which a base is electrically connected to an emitter and a collector, and a lateral MOSFET including a drain electrode connected to a surface electrode. The vertical bipolar transistor absorbs electrostatic discharge or surge energy when a high electrostatic discharge voltage or a high surge voltage is applied and limits the electrostatic discharge voltage or the surge voltage to be lower than the breakdown voltage of the lateral MOSFET.Type: GrantFiled: May 21, 2003Date of Patent: December 20, 2005Assignee: Fuji Electric Co., Ltd.Inventors: Kazuhiko Yoshida, Takeshi Ichimura, Tatsuhiko Fujihira, Naoki Kumagai
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Patent number: 6934139Abstract: An intelligent power module includes semiconductor switching devices, drive circuits, a variety of detecting circuits and warning circuits for detecting a fatal abnormal condition and a precursory abnormal condition thereof in the switching devices, the drive circuits and so forth, abnormal condition detecting logic devices and drive circuits for protecting the switching devices when the detecting circuits and the warning circuits detect the abnormal condition, and control circuits and a transmission circuit for outputting a signal based on detection of the abnormal condition. The transmission circuit has an output terminal for outputting alarm signals when the fatal abnormal condition is detected, and an output terminal for outputting abnormality factor discrimination signals indicating abnormality factors contributing to the fatal abnormal condition and the precursory abnormal condition.Type: GrantFiled: May 1, 2001Date of Patent: August 23, 2005Assignee: Fuji Electric Device Technology Co., Ltd.Inventors: Naoki Kumagai, Kazunori Oyabe, Naotaka Matsuda
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Publication number: 20050145975Abstract: A semiconductor device is configured to prevent destruction of elements and/or miss-operation of the circuit by parasitic effects produced by parasitic transistors when a MOSFET of a bridge circuit is formed on a single chip. A Schottky junction is formed by providing an anode electrode in an n well region where a source region, a drain region, and a p well region of a lateral MOSFET. A Schottky barrier diode constituting a majority carrier device is connected in parallel with a PN junction capable of being forward-biased so that the PN junction is not forward-biased so that minority carriers are not generated, and thereby suppressing parasitic effects.Type: ApplicationFiled: February 10, 2005Publication date: July 7, 2005Applicant: Fuji Electric Co., Ltd.Inventors: Naoki Kumagai, Yuuichi Harada, Shinichi Jimbo, Yoshihiro Ikura, Tatsuhiko Fujihira, Kazuhiko Yoshida
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Patent number: 6870223Abstract: A semiconductor device is configured to prevent destruction of elements and/or miss-operation of the circuit by parasitic effects produced by parasitic transistors when a MOSFET of a bridge circuit is formed on a single chip. A Schottky junction is formed by providing an anode electrode in an n well region where a source region, a drain region, and a p well region of a lateral MOSFET. A Schottky barrier diode constituting a majority carrier device is connected in parallel with a PN junction capable of being forward-biased so that the PN junction is not forward-biased so that minority carriers are not generated, and thereby suppressing parasitic effects.Type: GrantFiled: November 21, 2002Date of Patent: March 22, 2005Assignee: Fuji Electric Co., Ltd.Inventors: Naoki Kumagai, Yuuichi Harada, Shinichi Jimbo, Yoshihiro Ikura, Tatsuhiko Fujihira, Kazuhiko Yoshida
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Publication number: 20040026728Abstract: A semiconductor device realizes a high electrostatic discharge withstanding capability and a high surge withstanding capability within the narrow chip area of a lateral MOSFET used in integrated intelligent switching devices, double-integration-type signal input and transfer IC's, and combined power IC's. The semiconductor device includes a vertical bipolar transistor in which a base is electrically connected to an emitter and a collector, and a lateral MOSFET including a drain electrode connected to a surface electrode. The vertical bipolar transistor absorbs electrostatic discharge or surge energy when a high electrostatic discharge voltage or a high surge voltage is applied and limits the electrostatic discharge voltage or the surge voltage to be lower than the breakdown voltage of the lateral MOSFET.Type: ApplicationFiled: May 21, 2003Publication date: February 12, 2004Inventors: Kazuhiko Yoshida, Takeshi Ichimura, Tatsuhiko Fujihira, Naoki Kumagai
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Publication number: 20030127687Abstract: A semiconductor device is configured to prevent destruction of elements and/or miss-operation of the circuit by parasitic effects produced by parasitic transistors when a MOSFET of a bridge circuit is formed on a single chip. A Schottky junction is formed by providing an anode electrode in an n well region where a source region, a drain region, and a p well region of a lateral MOSFET. A Schottky barrier diode constituting a majority carrier device is connected in parallel with a PN junction capable of being forward-biased so that the PN junction is not forward-biased so that minority carriers are not generated, and thereby suppressing parasitic effects.Type: ApplicationFiled: November 21, 2002Publication date: July 10, 2003Inventors: Naoki Kumagai, Yuuichi Harada, Shinichi Jimbo, Yoshihiro Ikura, Tatsuhiko Fujihira, Kazuhiko Yoshida
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Patent number: 6570413Abstract: A drive circuit drives a voltage-controlled semiconductor switching device with a control terminal. The drive circuit includes a device for supplying a current to the control terminal based on an input of an ON signal, and a device for removing a current from the control terminal of the voltage-controlled semiconductor switching device based on an input of an OFF signal. The current-supplying device includes a voltage-controlled transistor having a gate electrode and a drain electrode connected to the control terminal, and a capacitor connected between the gate and drain electrodes of the voltage-controlled transistor. It is possible to reduce turn-on losses during the turn-on time of the switching device while reducing noises generated thereat.Type: GrantFiled: September 14, 2000Date of Patent: May 27, 2003Assignee: Fuji Electric Co., Ltd.Inventors: Naoki Kumagai, Hiroyuki Kawakami
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Patent number: 6501321Abstract: A level shift circuit applies an on signal 25 and an off signal 26 each consisting of pulses, to high-voltage MOSFETs 1, 2, respectively, having their source connected to a common potential COM to induce a voltage drop in load resistors 3, 4 in order to set or reset a RS latch 15 to turn on or off an IGBT 17 on an upper arm of a PWM inverter bridge circuit having a varying emitter potential, a circuit free from a long time delay prevents an increase dV/dt in potential of an AC output terminal OUT that results in charging of a capacity between a source and a drain of each of the high-voltage MOSFETs 1, 2, whereby the charge current induces a voltage drop in the resistors 3, 4 to cause the RS latch to malfunction. NOT circuits 8, 11 and a NOR circuit 13 transmit a regular on signal, while NOT circuits 9, 12 and a NOR circuit 14 transmit a regular off signal.Type: GrantFiled: October 5, 2001Date of Patent: December 31, 2002Assignee: Fuji Electric Co., Ltd.Inventor: Naoki Kumagai
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Patent number: 6501814Abstract: A dry radioactive substance storage facility stores spent fuel assemblies from nuclear power plants. The facility comprises a structure having a storage room storing storage tubes containing spent fuel assemblies. An air inlet duct defining an air inlet passage through which air is supplied into the storage room and a stack defining an air discharge passage through which air from the storage room is discharged outside are connected to the storage room. Radiation shielding members are disposed on the side of the air inlet duct and on the side of the stack, respectively, in the storage room to intercept radiation propagating toward the air inlet passage and the air discharge passage.Type: GrantFiled: September 25, 2001Date of Patent: December 31, 2002Assignee: Hitachi, Ltd.Inventors: Masashi Shimizu, Koichi Maki, Keiichiro Shibata, Masashi Oda, Naoki Kumagai, Hidetoshi Kanai
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Publication number: 20020196890Abstract: A dry radioactive substance storage facility stores spent fuel assemblies from nuclear power plants. The facility comprises a structure having a storage room storing storage tubes containing spent fuel assemblies. An air inlet duct defining an air inlet passage through which air is supplied into the storage room and an stack defining an air discharge passage through which air from the storage room is discharged outside are connected to the storage room. Radiation shielding members are disposed on the side of the air inlet duct and on the side of the stack, respectively, in the storage room to intercept radiation propagating toward the air inlet passage and the air discharge passage.Type: ApplicationFiled: September 25, 2001Publication date: December 26, 2002Applicant: Hitachi, Ltd.Inventors: Masashi Shimizu, Koichi Maki, Keiichiro Shibata, Masashi Oda, Naoki Kumagai, Hidetoshi Kanai
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Patent number: 6430248Abstract: A dry radioactive substance storage facility stores spent fuel assemblies from nuclear power plants. The facility comprises a structure having a storage room storing storage tubes containing spent fuel assemblies. An air inlet duct defining an air inlet passage through which air is supplied into the storage room and an stack defining an air discharged passage through which air from the storage room is discharge outside are connected to the storage room. Radiation shielding members are disposed on the side of the air inlet duct and on the side of the stack, respectively, in the storage room to intercept radiation propagating toward the air inlet passage and the air discharge passage.Type: GrantFiled: December 21, 1999Date of Patent: August 6, 2002Assignee: Hitachi, Ltd.Inventors: Masashi Shimizu, Koichi Maki, Keiichiro Shibata, Masashi Oda, Naoki Kumagai, Hidetoshi Kanai
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Publication number: 20020039269Abstract: An intelligent power module includes semiconductor switching devices, drive circuits, a variety of detecting circuits and warning circuits for detecting a fatal abnormal condition and a precursory abnormal condition thereof in the switching devices, the drive circuits and so forth, abnormal condition detecting logic devices and drive circuits for protecting the switching devices when the detecting circuits and the warning circuits detect the abnormal condition, and control circuits and a transmission circuit for outputting a signal based on detection of the abnormal condition. The transmission circuit has an output terminal for outputting alarm signals when the fatal abnormal condition is detected, and an output terminal for outputting abnormality factor discrimination signals indicating abnormality factors contributing to the fatal abnormal condition and the precursory abnormal condition.Type: ApplicationFiled: May 1, 2001Publication date: April 4, 2002Inventors: Naoki Kumagai, Kazunori Oyabe
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Publication number: 20020014905Abstract: A level shift circuit applies an on signal 25 and an off signal 26 each consisting of pulses, to high-voltage MOSFETs 1, 2, respectively, having their source connected to a common potential COM to induce a voltage drop in load resistors 3, 4 in order to set or reset a RS latch 15 to turn on or off an IGBT 17 on an upper arm of a PWM inverter bridge circuit having a varying emitter potential, a circuit free from a long time delay prevents an increase dV/dt in potential of an AC output terminal OUT that results in charging of a capacity between a source and a drain of each of the high-voltage MOSFETs 1, 2, whereby the charge current induces a voltage drop in the resistors 3, 4 to cause the RS latch to malfunction. NOT circuits 8, 11 and a NOR circuit 13 transmit a regular on signal, while NOT circuits 9, 12 and a NOR circuit 14 transmit a regular off signal.Type: ApplicationFiled: October 5, 2001Publication date: February 7, 2002Applicant: Fuji Electric, Co., Ltd.Inventor: Naoki Kumagai
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Patent number: 6326831Abstract: A level shift circuit applies an on signal 25 and an off signal 26 each consisting of pulses, to high-voltage MOSFETs 1, 2, respectively, having their source connected to a common potential COM to induce a voltage drop in load resistors 3, 4 in order to set or reset a RS latch 15 to turn on or off an IGBT 17 on an upper arm of a PWM inverter bridge circuit having a varying emitter potential, a circuit free from a long time delay prevents an increase dV/dt in potential of an AC output terminal OUT that results in charging of a capacity between a source and a drain of each of the high-voltage MOSFETs 1, 2, whereby the charge current induces a voltage drop in the resistors 3, 4 to cause the RS latch to malfunction. NOT circuits 8, 11 and a NOR circuit 13 transmit a regular on signal, while NOT circuits 9, 12 and a NOR circuit 14 transmit a regular off signal.Type: GrantFiled: March 2, 2000Date of Patent: December 4, 2001Assignee: Fuji Electric Co., Ltd.Inventor: Naoki Kumagai
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Patent number: 6323539Abstract: A high voltage integrated circuit is provided that includes a first region of first conductivity type; a second region of second conductivity type formed in a first major surface of the first region; a third region of first conductivity type formed in a selected area of a surface of the second region; first source region and first drain region of the first conductivity type formed in the second region, apart from the third region; a first gate electrode formed on a surface of the second region between the first source region and first drain region, through an insulating film; second source region and second drain region of second conductivity type formed in a surface of the third region; and a second gate electrode formed on a surface of the third region between the second source region and the second drain region, through an insulating film.Type: GrantFiled: August 16, 2000Date of Patent: November 27, 2001Assignee: Fuji Electric Co., Ltd.Inventors: Tatsuhiko Fujihira, Yukio Yano, Shigeyuki Obinata, Naoki Kumagai
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Patent number: 6124628Abstract: A high voltage integrated circuit is provided that includes a first region of first conductivity type; a second region of second conductivity type formed in a first major surface of the first region; a third region of first conductivity type formed in a selected area of a surface of the second region; first source region and first drain region of the first conductivity type formed in the second region, apart from the third region; a first gate electrode formed on a surface of the second region between the first source region and first drain region, through an insulating film; second source region and second drain region of second conductivity type formed in a surface of the third region; and a second gate electrode formed on a surface of the third region between the second source region and the second drain region, through an insulating film.Type: GrantFiled: April 12, 1996Date of Patent: September 26, 2000Assignee: Fuji Electric Co., Ltd.Inventors: Tatsuhiko Fujihira, Yukio Yano, Shigeyuki Obinata, Naoki Kumagai
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Patent number: 5925900Abstract: The operating characteristics of emitter-switched thyristors (1) are improved by the addition of a floating ohmic contact (14) over adjacent regions of n+ and p+ type (15,16). In a lateral device, the floating ohmic contact (14) and the adjacent regions of n+ and p+ type (15,16) are provided between the anode region (4) and the cathode region (8,9,10). The device has enhanced turn-on characteristics with a high breakdown voltage and high current density capabilities.Type: GrantFiled: April 8, 1997Date of Patent: July 20, 1999Assignee: Fuji Electric Co., Ltd.Inventors: Gehan Anil Joseph Amaratunga, Wei Chen, Naoki Kumagai
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Patent number: 5896043Abstract: A level shift circuit includes first and second operation circuits, a bias circuit, and a current control circuit. The first and second operation circuits include high-voltage transistors and low-voltage transistors connected in series. The high-voltage transistors are controlled according to a potential at the interconnection point between the low-voltage and high-voltage transistors of opposite operation circuits. The bias circuit is provided in a one-to-one correspondence with the operation circuits and connected to the low-voltage transistors in series to activate the transistors in the stationary on state and decrease currents flowing into the transistors to a stationary current. The current control circuit connects to the bias circuit in parallel to increase the currents just after the low-level transistors are turned on to a high peak current. The low-voltage transistors are turned on/off alternately in response to the state transition of an input signal.Type: GrantFiled: January 16, 1997Date of Patent: April 20, 1999Assignee: Fuji Electric Co., Ltd.Inventor: Naoki Kumagai