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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Patent number: 5844760Abstract: An insulated-gate controlled semiconductor device includes a main circuit that is controlled by an insulated gate having a gate resistor, an overload detector having the insulated gate for use in common with the main circuit, the overload detector being of the same construction as that of the main circuit, a current detector for detecting current passing through the overload detector, and a field effect transistor having a gate which responds to the voltage drop across the current detector. The main circuit is protected by lowering the voltage applied to the insulated gate through the gate resistor and through the low on-resistance of the field effect transistor while the field effect transistor is held on.Type: GrantFiled: January 7, 1993Date of Patent: December 1, 1998Assignee: Fuji Electric Co., Ltd.Inventors: Naoki Kumagai, Katsunori Ueno
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Patent number: 5744830Abstract: A semiconductor device made of a lightly doped region of a first conductivity type has a well formed of a second conductivity type. The well extends to the surface of the device. First, second and third heavily doped regions of the first conductivity type are in the surface of the well. An electrode is fixed to the first heavily doped region of the first conductivity type. The third heavily doped region of the first conductivity type adjoins the lightly doped region of the first conductivity type. The first and second heavily doped regions of the first conductivity type are spaced apart from one another so that a portion of the well extends to the surface of the device therebetween. A first gate electrode is fixed via an insulating layer to a portion of the well extending between the first and second heavily doped regions. The first and third heavily doped regions of the first conductivity type are spaced apart from one another so that a portion of the well extends therebetween.Type: GrantFiled: November 13, 1995Date of Patent: April 28, 1998Assignee: Fuji Electric Co., Ltd.Inventors: Sankaranarayanan Ekkanath-Madathil, Qin Huang, Gehan Anil Joseph Amaratunga, Naoki Kumagai
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Patent number: 5585650Abstract: High withstand voltage, low on-voltage, low turn-off loss, and high switching speed are realized in semiconductor bidirectional switches in which the potential of the substrate is floating. A switch has a p-type substrate without an electrode, and an n-layer on the substrate. At least one pair of p-well regions and at least one p-region are formed in a surface layer of the n-layer. An n.sup.+ region is formed in the p-well region, and a gate electrode is fixed via an insulation film to the p-well region. A main electrode is fixed to a part of the surface of the n.sup.+ region and the surface of a p.sup.+ contact region in the p-well region.Type: GrantFiled: August 8, 1995Date of Patent: December 17, 1996Assignee: Fuji Electric Co., Ltd.Inventor: Naoki Kumagai
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Patent number: 5477077Abstract: In diodes used with high withstand voltages, the pin-type diode has a low on-resistance, but a large switching loss. Even if a lifetime killer is introduced, the low on-resistance and the switching loss cannot be compatible since both factors are in a trade-off relation. The invention overcomes these problems by providing a semiconductor device that includes p.sup.+ -type anode layers and p.sup.+ -type floating drain layers that are connected to the anode layers by a MOSFET 20 formed on the surface of an n.sup.- -type conductivity-modulating layer. When a forward voltage is applied, holes are injected from the drain layers to create an element with a conductivity-modulated condition and realize a low on-resistance. By the time a reverse voltage is applied, the drain layers have already been separated to reduce the number of excessive carriers. Thus, the reverse recovery current is suppressed.Type: GrantFiled: April 12, 1993Date of Patent: December 19, 1995Assignee: Fuji Electric Co., Ltd.Inventors: Naoki Kumagai, Katsunori Ueno
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Patent number: 5475333Abstract: A built-in drive-power-source semiconductor device of low cost having a good switching characteristic and a decreased switching loss. In operation, a reference charge potential is applied to a charging IGBT by a first constant voltage diode thereby turning on the IGBT to charge a battery means. When the charge potential of the battery means reaches a prescribed level, a MOSFET is turned on by a second constant voltage diode, shortcircuiting the first constant voltage diode, causing the charging IGBT is turn off to eliminate overcharging of the batter means and maintain the potential of the battery means at a prescribed value.Type: GrantFiled: December 2, 1993Date of Patent: December 12, 1995Assignee: Fuji Electric Co., Ltd.Inventor: Naoki Kumagai
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Patent number: 5430323Abstract: An injection control-type Schottky barrier rectifier, including: a semiconductor region having a first conductivity type; a first diffusion region, which is formed in the semiconductor region and which has a second conductivity type, the second conductivity type being different from the first conductivity type, for forming a depletion layer in the semiconductor region when a turn-off voltage is applied to the Schottky barrier rectifier; a second diffusion region, which is formed in the semiconductor region and which has the second conductivity type, for causing conductivity modulation in the semiconductor region when a turn-on voltage is applied to the Schottky barrier rectifier; a barrier electrode which is ohmically connected with the first diffusion region and which forms a Schottky junction with the surface of the semiconductor region which is opposite to the second diffusion region with respect to the first diffusion region; a gate insulator film formed on the surface of the semiconductor region betweenType: GrantFiled: September 30, 1993Date of Patent: July 4, 1995Assignee: Fuji Electric Co., Ltd.Inventors: Tomoyuki Yamazaki, Naoki Kumagai
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Patent number: 5380190Abstract: The present invention provides a relatively compact-sized pulse combustor which efficiently reduces an undesirable explosion and combustion noise without any bulky muffler. In the pulse combustor of the invention, a compensating sound is generated in an exhaust conduit synchronously with pulsative explosion and combustion. The compensating sound has a sound pressure identical with that of a noise in the exhaust conduit but a phase opposite to that of the noise, thus effectively compensating the noise in the exhaust conduit and efficiently reducing the noise from an exhaust outlet.Type: GrantFiled: August 20, 1993Date of Patent: January 10, 1995Assignee: Paloma Kogyo Kabushiki KaishaInventor: Naoki Kumagai
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Patent number: 5374203Abstract: An edge connector (1) having metal latching devices (5) to latch and unlatch a circuit board (4) is disclosed. More particularly the latching devices (5) include a latching section (53) for latching the board (4) and an unlatching section (54) for releasing the board (4).Type: GrantFiled: January 6, 1994Date of Patent: December 20, 1994Assignee: The Whitaker CorporationInventors: Yoshio Sato, Takashi Kamono, Ryoji Nishimura, Tsutomi Nakamura, Naoki Kumagai
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Patent number: 5304802Abstract: A semiconductor device including a switching device such as a MOSFET or an IGBT, and an avalanche device for protecting the switching device by generating an avalanche current when an overvoltage is applied to the switching device. The avalanche device shares a drift layer, that is, an epitaxial layer with the switching device. With this arrangement, the avalanche voltage of the avalanche device follows changes in the withstanding voltages of the switching device due to variations in the thickness or impurity concentration of the epitaxial layer or temperature. This makes it possible to reduce the margin between the avalanche voltage of the avalanche device and the withstanding voltage of the switching device, and to positively protect the switching device from damage.Type: GrantFiled: January 5, 1993Date of Patent: April 19, 1994Assignee: Fuji Electric Co., Ltd.Inventor: Naoki Kumagai
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Patent number: 5303110Abstract: An insulated-gate controlled semiconductor device including a main circuit that is controlled by an insulated gate having a gate resistor, an overload detector having the insulated gate for use in common with the main circuit, the overload detector being of the same construction as that of the main circuit, a current detector for detecting current passing through the overload detector, and a field effect transistor having a gate which accedes to the voltage drop of the current detector the main circuit being protected by lowering the voltage applied to the insulated gate through gate resistance and on-resistance of the field effect transistor while the field effect transistor is held on.Type: GrantFiled: March 19, 1992Date of Patent: April 12, 1994Assignee: Fuji Electric Co., Ltd.Inventor: Naoki Kumagai
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Patent number: 5092959Abstract: A spray dryer device for spray drying a sample dissolved in an organic solvent is disclosed, comprising a circulation line in which an inert gas is circulated by a blower, a heater for heating the inert gas to a specified temperature, a main drying chamber provided with a spray nozzle through which the sample dissolved in the organic solvent is sprayed into the inert gas, a collector in which the powdered sample produced in the main drying chamber is collected, and a condenser in which the gaseous organic solvent is condensed and recovered. The powdered sample is obtained in this spray dryer device for spray drying organic solvents by spraying the organic solvent through the spray nozzle into the main drying chamber in which the oxygen concentration is held to a low value by the introduction of the inert gas.Type: GrantFiled: August 2, 1990Date of Patent: March 3, 1992Assignee: Yamato Scientific Co., Ltd.Inventors: Takeshi Orii, Yukio Suzuki, Tamotsu Konishi, Naoki Kumagai, Hiroaki Mori
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Patent number: 5068581Abstract: Horizontal deflection circuits are disclosed which permit high-frequency operation through use of conductivity modulation MOS FET devices. Distortion of the horizontal deflection coil voltage is avoided by inclusion of compensation means utilizing an inductance to produce delay in the increase in magnitude of current flow during reverse recovery current flow. Use of a compensation means including an inductor and diode in parallel combination provides additional benefits of oscillation suppression.Type: GrantFiled: August 27, 1990Date of Patent: November 26, 1991Assignee: Fuji Electric Co., Ltd.Inventors: Akira Nishiura, Naoki Kumagai, Yasukazu Seki
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Patent number: 5051808Abstract: A semiconductor device having the function of a conductivity-modulation type MOSFET with improved switching speed is disclosed, which device has low inductance of wirings connecting individual elements of the device. The elements forming the semiconductor device are connected by short, deposited wirings in the silicon substrate or on the silicon substrate, thereby minimizing the inductance of the wiring.Type: GrantFiled: May 29, 1990Date of Patent: September 24, 1991Assignee: Fuji Electric Co., Ltd.Inventors: Akira Saito, Naoki Kumagai
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Patent number: 4984996Abstract: An edge connector (5) for receiving an edge of a circuit board (6) is disclosed. The contacts (2) positioned in the housing (4) of the connector (5) include a resilient stand-up section (25) having a tip (25a) defining a first contact point (A) and a C-shaped section (26) having a tip (26a) defining a second contact point (C) with the circuit board (6) being received between the first and second contact points (A,C).Type: GrantFiled: July 10, 1990Date of Patent: January 15, 1991Assignee: AMP IncorporatedInventors: Tetsuya Watanabe, Yoshio Sato, Tsutomu Nakamura, Naoki Kumagai, Takashi Kamono
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Patent number: 4899029Abstract: A high-speed welding apparatus comprises a frame F along which a first conveying mechanism (20) moves a carrier member (11) having mounted thereon a holder (14) holding a connector (100) and a cable (103) to a welding station (30). A feed mechanism (30A) at the welding station (30) engages the carrier member (11) and continously feeds it at a specified speed along the welding station (30) so that a welding device (33) automatically welds electrical conductors of the cable (103) to respective electrical contacts of the connector (100). A second conveying mechanism (40) then moves the carrier member (11) away from the welding station (30) so that the welded connector and cable can be removed therefrom.Type: GrantFiled: October 25, 1988Date of Patent: February 6, 1990Assignee: AMP IncorporatedInventor: Naoki Kumagai
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Patent number: 3967739Abstract: An apparatus for supplying stacked, thin, flat articles comprising a reversing means which reverses the direction toward which the articles face by rotating the articles about one of their side edges and a clearance making means which provides a plurality of clearance spaces between several pairs of article side edges while the articles are being reversed. The actuating position of the clearance making means is movably adjustable relative to the reversing means.Type: GrantFiled: December 13, 1974Date of Patent: July 6, 1976Assignee: Itogihan Company, Ltd.Inventor: Naoki Kumagai
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Patent number: 3955686Abstract: An apparatus for supplying thin, flat articles has a reversing means for reversing the articles. The reversing means includes a bottom surface supporting part and an edge supporting part which is perpendicular to the bottom surface supporting part. The apparatus also has a conveyer means by which the reversed articles are received and fed. The edge supporting part has at least one fixed member which is fixed to the bottom surface supporting part and at least one sliding member which is slidably associated with the fixed member so that the length of the edge supporting part can be changed.Type: GrantFiled: March 25, 1975Date of Patent: May 11, 1976Assignee: Itogihan Company, Ltd.Inventor: Naoki Kumagai