Patents by Inventor Naoki Maru
Naoki Maru 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: 8928363Abstract: The dead time is secured stably in a semiconductor drive circuit for switching devices using a wide band gap semiconductor. The drain terminal of the switching device of an upper arm is connected to the positive terminal of a first power supply, the source terminal of the switching device of a lower arm is connected to the negative terminal of the first power supply, and the source terminal of the switching device of the upper arm is connected with the drain terminal of the switching device of the lower arm. A gate drive circuit provided for each switching device includes an FET circuit and a parallel circuit made of a parallel connection of a first resistor and a first capacitor and having a first terminal connected to the gate terminal of the switching device.Type: GrantFiled: September 30, 2011Date of Patent: January 6, 2015Assignee: Hitachi, Ltd.Inventors: Ayumu Hatanaka, Kaoru Kato, Katsumi Ishikawa, Naoki Maru
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Publication number: 20140191784Abstract: The dead time is secured stably in a semiconductor drive circuit for switching devices using a wide band gap semiconductor. The drain terminal of the switching device of an upper arm is connected to the positive terminal of a first power supply, the source terminal of the switching device of a lower arm is connected to the negative terminal of the first power supply, and the source terminal of the switching device of the upper arm is connected with the drain terminal of the switching device of the lower arm. A gate drive circuit provided for each switching device includes an FET circuit and a parallel circuit made of a parallel connection of a first resistor and a first capacitor and having a first terminal connected to the gate terminal of the switching device.Type: ApplicationFiled: September 30, 2011Publication date: July 10, 2014Applicant: Hitachi, Ltd.Inventors: Ayumu Hatanaka, Kaoru Kato, Katsumi Ishikawa, Naoki Maru
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Patent number: 7911769Abstract: This invention prevents a deterioration of efficiency of a power supply apparatus due to a semiconductor power supply voltage drop, prevents an increase in wasted power, and prevents erroneous operations due to feeder wire voltage drop. In the mounting structure of electronic circuits having a plurality of busbars as current paths on a printed circuit board, the plurality of busbars have almost parallel portions spaced a predetermined distance apart; a span of the parallel portions of the plurality of busbars is greater than the predetermined distance; and in the parallel portions of the plurality of busbars, the plurality of busbars are connected by a wiring pattern. In the switching power supply apparatus built on a printed circuit board, with its output voltage of less than 2 V and its output current of more than 100 A, a means is provided for making the power efficiency higher than 70%.Type: GrantFiled: June 18, 2009Date of Patent: March 22, 2011Assignee: Hitachi, Ltd.Inventors: Hideho Yamamura, Naoki Maru, Kazunori Nakajima, Koji Nisisu, Shigeo Oomae
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Publication number: 20090257210Abstract: This invention prevents a deterioration of efficiency of a power supply apparatus due to a semiconductor power supply voltage drop, prevents an increase in wasted power, and prevents erroneous operations due to feeder wire voltage drop. In the mounting structure of electronic circuits having a plurality of busbars as current paths on a printed circuit board, the plurality of busbars have almost parallel portions spaced a predetermined distance apart; a span of the parallel portions of the plurality of busbars is greater than the predetermined distance; and in the parallel portions of the plurality of busbars, the plurality of busbars are connected by a wiring pattern. In the switching power supply apparatus built on a printed circuit board, with its output voltage of less than 2 V and its output current of more than 100 A, a means is provided for making the power efficiency higher than 70%.Type: ApplicationFiled: June 18, 2009Publication date: October 15, 2009Inventors: Hideho Yamamura, Naoki Maru, Kazunori Nakajima, Koji Nisisu, Shigeo Oomae
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Patent number: 7548411Abstract: This invention prevents a deterioration of efficiency of a power supply apparatus due to a semiconductor power supply voltage drop, prevents an increase in wasted power, and prevents erroneous operations due to feeder wire voltage drop. In the mounting structure of electronic circuits having a plurality of busbars as current paths on a printed circuit board, the plurality of busbars have almost parallel portions spaced a predetermined distance apart; a span of the parallel portions of the plurality of busbars is greater than the predetermined distance; and in the parallel portions of the plurality of busbars, the plurality of busbars are connected by a wiring pattern. In the switching power supply apparatus built on a printed circuit board, with its output voltage of less than 2 V and its output current of more than 100 A, a means is provided for making the power efficiency higher than 70%.Type: GrantFiled: October 28, 2005Date of Patent: June 16, 2009Assignee: Hitachi, Ltd.Inventors: Hideho Yamamura, Naoki Maru, Kazunori Nakajima, Koji Nisisu, Shigeo Oomae
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Patent number: 7372683Abstract: An over voltage detection circuit, which is used in a power source, a power supply system, and an electronic apparatus, includes two voltage comparison circuits. A first comparison circuit, provided for high-speed signal responses, includes voltage dividing resistors, a voltage comparator, and a reference voltage source, while a second comparison circuit, provided for low-speed signal responses, includes voltage dividing resistors, a capacitor, a voltage comparator, and a reference voltage source. The second comparison circuit, which has the capacitor, is for low-speed-signal responses and does not respond to high-speed input changes, that is, high-frequency components. The first comparison circuit, which has no capacitor, responds to any frequency components including high-speed signals and high frequency components. A high setting voltage is selected for the first comparison circuit, while a low setting voltage for the second comparison circuit.Type: GrantFiled: August 7, 2002Date of Patent: May 13, 2008Assignee: Hitachi, Ltd.Inventors: Hideho Yamamura, Naoki Maru
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Patent number: 7355829Abstract: In a redundant configuration with multiple power sources connected in parallel to enhance reliability, a power source in which an overvoltage failure occurred has been difficult to identify and unable to be deactivated, which has impeded the improvement of reliability. However, it has become possible to deactivate selectively only the power source in which an overvoltage failure has occurred, by providing a independency-discrimination circuit that identifies the occurrence of the overvoltage failure by use of the state of a parallel operation control circuit, and connecting the independency-discrimination circuit, an overvoltage detection circuit, and a connection circuit.Type: GrantFiled: September 8, 2004Date of Patent: April 8, 2008Assignees: Hitachi, Ltd., Densei-Lambda K.K.Inventors: Hideho Yamamura, Naoki Maru, Satoshi Tomioka, Motoharu Ueguri
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Patent number: 7208883Abstract: In the current detection circuit that detects the output currents of a switching power supply circuit, an improved current detection circuit makes it possible to detect the output current directions of power supplies solves the malfunction of the power supplies vibrating or diverging during changes in load state and during parallel operation, and thus implements stable operation. The direction of an output current I2 can be detected by using the current detection circuit 8 that has multiple switching elements S1 to S4 each operating synchronously with an inverter circuit.Type: GrantFiled: December 5, 2005Date of Patent: April 24, 2007Assignee: Hitachi, Ltd.Inventors: Naoki Maru, Hideho Yamamura, Koji Nisisu, Shigeo Oomae
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Publication number: 20060132062Abstract: In the current detection circuit that detects the output currents of a switching power supply circuit, an improved current detection circuit makes it possible to detect the output current directions of power supplies solves the malfunction of the power supplies vibrating or diverging during changes in load state and during parallel operation, and thus implements stable operation. The direction of an output current I2 can be detected by using the current detection circuit 8 that has multiple switching elements S1 to S4 each operating synchronously with an inverter circuit.Type: ApplicationFiled: December 5, 2005Publication date: June 22, 2006Inventors: Naoki Maru, Hideho Yamamura, Koji Nisisu, Shigeo Oomae
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Publication number: 20060092599Abstract: This invention prevents a deterioration of efficiency of a power supply apparatus due to a semiconductor power supply voltage drop, prevents an increase in wasted power, and prevents erroneous operations due to feeder wire voltage drop. In the mounting structure of electronic circuits having a plurality of busbars as current paths on a printed circuit board, the plurality of busbars have almost parallel portions spaced a predetermined distance apart; a span of the parallel portions of the plurality of busbars is greater than the predetermined distance; and in the parallel portions of the plurality of busbars, the plurality of busbars are connected by a wiring pattern. In the switching power supply apparatus built on a printed circuit board, with its output voltage of less than 2 V and its output current of more than 100 A, a means is provided for making the power efficiency higher than 70%.Type: ApplicationFiled: October 28, 2005Publication date: May 4, 2006Inventors: Hideho Yamamura, Naoki Maru, Kazunori Nakajima, Koji Nisisu, Shigeo Oomae
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Patent number: 6894882Abstract: The present invention relates generally to D.C. power supplies and more particularly to overvoltage protection in one or more D.C. power supply circuits, where a plurality of D.C. power supplies may be connected together to supply power to an electronic system. In one embodiment a D.C. power supply circuit is provided which, when used with the plurality of D.C. power supply circuits connected in parallel, is capable of stopping only the power supply circuit having run into an overvoltage state with minimal effect on the other D.C. power supply circuits. Thus power to the load is continued.Type: GrantFiled: March 6, 2001Date of Patent: May 17, 2005Assignees: Hitachi, Ltd., Hitachi Information Technology Co., Ltd.Inventors: Naoki Maru, Akihiro Sakurai, Hiroshi Kamee
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Publication number: 20050078424Abstract: In a redundant configuration with multiple power sources connected in parallel to enhance reliability, a power source in which an overvoltage failure occurred has been difficult to identify and unable to be deactivated, which has impeded the improvement of reliability. However, it has become possible to deactivate selectively only the power source in which an overvoltage failure has occurred, by providing a independency-discrimination circuit that identifies the occurrence of the overvoltage failure by use of the state of a parallel operation control circuit, and connecting the independency-discrimination circuit, an overvoltage detection circuit, and a connection circuit.Type: ApplicationFiled: September 8, 2004Publication date: April 14, 2005Inventors: Hideho Yamamura, Naoki Maru, Satoshi Tomioka, Motoharu Ueguri
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Patent number: 6628010Abstract: A parallel power system is provided which can flexibly change output currents and the number of channels in short time and at low cost. A back board 7 of the parallel power system has connectors ECC and DCC for plug-in mounting power source circuits 1 to 6 and an electronic circuit 8. Terminals of the connectors DCC and EDC are connected by wiring lines HP. The power source circuits 1 to 3 constitute a first voltage channel by a power source line DH1 and a parallel operation control line PCH1 of the electronic circuit 8, whereas the power source circuits 4 to 6 constitute a second voltage channel by a power source line DH2 and a parallel operation control line PCH2. When a specification of the electronic circuit is to be changed, only the power source lines DH1 and DH2 and parallel operation control lines PCH1 and PCH2 are changed without changing the back board 7 and the like.Type: GrantFiled: December 20, 2001Date of Patent: September 30, 2003Assignee: Hitachi, Ltd.Inventors: Hideho Yamamura, Mamoru Ogihara, Naoki Maru
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Publication number: 20030030955Abstract: An over voltage detection circuit, which is used in a power source, a power supply system, and an electronic apparatus, includes two voltage comparison circuits. A first comparison circuit, provided for high-speed signal responses, includes voltage dividing resistors, a voltage comparator, and a reference voltage source, while a second comparison circuit, provided for low-speed signal responses, includes voltage dividing resistors, a capacitor, a voltage comparator, and a reference voltage source. The second comparison circuit, which has the capacitor, is for low-speed-signal responses and does not respond to high-speed input changes, that is, high-frequency components. The first comparison circuit, which has no capacitor, responds to any frequency components including high-speed signals and high frequency components. A high setting voltage is selected for the first comparison circuit, while a low setting voltage for the second comparison circuit.Type: ApplicationFiled: August 7, 2002Publication date: February 13, 2003Inventors: Hideho Yamamura, Naoki Maru
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Publication number: 20020089865Abstract: A parallel power system is provided which can flexibly change output currents and the number of channels in short time and at low cost. A back board 7 of the parallel power system has connectors ECC and DCC for plug-in mounting power source circuits 1 to 6 and an electronic circuit 8. Terminals of the connectors DCC and EDC are connected by wiring lines HP. The power source circuits 1 to 3 constitute a first voltage channel by a power source line DH1 and a parallel operation control line PCH1 of the electronic circuit 8, whereas the power source circuits 4 to 6 constitute a second voltage channel by a power source line DH2 and a parallel operation control line PCH2. When a specification of the electronic circuit is to be changed, only the power source lines DH1 and DH2 and parallel operation control lines PCH1 and PCH2 are changed without changing the back board 7 and the like.Type: ApplicationFiled: December 20, 2001Publication date: July 11, 2002Inventors: Hideho Yamamura, Mamoru Ogihara, Naoki Maru
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Publication number: 20010020803Abstract: The present invention relates generally to D.C. power supplies and more particularly to overvoltage protection in one or more D.C. power supply circuits, where a plurality of D.C. power supplies may be connected together to supply power to an electronic system. In one embodiment a D.C. power supply circuit is provided which, when used with the plurality of D.C. power supply circuits connected in parallel, is capable of stopping only the power supply circuit having run into an overvoltage state with minimal effect on the other D.C. power supply circuits. Thus power to the load is continued.Type: ApplicationFiled: March 6, 2001Publication date: September 13, 2001Inventors: Naoki Maru, Akihiro Sakurai, Hiroshi Kamee
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Patent number: 5844762Abstract: An electronic circuit device having a power wiring resonance inhibition function includes a plurality of electronic circuit elements, and a wiring board having the electronic circuit elements disposed thereon. The wiring board includes a plurality of planar power supply wires for supplying power to the electronic circuit elements. The planar power wires include a pair of planar power supply wires for supplying power to the electronic circuit elements at a predetermined voltage. The electronic circuit device also includes a plurality of damping elements disposed at a plurality of positions on the wiring board. The damping elements are connected between the pair of planar power supply wires at a plurality of positions on the pair of planar power supply wires. The damping elements reduce power supply system impedance and inhibit power wiring system resonance, thereby reducing supply voltage fluctuation caused by the power wiring system resonance and noise caused by the supply voltage fluctuation.Type: GrantFiled: December 12, 1996Date of Patent: December 1, 1998Assignee: Hitachi, Ltd.Inventors: Hideho Yamamura, Masakazu Yamamoto, Naoki Maru, Satoshi Muraoka