Patents by Inventor Tamiji Nagai

Tamiji Nagai 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).

  • Patent number: 8098056
    Abstract: Provided is a bidirectional converter which has flexibility to be applicable in various conditions and performs stable switching of operation mode at high efficiency. An electronic device which supplies power in various conditions and operates with excellent efficiency is also provided. An electronic device is provided with a bidirectional converter, which has a reactor and four switches between power supply input terminals and a secondary battery, and a system circuit is supplied with an operation voltage through the bidirectional converter. A status signal indicating the operation status of the system circuit is transmitted to a microcomputer of the bidirectional converter, and based on the status signal, switching of operation mode of the bidirectional converter is controlled.
    Type: Grant
    Filed: July 30, 2007
    Date of Patent: January 17, 2012
    Assignee: Mitsumi Electric Co., Ltd.
    Inventors: Kazuo Yamazaki, Yukihiro Terada, Hidenori Tanaka, Tamiji Nagai, Toshio Nagai, legal representative
  • Publication number: 20110248670
    Abstract: There is provided a charging power source apparatus by which quick charging can be carried out within a required range without imposing a burden on a secondary battery or a charging circuit. The charging power source apparatus is equipped with a plurality of control modes (e.g. normal charging mode and quick charging mode) for operating respectively with a plurality of output characteristics where the magnitudes of output currents being limited are different, and a detecting circuit for detecting a voltage appearing between the output terminals, and is configured such that one of the plurality of control modes is selected based on detection result from the detection circuit to perform an output operation.
    Type: Application
    Filed: July 24, 2007
    Publication date: October 13, 2011
    Inventors: Kazuo Yamazaki, Kouji Murakami, Yukihiro Terada, Tamiji Nagai, Toshio Nagai
  • Publication number: 20100314945
    Abstract: Provided is a bidirectional converter which has flexibility to be applicable in various conditions and performs stable switching of operation mode at high efficiency. An electronic device which supplies power in various conditions and operates with excellent efficiency is also provided. An electronic device is provided with a bidirectional converter, which has a reactor and four switches between power supply input terminals and a secondary battery, and a system circuit is supplied with an operation voltage through the bidirectional converter. A status signal indicating the operation status of the system circuit is transmitted to a microcomputer of the bidirectional converter, and based on the status signal, switching of operation mode of the bidirectional converter is controlled.
    Type: Application
    Filed: July 30, 2007
    Publication date: December 16, 2010
    Applicant: MITSUMI ELECTRIC CO., LTD.
    Inventors: Kazuo Yamazaki, Yukihiro Terada, Hidenori Tanaka, Tamiji Nagai, Toshio Nagai
  • Publication number: 20100308778
    Abstract: Provided is an electronic system wherein power is accurately supplied even with a power delivery line resistance and a connector contact resistance, and furthermore, a plurality of electronic devices having requiring different power supply voltages can be handled with one power supply device. The electronic system is provided with an electronic device (50), and a power supply device (10) which is arranged to be connected/removed to and from the electronic device (50) and supplies power through a cable when connected. The electronic device (50) is provided with a first detection circuit (51) for performing detection relating to the supply amount of the power supply and outputting a first detection signal, and a control signal terminal.
    Type: Application
    Filed: August 28, 2007
    Publication date: December 9, 2010
    Inventors: Kazuo Yamazaki, Yukihiro Terada, Kouji Murakami, Tamiji Nagai, Toshio Nagai
  • Patent number: 7830675
    Abstract: To reduce power loss during standby. In a switching power supply device using a first power supply circuit (11) having a small output and a second power supply circuit (12) having a large output, the first power supply circuit (11) is continuously kept in an operating state and the second power supply circuit (12) is started by using an electric power generated in the first power supply circuit (11).
    Type: Grant
    Filed: November 27, 2006
    Date of Patent: November 9, 2010
    Assignee: Mitsumi Electric Co., Ltd.
    Inventors: Tamiji Nagai, Toshio Nagai, legal representative, Kazuo Yamazaki
  • Publication number: 20100188051
    Abstract: The present invention provides a highly safe charging circuit with which overcharge of a secondary battery will never occur even when a failure occurs in a transistor or the like that controls the charging voltage or charging current or when a protection circuit does not operate normally. In a secondary battery charging circuit 4 that charges a secondary battery E2 with an input power source voltage, the power source voltage is set to a voltage (e.g. 4.0 V) that is lower than the full-charge voltage (e.g. 4.2 V) of the secondary battery. When the voltage of the secondary battery E2 is lower than the power source voltage, a constant current circuit operates to perform constant current charging without voltage step-up, and when the voltage of the secondary battery E2 is higher than the power source voltage and lower than the full-charge voltage, a voltage step-up circuit operates to perform constant current charging with voltage step-up.
    Type: Application
    Filed: June 13, 2007
    Publication date: July 29, 2010
    Applicant: MITSUMI ELECTRIC CO; LTD.
    Inventors: Kazuo Yamazaki, Hidenori Tanaka, Yukihiro Terada, Tamiji Nagai, Toshio Nagai
  • Publication number: 20100135048
    Abstract: To reduce power loss during standby. In a switching power supply device using a first power supply circuit (11) having a small output and a second power supply circuit (12) having a large output, the first power supply circuit (11) is continuously kept in an operating state and the second power supply circuit (12) is started by using an electric power generated in the first power supply circuit (11).
    Type: Application
    Filed: November 27, 2006
    Publication date: June 3, 2010
    Applicant: Mitsumi Electric Company., Ltd.
    Inventors: Tamiji Nagai, Toshio Nagai, Kazuo Yamazaki
  • Publication number: 20100127676
    Abstract: Disclosed is a power source apparatus including: a connector for outputting electric power, wherein the apparatus performs power output through a cable connected to the connector, a power source circuit capable of changing an output thereof; a control circuit to perform output control of the power source circuit; and a first detection circuit including an input terminal for detection connected to wiring on a side of a tip of the cable to perform detection pertaining to an output quantity of electric power, wherein the output control is performed based on a detection signal of the first detection circuit, the detection signal fed back to the control circuit.
    Type: Application
    Filed: August 28, 2007
    Publication date: May 27, 2010
    Applicant: Mitsumi Electric Co. Ltd.
    Inventors: Kazuo Yamazaki, Yukihiro Terada, Kouji Murakami, Tamiji Nagai, Toshio Nagai
  • Patent number: 7436644
    Abstract: A solenoid type switch has at least two driving coils. The driving coils turn off a switch with a current for example an overcurrent that flows in the switch. The driving coils are magnetized or demagnetized by a driving circuit so as to turn on or off the switch. The driving circuit magnetizes or demagnetizes the driving coils in accordance with a control signal supplied from a controlling circuit. Thus, the switch can be turned off with the current that flows in the driving coils.
    Type: Grant
    Filed: December 12, 2003
    Date of Patent: October 14, 2008
    Assignee: Sony Corporation
    Inventors: Tamiji Nagai, Kazuo Yamazaki, Hitoshi Akiho, Takayuki Aita, Kenji Enomoto
  • Patent number: 7202633
    Abstract: A driving circuit is disclosed. The driving circuit comprises a secondary battery cell having a positive electrode and a negative electrode, first and second N-type field effect transistors each having a gate, a drain, and a source, first and second switching devices, connected between the gates of the first and second N-type field effect transistors and the negative electrode side of the secondary battery cell, for turning on and off the first and second N-type field effect transistors, driving means for controlling the first and second switching devices, first and second output terminals, and a diode having an anode and a cathode.
    Type: Grant
    Filed: June 24, 2004
    Date of Patent: April 10, 2007
    Assignee: Sony Corporation
    Inventors: Tamiji Nagai, Kazuo Yamazaki, Kenji Enomoto, Takayuki Aita
  • Patent number: 7193390
    Abstract: When an output voltage of a secondary battery cell E1 is obtained, only SW1 and SW2 are turned on. As a result, a capacitor C1 is charged by a secondary battery cell E1. With a delay of a time period √ĄT, SW1 and SW2 are turned off. SW4 and SW5 are turned on. As a result, electric charges of the capacitor C1 are moved to a capacitor C2. Those operations are repeated until the potential of the capacitor C2 becomes almost equal to the output voltage of the secondary battery cell E1. When the potential of the capacitor C2 becomes almost equal to the output voltage of the capacitor C2, the potential of the capacitor C2 is detected by the voltage detector 11. A first terminal of the capacitor C2 is connected to a ground potential. As a result, the voltage of the secondary battery cell E1 can be stably detected. When the secondary battery cell E2 is detected, only SW5 is turned on. As a result, the capacitor C2 is charged by the secondary battery cell E2.
    Type: Grant
    Filed: May 1, 2003
    Date of Patent: March 20, 2007
    Assignee: Sony Corporation
    Inventors: Tamiji Nagai, Kazuo Yamazaki, Tamon Ikeda
  • Patent number: 7023179
    Abstract: In the case of charging by a charging apparatus having a plurality of input terminals to which external power sources for charging a secondary battery are inputted, it is prevented that a current of the inputted power source is outputted to the outside from the other input terminals for charging which are not used. If there are inputs from a plurality of input terminals, the input power sources are controlled so that the battery is optimally charged. pnp-type transistors Q1 and Q2 are arranged between two input terminals of a terminal 11 for an external power adaptor and a terminal 12 for a holder and a secondary battery E1, respectively. When a control IC 13 detects an input power voltage of one of the transistors, the transistor on the detected side is turned on. If the control IC 13 detects both input power voltages, a priority is allocated under predetermined conditions and the secondary battery E1 is charged by the power source of the higher priority.
    Type: Grant
    Filed: May 1, 2003
    Date of Patent: April 4, 2006
    Assignee: Sony Corporation
    Inventors: Tamiji Nagai, Kazuo Yamazaki, Tadahisa Yamamoto
  • Patent number: 7023180
    Abstract: In the case of charging by a charging apparatus having a plurality of input terminals to which external power sources for charging a secondary battery are inputted, it is prevented that a current of the inputted power source is outputted to the outside from the other input terminals for charging which are not used. If there are inputs from a plurality of input terminals, the input power sources are controlled so that the battery is optimally charged. pnp-type transistors Q1 and Q2 are arranged between two input terminals of a terminal 11 for an external power adaptor and a terminal 12 for a holder and a secondary battery E1, respectively. When a control IC 13 detects an input power voltage of one of the transistors, the transistor on the detected side is turned on. If the control IC 13 detects both input power voltages, a priority is allocated under predetermined conditions and the secondary battery E1 is charged by the power source of the higher priority.
    Type: Grant
    Filed: April 11, 2005
    Date of Patent: April 4, 2006
    Assignee: Sony Corporation
    Inventors: Tamiji Nagai, Kazuo Yamazaki, Tadahisa Yamamoto
  • Patent number: 6961255
    Abstract: A commercially available power source is rectified by a diode bridge and a capacitor and supplied to a transformer via a terminal. One end of a primary coil is connected to the terminal and the other end is connected to a switching device. One end of a feedback coil is connected to the switching device and the other end is connected to the terminal. A negative feedback circuit is provided between the switching device and the terminal. A rectifying circuit comprising a diode and a capacitor is provided on a secondary coil. A node of the coil and the capacitor is connected to the terminal via a resistor. In detecting circuits, a voltage across the terminal is detected and a current across the resistor is detected. When the detected voltage and current are equal to predetermined values, a control signal is supplied to a feedback circuit.
    Type: Grant
    Filed: April 4, 2005
    Date of Patent: November 1, 2005
    Assignee: Sony Corporation
    Inventors: Tamiji Nagai, Tamon Ikeda, Kazuo Yamazaki
  • Patent number: 6956754
    Abstract: A commercially available power source is rectified by a diode bridge and a capacitor and supplied to a transformer via a terminal. One end of a primary coil is connected to the terminal and the other end is connected to a switching device. One end of a feedback coil is connected to the switching device and the other end is connected to the terminal. A negative feedback circuit is provided between the switching device and the terminal. A rectifying circuit comprising a diode and a capacitor is provided on a secondary coil. A node of the coil and the capacitor is connected to the terminal via a resistor. In detecting circuits, a voltage across the terminal is detected and a current across the resistor is detected. When the detected voltage and current are equal to predetermined values, a control signal is supplied to a feedback circuit.
    Type: Grant
    Filed: April 4, 2005
    Date of Patent: October 18, 2005
    Assignee: Sony Corporation
    Inventors: Tamiji Nagai, Tamon Ikeda, Kazuo Yamazaki
  • Patent number: 6956357
    Abstract: In the case of charging by a charging apparatus having a plurality of input terminals to which external power sources for charging a secondary battery are inputted, it is prevented that a current of the inputted power source is outputted to the outside from the other input terminals for charging which are not used. If there are inputs from a plurality of input terminals, the input power sources are controlled so that the battery is optimally charged. pnp-type transistors Q1 and Q2 are arranged between two input terminals of a terminal 11 for an external power adaptor and a terminal 12 for a holder and a secondary battery E1, respectively. When a control IC 13 detects an input power voltage of one of the transistors, the transistor on the detected side is turned on. If the control IC 13 detects both input power voltages, a priority is allocated under predetermined conditions and the secondary battery E1 is charged by the power source of the higher priority.
    Type: Grant
    Filed: April 11, 2005
    Date of Patent: October 18, 2005
    Assignee: Sony Corporation
    Inventors: Tamiji Nagai, Kazuo Yamazaki, Tadahisa Yamamoto
  • Patent number: 6949913
    Abstract: In the case of charging by a charging apparatus having a plurality of input terminals to which external power sources for charging a secondary battery are inputted, it is prevented that a current of the inputted power source is outputted to the outside from the other input terminals for charging which are not used. If there are inputs from a plurality of input terminals, the input power sources are controlled so that the battery is optimally charged. pnp-type transistors Q1 and Q2 are arranged between two input terminals of a terminal 11 for an external power adaptor and a terminal 12 for a holder and a secondary battery E1, respectively. When a control IC 13 detects an input power voltage of one of the transistors, the transistor on the detected side is turned on. If the control IC 13 detects both input power voltages, a priority is allocated under predetermined conditions and the secondary battery E1 is charged by the power source of the higher priority.
    Type: Grant
    Filed: April 11, 2005
    Date of Patent: September 27, 2005
    Assignee: Sony Corporation
    Inventors: Tamiji Nagai, Kazuo Yamazaki, Tadahisa Yamamoto
  • Publication number: 20050189925
    Abstract: In the case of charging by a charging apparatus having a plurality of input terminals to which external power sources for charging a secondary battery are inputted, it is prevented that a current of the inputted power source is outputted to the outside from the other input terminals for charging which are not used. If there are inputs from a plurality of input terminals, the input power sources are controlled so that the battery is optimally charged. pnp-type transistors Q1 and Q2 are arranged between two input terminals of a terminal 11 for an external power adaptor and a terminal 12 for a holder and a secondary battery E1, respectively. When a control IC 13 detects an input power voltage of one of the transistors, the transistor on the detected side is turned on. If the control IC 13 detects both input power voltages, a priority is allocated under predetermined conditions and the secondary battery E1 is charged by the power source of the higher priority.
    Type: Application
    Filed: April 11, 2005
    Publication date: September 1, 2005
    Inventors: Tamiji Nagai, Kazuo Yamazaki, Tadahisa Yamamoto
  • Publication number: 20050189926
    Abstract: In the case of charging by a charging apparatus having a plurality of input terminals to which external power sources for charging a secondary battery are inputted, it is prevented that a current of the inputted power source is outputted to the outside from the other input terminals for charging which are not used. If there are inputs from a plurality of input terminals, the input power sources are controlled so that the battery is optimally charged. pnp-type transistors Q1 and Q2 are arranged between two input terminals of a terminal 11 for an external power adaptor and a terminal 12 for a holder and a secondary battery E1, respectively. When a control IC 13 detects an input power voltage of one of the transistors, the transistor on the detected side is turned on. If the control IC 13 detects both input power voltages, a priority is allocated under predetermined conditions and the secondary battery E1 is charged by the power source of the higher priority.
    Type: Application
    Filed: April 11, 2005
    Publication date: September 1, 2005
    Inventors: Tamiji Nagai, Kazuo Yamazaki, Tadahisa Yamamoto
  • Publication number: 20050189924
    Abstract: In the case of charging by a charging apparatus having a plurality of input terminals to which external power sources for charging a secondary battery are inputted, it is prevented that a current of the inputted power source is outputted to the outside from the other input terminals for charging which are not used. If there are inputs from a plurality of input terminals, the input power sources are controlled so that the battery is optimally charged. pnp-type transistors Q1 and Q2 are arranged between two input terminals of a terminal 11 for an external power adaptor and a terminal 12 for a holder and a secondary battery E1, respectively. When a control IC 13 detects an input power voltage of one of the transistors, the transistor on the detected side is turned on. If the control IC 13 detects both input power voltages, a priority is allocated under predetermined conditions and the secondary battery E1 is charged by the power source of the higher priority.
    Type: Application
    Filed: April 11, 2005
    Publication date: September 1, 2005
    Inventors: Tamiji Nagai, Kazuo Yamazaki, Tadahisa Yamamoto