Patents by Inventor Kazuhiko Ishimoto

Kazuhiko Ishimoto 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: 11880218
    Abstract: A current output circuit includes an input circuit that outputs a second current in response to a first current when the first current is inputted, an output circuit that outputs a third current in response to the second current, and a control circuit that causes the output circuit to output a current when a control signal is inputted before the first current is inputted to the input circuit. The output circuit includes transistors of a first group and the input circuit includes transistors of a second group.
    Type: Grant
    Filed: May 25, 2021
    Date of Patent: January 23, 2024
    Assignee: MURATA MANUFACTURING CO., LTD.
    Inventor: Kazuhiko Ishimoto
  • Publication number: 20230216454
    Abstract: A current control circuit controls a bias current that is supplied to an amplifier transistor that amplifies a radio-frequency signal and includes a node, a constant current source circuit that supplies a first current to the node, and a variable current source circuit that supplies a second current to the node, based on a result of comparison between a potential of the node and a reference potential. The node outputs a control current including the first current and the second current for controlling the bias current.
    Type: Application
    Filed: March 13, 2023
    Publication date: July 6, 2023
    Inventor: Kazuhiko ISHIMOTO
  • Patent number: 11489493
    Abstract: A current control circuit controls a base current of a first transistor included in a bias circuit outputting a bias current to a power amplifier based on a base-collector voltage of the first transistor. The current control circuit includes a first circuit that outputs a signal associated with the base-collector voltage of the first transistor, and a second circuit that, based on the signal, provides electrical continuity between a base of the first transistor and a reference potential.
    Type: Grant
    Filed: February 4, 2020
    Date of Patent: November 1, 2022
    Assignee: MURATA MANUFACTURING CO., LTD.
    Inventors: Mikiko Fukasawa, Kazuhiko Ishimoto
  • Publication number: 20210278871
    Abstract: A current output circuit includes an input circuit that outputs a second current in response to a first current when the first current is inputted, an output circuit that outputs a third current in response to the second current, and a control circuit that causes the output circuit to output a current when a control signal is inputted before the first current is inputted to the input circuit. The output circuit includes transistors of a first group and the input circuit includes transistors of a second group.
    Type: Application
    Filed: May 25, 2021
    Publication date: September 9, 2021
    Inventor: Kazuhiko ISHIMOTO
  • Publication number: 20210234523
    Abstract: There is provided a power amplifier circuit with improved operation speed of the protection function against overcurrent or overvoltage. The power amplifier circuit includes an amplifier configured to amplify a radio frequency signal and output the radio frequency signal, a bias current supply circuit configured to supply a bias current to the amplifier, a detection circuit configured to detect whether the current or voltage of the amplifier is equal to or greater than a predetermined threshold; and a draw circuit configured to, when the detection circuit detects that the current or voltage is equal to or greater than the predetermined threshold, draw at least a part of the bias current supplied to the amplifier.
    Type: Application
    Filed: April 14, 2021
    Publication date: July 29, 2021
    Inventors: Fuminori MORISAWA, Kazuhiko ISHIMOTO, Fumio HARIMA
  • Publication number: 20200252029
    Abstract: A current control circuit controls a base current of a first transistor included in a bias circuit outputting a bias current to a power amplifier based on a base-collector voltage of the first transistor. The current control circuit includes a first circuit that outputs a signal associated with the base-collector voltage of the first transistor, and a second circuit that, based on the signal, provides electrical continuity between a base of the first transistor and a reference potential.
    Type: Application
    Filed: February 4, 2020
    Publication date: August 6, 2020
    Inventors: Mikiko FUKASAWA, Kazuhiko ISHIMOTO
  • Patent number: 9240760
    Abstract: A power amplifier module includes a first amplification transistor that amplifies and outputs a radio frequency signal, a second amplification transistor that is connected in parallel to the first amplification transistor and that has a smaller size than the first amplification transistor, a bias circuit that supplies a bias voltage or a bias current to the first and second amplification transistors, a current detector circuit that detects a current flowing in the second amplification transistor, and a bias control circuit that controls the bias voltage or the bias current supplied from the bias circuit to the first and second amplification transistors depending on the detection result of the current detector circuit.
    Type: Grant
    Filed: November 13, 2014
    Date of Patent: January 19, 2016
    Assignee: MURATA MANUFACTURING CO., LTD.
    Inventors: Kazuhiko Ishimoto, Takashi Soga
  • Publication number: 20150070092
    Abstract: A power amplifier module includes a first amplification transistor that amplifies and outputs a radio frequency signal, a second amplification transistor that is connected in parallel to the first amplification transistor and that has a smaller size than the first amplification transistor, a bias circuit that supplies a bias voltage or a bias current to the first and second amplification transistors, a current detector circuit that detects a current flowing in the second amplification transistor, and a bias control circuit that controls the bias voltage or the bias current supplied from the bias circuit to the first and second amplification transistors depending on the detection result of the current detector circuit.
    Type: Application
    Filed: November 13, 2014
    Publication date: March 12, 2015
    Inventors: Kazuhiko Ishimoto, Takashi Soga
  • Patent number: 7332966
    Abstract: A high frequency power amplifier circuit includes amplifying devices whose control terminals (gate or base terminals) are supplied with a bias voltage. The high frequency power amplifier circuit keeps constant the bias voltage so that the amplifying devices operate in a saturation region. The high frequency power amplifier circuit controls an operating power supply voltage supplied to the amplifying devices in accordance with an output request level to control output power. A device (diode) having temperature dependency is provided for an operating power supply voltage control circuit that controls the operating power supply voltage for the amplifying devices in accordance with the output request level. The operating power supply voltage control circuit is configured to generate the operating power supply voltage corresponding to the device's temperature characteristics and supply it to the amplifying devices.
    Type: Grant
    Filed: March 9, 2006
    Date of Patent: February 19, 2008
    Assignee: Renesas Technology Corp.
    Inventors: Tomio Furuya, Kazuhiko Ishimoto, Hiroyuki Tanaka
  • Patent number: 7271658
    Abstract: An RF power module in which operating voltage is controlled by a control signal based on amplitude information includes a temperature detecting device which is provided over a semiconductor chip formed with an amplifying transistor or a semiconductor chip formed with a power source circuit; and a detector having a hysteresis characteristic which is provided over the semiconductor chip formed with the device or a different semiconductor chip, applies a bias to the temperature detecting device to compare the state of the device at two reference levels, outputs a signal indicating abnormality when judging that the temperature of the semiconductor chip formed with the temperature detecting device is above a predetermined temperature, and outputs a signal indicating normality when judging that the temperature of the semiconductor chip is below a second predetermined temperature lower than the predetermined temperature.
    Type: Grant
    Filed: June 10, 2005
    Date of Patent: September 18, 2007
    Assignees: Renesas Technology Corp., Hitachi Hybrid Network, Co., Ltd.
    Inventors: Kouichi Matsushita, Kenichi Shimamoto, Kazuhiro Koshio, Kazuhiko Ishimoto, Takayuki Tsutsui
  • Publication number: 20060214729
    Abstract: A high frequency power amplifier circuit includes amplifying devices whose control terminals (gate or base terminals) are supplied with a bias voltage. The high frequency power amplifier circuit keeps constant the bias voltage so that the amplifying devices operate in a saturation region. The high frequency power amplifier circuit controls an operating power supply voltage supplied to the amplifying devices in accordance with an output request level to control output power. A device (diode) having temperature dependency is provided for an operating power supply voltage control circuit that controls the operating power supply voltage for the amplifying devices in accordance with the output request level. The operating power supply voltage control circuit is configured to generate the operating power supply voltage corresponding to the device's temperature characteristics and supply it to the amplifying devices.
    Type: Application
    Filed: March 9, 2006
    Publication date: September 28, 2006
    Inventors: Tomio Furuya, Kazuhiko Ishimoto, Hiroyuki Tanaka
  • Publication number: 20050280471
    Abstract: An RF power module in which operating voltage is controlled by a control signal based on amplitude information includes a temperature detecting device which is provided over a semiconductor chip formed with an amplifying transistor or a semiconductor chip formed with a power source circuit; and a detector having a hysteresis characteristic which is provided over the semiconductor chip formed with the device or a different semiconductor chip, applies a bias to the temperature detecting device to compare the state of the device at two reference levels, outputs a signal indicating abnormality when judging that the temperature of the semiconductor chip formed with the temperature detecting device is above a predetermined temperature, and outputs a signal indicating normality when judging that the temperature of the semiconductor chip is below a second predetermined temperature lower than the predetermined temperature.
    Type: Application
    Filed: June 10, 2005
    Publication date: December 22, 2005
    Inventors: Kouichi Matsushita, Kenichi Shimamoto, Kazuhiro Koshio, Kazuhiko Ishimoto, Takayuki Tsutsui