Patents by Inventor Hiroshi Kunitama

Hiroshi Kunitama 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).

  • Publication number: 20250119108
    Abstract: This high frequency amplifier includes: an amplifier that amplifies a high frequency signal; and an impedance adjustment unit that adjusts impedance relative to a high frequency wave as seen from the amplifier to a load side. The impedance adjustment unit includes a distributed constant circuit and a lumped constant circuit. The distributed constant circuit includes a transmission line that resonates with harmonics, and the lumped constant circuit includes a resonance circuit that resonates with a fundamental wave and harmonics other than the harmonics of the distributed constant circuit. One end of the transmission line of the distributed constant circuit is an open end, and is constituted from an open stub provided with a line length that resonates with various harmonics. The high frequency amplifier carries out filtering by adjusting the impedance of the fundamental wave and the harmonics without being provided with a fundamental wave 1/4 wavelength transmission line.
    Type: Application
    Filed: August 1, 2022
    Publication date: April 10, 2025
    Applicant: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Hiroshi Kunitama, Takuya Yoshida
  • Publication number: 20250007142
    Abstract: A nonreciprocal circuit element according to the present invention comprises a nonreciprocal unit provided with a ferrite, an electromagnet that applies a DC magnetic field to the ferrite, and conductors that are arranged so as to intersect with each other in an insulated state with respect to the ferrite and that have a plurality of shorted terminal ends. The nonreciprocal circuit element comprises reciprocal circuit units and a DC power supply control unit controlling DC current to be supplied to the electromagnet. The DC power supply control unit controls the DC current to be supplied to the electromagnet and controls a DC magnetic field to be applied to the electromagnet. By the control of the DC magnetic field, the center frequency of frequency characteristics of the nonreciprocal circuit element is matched with the frequency of a high-frequency signal, and insertion loss of the nonreciprocal circuit element is reduced.
    Type: Application
    Filed: June 21, 2022
    Publication date: January 2, 2025
    Applicant: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Hiroshi Kunitama, Takuya Yoshida
  • Publication number: 20240146174
    Abstract: A power conversion device according to the present invention comprises a plurality of class-D amplifiers disposed in parallel. An ON/OFF operation of a switching element of a lead leg and a delay leg of each class-D amplifier is carried out by a phase shift control, in which an auxiliary current is supplied to the class-D amplifier on the basis of a voltage difference between output terminals of an upper and lower class-D amplifiers. The auxiliary current supplements the electric current flowing between the drain and the source of the switching element. Generation of a displacement voltage dv/dt on the switching element, and a displacement current di/dt in modulation waves generated by the displacement voltage are prevented, thus preventing erroneous turn-on of the switching element in the OFF state of the other side of the leg.
    Type: Application
    Filed: February 28, 2022
    Publication date: May 2, 2024
    Applicant: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Koichi Miyazaki, Hiroshi Kunitama
  • Publication number: 20240113667
    Abstract: The switching module has, mounted on a substrate thereof, a MOSFET and a driver circuit for applying drive voltage to a gate electrode of the MOSFET. In the switching module according to the present invention, the driver circuit is electrically connected to the MOSFET via a damping adjustment element and a bonding wire between the gate electrode and the driver circuit.
    Type: Application
    Filed: October 30, 2019
    Publication date: April 4, 2024
    Applicant: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Hiroshi Kunitama, Takuya Yoshida
  • Publication number: 20230421152
    Abstract: A switching module comprising: a GaN-FET mounted on a substrate; a driver circuit connected to a gate electrode of the GaN-FET via a gate resistor; and a driver power supply for supplying a drive voltage to the driver circuit. The driver circuit is configured such that a plurality of logic integrated circuits are connected in parallel.
    Type: Application
    Filed: June 22, 2021
    Publication date: December 28, 2023
    Applicant: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Hiroshi Kunitama, Takuya Yoshida
  • Publication number: 20230134084
    Abstract: A high-frequency power supply device is provided with an AC-DC converter for converting an input from a three-phase alternating-current source into a direct current and a high-frequency amplifier including multiple FET elements and outputting a high-frequency alternating-current power, with the output of the AC-DC converter being directly input to the high-frequency amplifier, and further includes a phase conversion circuit for imparting phase differences to gate signals to be input to the multiple FET elements so as to offset fluctuation components included in the direct current. The device generates the high-frequency alternating-current power by converting the input from the three-phase alternating-current source into the direct current, directly inputting the direct current to the high-frequency amplifier, imparting the phase differences to the gate signals to be input to the multiple FET elements so as to offset the fluctuation components included in the direct current, and performing switching.
    Type: Application
    Filed: December 24, 2020
    Publication date: May 4, 2023
    Applicant: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Hiroshi Kunitama, Kunihiro Muto, Takuya Yoshida, Koichi Miyazaki
  • Patent number: 11368088
    Abstract: Provided is multi-phase interleaving control in a power supply device, the control allowing the pulse widths ?T of respective phases to overlap one another, so as to be adaptable to wideband pulse power control. In applying dead beat control to the multi-phase interleaving, constant current control is performed using combined current of the respective phase current values, and the pulse widths ?T(k) is computed under this constant current control, thereby preventing variation of the pulse widths ?T(k) between the phases, and achieving stable power control. Accordingly, the pulse power control becomes adaptable to wideband. Furthermore, wideband control is possible also in two-level pulse power control that performs control by switching at high frequency between High-level power and Low-level power.
    Type: Grant
    Filed: February 23, 2017
    Date of Patent: June 21, 2022
    Assignee: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Ryosuke Ohma, Hiroshi Kunitama, Yu Hosoyamada
  • Patent number: 10992217
    Abstract: To suppress a leakage current flowing through a parasitic capacitor of an insulated transformer of a high-side insulated power. The present invention suppresses a common mode current using a common mode reactor by focusing on the fact that a leakage current flowing through a parasitic capacitor of an insulated transformer of a high-side insulated power source resulting from a high-frequency signal generated due to an on/off operation of a high-side switching element is the common mode current. The common mode reactor reduces the common mode current and bears the high-frequency signal to prevent the high-frequency signal from being applied to the insulated transformer of the high-side insulated power source, suppress the leakage current flowing through the parasitic capacitor of the insulated transformer, and reduce an erroneous operation of the high-side switching element generated due to the leakage current flowing through the parasitic capacitor of the insulated transformer.
    Type: Grant
    Filed: February 23, 2017
    Date of Patent: April 27, 2021
    Assignee: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Ryosuke Ohma, Hiroshi Kunitama, Yu Hosoyamada
  • Patent number: 10978950
    Abstract: Provided is multi-phase interleaving control in a power supply device. In power control by the power supply device where the dead beat control is applied to the multi-phase interleaving, combined current of the multi-phase current values is used as control current in the multi-phase control based on the multi-phase interleaving, thereby achieving control independent of the number of the detectors and the control system independent of the number of phases, and further, this control current is used to perform constant current control, so as to prevent overshooting and undershooting. The power supply device has multi-phase interleaving control that performs multi-phase control using a plurality of phase current values, provided with an LC chopper circuit constituting a step-down chopper circuit that operates according to the multi-phase control of multi-phase interleaving, and a controller for performing step response control according to the multi-phase control of the LC chopper circuit.
    Type: Grant
    Filed: February 23, 2017
    Date of Patent: April 13, 2021
    Assignee: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Ryosuke Ohma, Hiroshi Kunitama, Yu Hosoyamada
  • Patent number: 10924007
    Abstract: Multi-phase interleaving control in a power supply device is accelerated. In addition, in accelerating the multi-phase interleaving control in the power supply device, acceleration in detecting a feedback signal and stabilization of a control system in a high-frequency band are promoted. Eliminating the need of the feedback signal according to a slow response detector, and using a detection signal obtained by a detector for detecting an AC signal capable of rapid response, thereby accelerating the multi-phase interleaving control in the power supply device. Then, the control system is stabilized, by satisfying a condition where gain is equal to 1 or less in a transfer function of the control system including an LC circuit, and a condition where a phase shift caused by dead time of switching time does not affect the sampling cycle.
    Type: Grant
    Filed: February 23, 2017
    Date of Patent: February 16, 2021
    Assignee: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Ryosuke Ohma, Hiroshi Kunitama, Yu Hosoyamada
  • Patent number: 10886850
    Abstract: Multi-phase interleaving control of a power supply device is accelerated. Furthermore, in accelerating the multi-phase interleaving control in the power supply device, detection of feedback signal is accelerated. In the power supply device and a method for controlling the power supply device, output voltage is acquired as an operation result of a discrete time process using an initial value of the output voltage at a predetermined point, and a detection value of capacitance current at each point of the discrete time process. Accordingly, only detection of the initial value is performed when the output voltage being slow in response is acquired, and detection performed in the discrete time process can be accomplished by detection of capacitance current being rapid in response, thus enabling rapid response.
    Type: Grant
    Filed: February 23, 2017
    Date of Patent: January 5, 2021
    Assignee: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Ryosuke Ohma, Hiroshi Kunitama, Yu Hosoyamada
  • Publication number: 20200153339
    Abstract: Provided is multi-phase interleaving control in a power supply device, the control allowing the pulse widths ?T of respective phases to overlap one another, so as to be adaptable to wideband pulse power control. In applying dead beat control to the multi-phase interleaving, constant current control is performed using combined current of the respective phase current values, and the pulse widths ?T(k) is computed under this constant current control, thereby preventing variation of the pulse widths ?T(k) between the phases, and achieving stable power control. Accordingly, the pulse power control becomes adaptable to wideband. Furthermore, wideband control is possible also in two-level pulse power control that performs control by switching at high frequency between High-level power and Low-level power.
    Type: Application
    Filed: February 23, 2017
    Publication date: May 14, 2020
    Applicant: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Ryosuke Ohma, Hiroshi Kunitama, Yu Hosoyamada
  • Publication number: 20200144920
    Abstract: Multi-phase interleaving control of a power supply device is accelerated. Furthermore, in accelerating the multi-phase interleaving control in the power supply device, detection of feedback signal is accelerated. In the power supply device and a method for controlling the power supply device, output voltage is acquired as an operation result of a discrete time process using an initial value of the output voltage at a predetermined point, and a detection value of capacitance current at each point of the discrete time process. Accordingly, only detection of the initial value is performed when the output voltage being slow in response is acquired, and detection performed in the discrete time process can be accomplished by detection of capacitance current being rapid in response, thus enabling rapid response.
    Type: Application
    Filed: February 23, 2017
    Publication date: May 7, 2020
    Applicant: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Ryosuke Ohma, Hiroshi Kunitama, Yu Hosoyamada
  • Publication number: 20200144921
    Abstract: Provided is multi-phase interleaving control in a power supply device. In power control by the power supply device where the dead beat control is applied to the multi-phase interleaving, combined current of the multi-phase current values is used as control current in the multi-phase control based on the multi-phase interleaving, thereby achieving control independent of the number of the detectors and the control system independent of the number of phases, and further, this control current is used to perform constant current control, so as to prevent overshooting and undershooting. The power supply device has multi-phase interleaving control that performs multi-phase control using a plurality of phase current values, provided with an LC chopper circuit constituting a step-down chopper circuit that operates according to the multi-phase control of multi-phase interleaving, and a controller for performing step response control according to the multi-phase control of the LC chopper circuit.
    Type: Application
    Filed: February 23, 2017
    Publication date: May 7, 2020
    Applicant: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Ryosuke Ohma, Hiroshi Kunitama, Yu Hosoyamada
  • Patent number: 10594220
    Abstract: A chopper section of a power supply device includes a plurality of step-down chopper circuits, and multiphase control of the step-down chopper circuits is performed using gate signals having phases displaced from each other. This shortens the period with which output signals of the step-down chopper circuits are changed. Shortening the period reduces the amount of jitter resulting from a gap between the occurrence of a command signal and a sampling point that is a point in time at which a gate signal is generated. The number of phases of the gate signals equals the number of phases of the step-down chopper circuits. The control of the gate signal generator is asynchronous to feedback control by the controller. Points in time (sampling points) at which gate signals are generated are points in time of generation (sampling points) after a point in time at which the controller calculates a manipulated value.
    Type: Grant
    Filed: February 23, 2017
    Date of Patent: March 17, 2020
    Assignee: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Takeshi Fujiwara, Ryosuke Ohma, Hiroshi Kunitama, Satoshi Kawai, Ryota Suzuki
  • Publication number: 20190341847
    Abstract: To suppress a leakage current flowing through a parasitic capacitor of an insulated transformer of a high-side insulated power. The present invention suppresses a common mode current using a common mode reactor by focusing on the fact that a leakage current flowing through a parasitic capacitor of an insulated transformer of a high-side insulated power source resulting from a high-frequency signal generated due to an on/off operation of a high-side switching element is the common mode current. The common mode reactor reduces the common mode current and bears the high-frequency signal to prevent the high-frequency signal from being applied to the insulated transformer of the high-side insulated power source, suppress the leakage current flowing through the parasitic capacitor of the insulated transformer, and reduce an erroneous operation of the high-side switching element generated due to the leakage current flowing through the parasitic capacitor of the insulated transformer.
    Type: Application
    Filed: February 23, 2017
    Publication date: November 7, 2019
    Applicant: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Ryosuke Ohma, Hiroshi Kunitama, Yu Hosoyamada
  • Publication number: 20190341851
    Abstract: A chopper section of a power supply device includes a plurality of step-down chopper circuits, and multiphase control of the step-down chopper circuits is performed using gate signals having phases displaced from each other. This shortens the period with which output signals of the step-down chopper circuits are changed. Shortening the period reduces the amount of jitter resulting from a gap between the occurrence of a command signal and a sampling point that is a point in time at which a gate signal is generated. The number of phases of the gate signals equals the number of phases of the step-down chopper circuits. The control of the gate signal generator is asynchronous to feedback control by the controller. Points in time (sampling points) at which gate signals are generated are points in time of generation (sampling points) after a point in time at which the controller calculates a manipulated value.
    Type: Application
    Filed: February 23, 2017
    Publication date: November 7, 2019
    Applicant: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Takeshi Fujiwara, Ryosuke Ohma, Hiroshi Kunitama, Satoshi Kawai, Ryota Suzuki
  • Publication number: 20190319535
    Abstract: Multi-phase interleaving control in a power supply device is accelerated. In addition, in accelerating the multi-phase interleaving control in the power supply device, acceleration in detecting a feedback signal and stabilization of a control system in a high-frequency band are promoted. Eliminating the need of the feedback signal according to a slow response detector, and using a detection signal obtained by a detector for detecting an AC signal capable of rapid response, thereby accelerating the multi-phase interleaving control in the power supply device. Then, the control system is stabilized, by satisfying a condition where gain is equal to 1 or less in a transfer function of the control system including an LC circuit, and a condition where a phase shift caused by dead time of switching time does not affect the sampling cycle.
    Type: Application
    Filed: February 23, 2017
    Publication date: October 17, 2019
    Applicant: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Ryosuke Ohma, Hiroshi Kunitama, Yu Hosoyamada
  • Patent number: 10038435
    Abstract: In a configuration of an isolation circuit using a transformer of a high-frequency-isolation gate driver circuit in the frequency band from 1 to 100 MHz, a period for resetting the exciting current is eliminated, generation of self-resonance phenomenon after resetting is cancelled to reduce generation of noise current, and malfunctions of the switching element due to noise is prevented. In driving plural gate circuits by RF signals, exciting current is allowed to pass through a primary coil of a gate driver transformer alternately in both directions continuously all the time, in a configuration for isolating drive input signals by the gate driver transformer. Accordingly, the reset period that is required when the exciting current flows only in one way becomes unnecessary, and thus generation of self-resonance phenomenon after resetting is canceled. Then, generation of noise current caused by the self-resonance phenomenon is reduced.
    Type: Grant
    Filed: February 20, 2015
    Date of Patent: July 31, 2018
    Assignee: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Hiroshi Kunitama
  • Publication number: 20170331471
    Abstract: In a configuration of an isolation circuit using a transformer of a high-frequency-isolation gate driver circuit in the frequency band from 1 to 100 MHz, a period for resetting the exciting current is eliminated, generation of self-resonance phenomenon after resetting is cancelled to reduce generation of noise current, and malfunctions of the switching element due to noise is prevented. In driving plural gate circuits by RF signals, exciting current is allowed to pass through a primary coil of a gate driver transformer alternately in both directions continuously all the time, in a configuration for isolating drive input signals by the gate driver transformer. Accordingly, the reset period that is required when the exciting current flows only in one way becomes unnecessary, and thus generation of self-resonance phenomenon after resetting is canceled. Then, generation of noise current caused by the self-resonance phenomenon is reduced.
    Type: Application
    Filed: February 20, 2015
    Publication date: November 16, 2017
    Applicant: KYOSAN ELECTRIC MFG. CO., LTD.
    Inventors: Itsuo Yuzurihara, Hiroshi Kunitama