Patents by Inventor Naotaka Tomita

Naotaka Tomita 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: 10116266
    Abstract: A Doherty amplifier of an embodiment includes an input terminal, an output terminal a splitter, a combiner, a carrier amplifier, a peak amplifier. The splitter is connected to the input terminal, the splitter having first and second outputs. The combiner is connected to the output terminal, the combiner having first and second inputs. The carrier amplifier includes a first input-side two-port network connected to the first output of the splitter, a first amplifier connected to an output of the first input-side two-port network, and a first output-side two-port network connected between an output of the first amplifier and the first input of the combiner. The peak amplifier includes a second input-side two-port network connected to the second output of the splitter, a second amplifier connected to the output of the second input-side two-port network, and a second output-side two-port network connected between an output of the second amplifier and the second input of the combiner.
    Type: Grant
    Filed: February 21, 2017
    Date of Patent: October 30, 2018
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kazutaka Takagi, Naotaka Tomita
  • Patent number: 9748904
    Abstract: A high frequency signal amplifying circuitry of an embodiment includes a first splitter, a first amplifier, a second amplifier, a loop oscillation suppressor, and a combiner. The first amplifier includes a second splitter, a first carrier amplifier, a first peak amplifier, and a first combiner. The second amplifier includes a third splitter, a second carrier amplifier, a second peak amplifier, and a second combiner. The second carrier amplifier being adjacent to an associated the first carrier amplifier or the second peak amplifier being adjacent to an associated the first peak amplifier. The loop oscillation suppressor located between the second carrier amplifier and the associated first carrier amplifier or the second peak amplifier and the associated first peak amplifier.
    Type: Grant
    Filed: December 18, 2015
    Date of Patent: August 29, 2017
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kazutaka Takagi, Naotaka Tomita
  • Publication number: 20170163221
    Abstract: A Doherty amplifier of an embodiment includes an input terminal, an output terminal a splitter, a combiner, a carrier amplifier, a peak amplifier. The splitter is connected to the input terminal, the splitter having first and second outputs. The combiner is connected to the output terminal, the combiner having first and second inputs. The carrier amplifier includes a first input-side two-port network connected to the first output of the splitter, a first amplifier connected to an output of the first input-side two-port network, and a first output-side two-port network connected between an output of the first amplifier and the first input of the combiner. The peak amplifier includes a second input-side two-port network connected to the second output of the splitter, a second amplifier connected to the output of the second input-side two-port network, and a second output-side two-port network connected between an output of the second amplifier and the second input of the combiner.
    Type: Application
    Filed: February 21, 2017
    Publication date: June 8, 2017
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kazutaka TAKAGI, Naotaka TOMITA
  • Publication number: 20160204748
    Abstract: A high frequency signal amplifying circuitry of an embodiment includes a first splitter, a first amplifier, a second amplifier, a loop oscillation suppressor, and a combiner. The first amplifier includes a second splitter, a first carrier amplifier, a first peak amplifier, and a first combiner. The second amplifier includes a third splitter, a second carrier amplifier, a second peak amplifier, and a second combiner. The second carrier amplifier being adjacent to an associated the first carrier amplifier or the second peak amplifier being adjacent to an associated the first peak amplifier. The loop oscillation suppressor located between the second carrier amplifier and the associated first carrier amplifier or the second peak amplifier and the associated first peak amplifier.
    Type: Application
    Filed: December 18, 2015
    Publication date: July 14, 2016
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Kazutaka TAKAGI, Naotaka TOMITA
  • Publication number: 20160204747
    Abstract: A Doherty amplifier of an embodiment includes an input terminal, an output terminal a splitter, a combiner, a carrier amplifier, a peak amplifier. The splitter is connected to the input terminal, the splitter having first and second outputs. The combiner is connected to the output terminal, the combiner having first and second inputs. The carrier amplifier includes a first input-side two-port network connected to the first output of the splitter, a first amplifier connected to an output of the first input-side two-port network, and a first output-side two-port network connected between an output of the first amplifier and the first input of the combiner. The peak amplifier includes a second input-side two-port network connected to the second output of the splitter, a second amplifier connected to the output of the second input-side two-port network, and a second output-side two-port network connected between an output of the second amplifier and the second input of the combiner.
    Type: Application
    Filed: December 15, 2015
    Publication date: July 14, 2016
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Kazutaka TAKAGI, Naotaka Tomita
  • Patent number: 8653896
    Abstract: A class-AB power amplifier according to the present embodiment includes an amplifying element whose power supply voltage is expressed as Vdc and whose maximum current is expressed as Imax, a conduction angle ?o of the amplifying element being more than ?(rad) and less than 2·?(rad), and load impedance of a fundamental wave being expressed as Z1=R1+j·X1, load impedance of a 2nd harmonic being expressed as Z2=R2+j·X2, and load impedance of a 3rd harmonic being expressed as Z3=R3+j?X3 which are observed from a dependent current source of an equivalent circuit of the amplifying element, and a relationship between variables X1 and R1 is set to ?0.5·R1<=X1<=0.5·R1, variable R1 is set to R1=Vdc/Imax·{1?cos(?o/2)}·?/{?o/2?sin(?o)/2}, variable X2/X1 is set to X2/X1=?2·{?o?sin(?o)}/{sin(?o/2)?sin(1.5·?o)/3}, and variable X3/X1 is set to X3/X1={?o?sin(?o)}/{sin(?o)/3?sin(2·?o)/6}, or each of the variables is set thereto so as to become equal substantially.
    Type: Grant
    Filed: October 6, 2011
    Date of Patent: February 18, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kazutaka Takagi, Naotaka Tomita
  • Patent number: 8643438
    Abstract: According to an embodiment, a class-AB power amplifier includes an amplifying element whose power supply voltage is expressed as Vdc and whose maximum current is expressed as Imax, a conduction angle ?o of the amplifying element being more than ?(rad) and less than 2·?(rad), and load impedance of a fundamental wave being expressed as Z1=R1+j·X1 and load impedance of a 2nd harmonic being expressed as Z2=R2+j·X2 which are observed from a dependent current source of an equivalent circuit of the amplifying element, wherein a relationship between variables X1 and R1 is set to ?R1<=X1<=R1, variable R1 is set to R1=Vdc/Imax·?·{1?cos(?o/2)}/{?o/2?sin(?o)/2}, and variable X2/X1 is set to X2/X1=?{?o/2?sin(?o)/2}/{sin(?o/2)?sin(1.5·?o)/3}, or each of the variables is set thereto so as to become equal substantially.
    Type: Grant
    Filed: October 6, 2011
    Date of Patent: February 4, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kazutaka Takagi, Naotaka Tomita
  • Patent number: 8604883
    Abstract: According to one embodiment, a class-C power amplifier includes an amplifying element whose power supply voltage is expressed as Vdc and whose maximum current is expressed as Imax, a conduction angle ?o of the amplifying element being less than ?(rad), and load impedance of a fundamental wave being expressed as Z1=R1+j·X1 and load impedance of a 2nd harmonic being expressed as Z2=R2+j·X2 which are observed from a dependent current source of an equivalent circuit of the amplifying element, wherein a relationship between variables X1 and R1 is set to ?R1<=X1<=R1, variable R1 is set to R1=Vdc/Imax·?·{1?cos(?o/2)}/{?o/2?sin(?o)/2}, and variable X2/X1 is set to X2/X1=?{?o/2?sin(?o)/2}/{sin(?/2)?sin(1.5·?o)/3}, or each of the variables is set thereto so as to become equal substantially.
    Type: Grant
    Filed: October 6, 2011
    Date of Patent: December 10, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kazutaka Takagi, Naotaka Tomita
  • Patent number: 8427248
    Abstract: A stabilization network and a semiconductor device having the stabilization network wherein the stabilization network includes an active element having a negative resistance accompanying a high frequency negative resistance oscillation; and a tank circuit composed of a resistance connected to a main electrode of the active element, an inductance and capacitance which are connected in parallel with the resistance and synchronize with an oscillating frequency of the high frequency negative resistance oscillation, wherein the stabilization network is performed for suppressing a negative resistance accompanying a Gunn oscillation and obtaining stable and highly efficient power amplification.
    Type: Grant
    Filed: April 2, 2009
    Date of Patent: April 23, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Choon Yong Ng, Kazutaka Takagi, Naotaka Tomita
  • Patent number: 8405374
    Abstract: A power amplification device configured to switching-amplify a high-frequency input signal and output a switching-amplified signal. The device includes a feedback circuit configured to output a feedback signal including a portion of the switching-amplified signal; a subtractor configured to output an error signal indicating a difference between the input signal and the feedback signal; a comparator configured to compare the error signal with a threshold voltage and generate an on/off pulse signal based on a result of the comparison; a one-shot circuit configured to be set in an on-state for a time period using a rising timing of the pulse signal as a trigger; and an amplifier configured to switching-amplify the input signal by a logical OR between the generated on/off pulse signal and an output signal from the one-shot circuit, and output the switching-amplified signal.
    Type: Grant
    Filed: August 3, 2010
    Date of Patent: March 26, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Naotaka Tomita, Tooru Kijima
  • Publication number: 20120218045
    Abstract: According to one embodiment, a class-C power amplifier includes an amplifying element whose power supply voltage is expressed as Vdc and whose maximum current is expressed as Imax, a conduction angle ?o of the amplifying element being less than ?(rad), and load impedance of a fundamental wave being expressed as Z1=R1+j·X1 and load impedance of a 2nd harmonic being expressed as Z2=R2+j·X2 which are observed from a dependent current source of an equivalent circuit of the amplifying element, wherein a relationship between variables X1 and R1 is set to ?R1<=X1<=R1, variable R1 is set to R1=Vdc/Imax·?·{1?cos(?o/2)}/{?o/2?sin(?o)/2}, and variable X2/X1 is set to X2/X1=?{?o/2?sin(?o)/2}/{sin(?/2)?sin(1.5·?o)/3), or each of the variables is set thereto so as to become equal substantially.
    Type: Application
    Filed: October 6, 2011
    Publication date: August 30, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kazutaka Takagi, Naotaka Tomita
  • Publication number: 20120218046
    Abstract: A class-AB power amplifier according to the present embodiment includes an amplifying element whose power supply voltage is expressed as Vdc and whose maximum current is expressed as Imax, a conduction angle ?o of the amplifying element being more than ?(rad) and less than 2·?(rad), and load impedance of a fundamental wave being expressed as Z1=R1+j·X1, load impedance of a 2nd harmonic being expressed as Z2=R2+j·X2, and load impedance of a 3rd harmonic being expressed as Z3=R3+j?X3 which are observed from a dependent current source of an equivalent circuit of the amplifying element, and a relationship between variables X1 and R1 is set to ?0.5·R1<=X1<=0.5·R1, variable R1 is set to R1=Vdc/Imax·{1?cos(?o/2)}·?/{?o/2?sin(?o)/2}, variable X2/X1 is set to X2/X1=?2·{?o?sin(?o)}/{ sin(?o/2)?sin(1.5·?o)/3}, and variable X3/X1 is set to X3/X1={?o?sin(?o)}/{ sin(?o)/3?sin(2·?o)/6}, or each of the variables is set thereto so as to become equal substantially.
    Type: Application
    Filed: October 6, 2011
    Publication date: August 30, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kazutaka TAKAGI, Naotaka TOMITA
  • Publication number: 20120218040
    Abstract: According to an embodiment, a class-AB power amplifier includes an amplifying element whose power supply voltage is expressed as Vdc and whose maximum current is expressed as Imax, a conduction angle ?o of the amplifying element being more than ?(rad) and less than 2·?r(rad), and load impedance of a fundamental wave being expressed as Z1=R1+j·X1 and load impedance of a 2nd harmonic being expressed as Z2=R2+j·X2 which are observed from a dependent current source of an equivalent circuit of the amplifying element, wherein a relationship between variables X1 and R1 is set to ?R1<=X1<=R1, variable R1 is set to R1=Vdc/Imax·?·{1?cos(?o/2)}/{?o/2?sin(?o)/2}, and variable X2/X1 is set to X2/X1=?{?o/2?sin(?o)/2}/{sin(?o/2)?sin(1.5·?o)/3}, or each of the variables is set thereto so as to become equal substantially.
    Type: Application
    Filed: October 6, 2011
    Publication date: August 30, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kazutaka Takagi, Naotaka Tomita
  • Patent number: 8154079
    Abstract: A semiconductor device, which can prevent an element breakdown by alleviating of electric field concentrations, and can also prevent reduction of gain, includes: a source electrode formed on a semiconductor layer; a drain electrode formed on the semiconductor layer; a gate electrode formed between the source electrode and the drain electrode; an insulating film formed on the semiconductor layer and the gate electrode; a field plate electrode formed on the insulating film; and a resistor for connecting the field plate electrode and the source electrode.
    Type: Grant
    Filed: November 28, 2007
    Date of Patent: April 10, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Keiichi Matsushita, Kazutaka Takagi, Naotaka Tomita
  • Patent number: 8115554
    Abstract: According to one embodiment, there is a semiconductor device including a first active element, a second active element connected in parallel with the first active element, and a first stabilization circuit connected between a gate of the first active element and a gate of the second active element and configured with a parallel circuit of a gate bypass resistor, a gate bypass capacitor, and a gate bypass inductor, the first stabilization circuit having a resonant frequency equal to an odd mode resonant frequency.
    Type: Grant
    Filed: August 17, 2011
    Date of Patent: February 14, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Choon Young Ng, Kazutaka Takagi, Naotaka Tomita
  • Publication number: 20110298552
    Abstract: According to one embodiment, there is a semiconductor device including a first active element, a second active element connected in parallel with the first active element, and a first stabilization circuit connected between a gate of the first active element and a gate of the second active element and configured with a parallel circuit of a gate bypass resistor, a gate bypass capacitor, and a gate bypass inductor, the first stabilization circuit having a resonant frequency equal to an odd mode resonant frequency.
    Type: Application
    Filed: August 17, 2011
    Publication date: December 8, 2011
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Choon Young NG, Kazutaka Takagi, Naotaka Tomita
  • Patent number: 8022769
    Abstract: According to one embodiment, there is a semiconductor device including a first active element, a second active element connected in parallel with the first active element, and a first stabilization circuit connected between a gate of the first active element and a gate of the second active element and configured with a parallel circuit of a gate bypass resistor, a gate bypass capacitor, and a gate bypass inductor, the first stabilization circuit having a resonant frequency equal to an odd mode resonant frequency.
    Type: Grant
    Filed: May 14, 2010
    Date of Patent: September 20, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Choon Yong Ng, Kazutaka Takagi, Naotaka Tomita
  • Publication number: 20110089921
    Abstract: According to one embodiment, a power amplification device configured to switching-amplify a high-frequency input signal into an output signal includes a feedback circuit, a subtractor, a comparator, an output tuning circuit, a constant voltage controlled power supply, and an amplifier. The feedback circuit is configured to output a portion of the output signal as a feedback signal. The subtractor is configured to output a difference between the input signal and the feedback signal as a error signal. The comparator is configured to generate an on/off pulse signal by comparing the error signal with a predetermined threshold voltage. The output tuning circuit is configured to resonate to a frequency of the input signal. The amplifier is configured to generate the output signal by switching-amplifying the input signal according to on/off of pulse signal, and output the output signal to the output tuning circuit.
    Type: Application
    Filed: August 3, 2010
    Publication date: April 21, 2011
    Inventors: Naotaka TOMITA, Tooru KIJIMA
  • Publication number: 20110018631
    Abstract: According to one embodiment, there is a semiconductor device including a first active element, a second active element connected in parallel with the first active element, and a first stabilization circuit connected between a gate of the first active element and a gate of the second active element and configured with a parallel circuit of a gate bypass resistor, a gate bypass capacitor, and a gate bypass inductor, the first stabilization circuit having a resonant frequency equal to an odd mode resonant frequency.
    Type: Application
    Filed: May 14, 2010
    Publication date: January 27, 2011
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Choon Yong Ng, Kazutaka Takagi, Naotaka Tomita
  • Publication number: 20100073099
    Abstract: A stabilization network and a semiconductor device having the stabilization network wherein the stabilization network includes an active element having a negative resistance accompanying a high frequency negative resistance oscillation; and a tank circuit composed of a resistance connected to a main electrode of the active element, an inductance and capacitance which are connected in parallel with the resistance and synchronize with an oscillating frequency of the high frequency negative resistance oscillation, wherein the stabilization network is performed for suppressing a negative resistance accompanying a Gunn oscillation and obtaining stable and highly efficient power amplification.
    Type: Application
    Filed: April 2, 2009
    Publication date: March 25, 2010
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Choon Yong NG, Kazutaka Takagi, Naotaka Tomita