Patents by Inventor Takeshi Togawa
Takeshi Togawa 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: 11245368Abstract: A class D amplifier includes a self-oscillating class D amplification circuit that is driven by an output current signal; and a voltage-current converting circuit that outputs an output current signal in response to an input signal voltage and an output signal voltage from a feedback signal voltage.Type: GrantFiled: March 25, 2019Date of Patent: February 8, 2022Assignee: Yamaha CorporationInventors: Takeshi Togawa, Masao Noro
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Patent number: 11101779Abstract: An amplifying device includes a self-excited class D amplifier circuit and a band elimination filter. The self-excited class D amplifier circuit includes a modulation circuit that is configured to apply self-oscillating pulse modulation to an audio signal. The modulation circuit is configured to receive, from a signal generation circuit, a supply of a synchronizing signal with which the self-oscillation synchronizes. The band elimination filter is configured to reduce components that belong to a frequency band including a frequency of the synchronizing signal, in an output signal from the self-excited class D amplifier circuit.Type: GrantFiled: December 19, 2019Date of Patent: August 24, 2021Assignee: Yamaha CorporationInventor: Takeshi Togawa
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Patent number: 10978998Abstract: An amplifying device includes a first amplifier, a voltage-limiting circuit, a second amplifier, a first controller, and a second controller. The first amplifier is configured to amplify an input signal. The voltage-limiting circuit is configured to limit a voltage of an output signal from the first amplifier to within a limit range. The second amplifier is configured to amplify an output signal from the voltage-limiting circuit. The first controller is configured to control the limit range in accordance with a current supplied to a load from the second amplifier. The second controller is configured to decrease an amplification factor of the first amplifier in a state in which the voltage-limiting circuit limits the voltage of the output signal from the first amplifier.Type: GrantFiled: December 19, 2019Date of Patent: April 13, 2021Assignee: Yamaha CorporationInventor: Takeshi Togawa
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Publication number: 20200127621Abstract: An amplifying device includes a self-excited class D amplifier circuit and a band elimination filter. The self-excited class D amplifier circuit includes a modulation circuit that is configured to apply self-oscillating pulse modulation to an audio signal. The modulation circuit is configured to receive, from a signal generation circuit, a supply of a synchronizing signal with which the self-oscillation synchronizes. The band elimination filter is configured to reduce components that belong to a frequency band including a frequency of the synchronizing signal, in an output signal from the self-excited class D amplifier circuit.Type: ApplicationFiled: December 19, 2019Publication date: April 23, 2020Inventor: Takeshi TOGAWA
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Publication number: 20200127606Abstract: An amplifying device includes a first amplifier, a voltage-limiting circuit, a second amplifier, a first controller, and a second controller. The first amplifier is configured to amplify an input signal. The voltage-limiting circuit is configured to limit a voltage of an output signal from the first amplifier to within a limit range. The second amplifier is configured to amplify an output signal from the voltage-limiting circuit. The first controller is configured to control the limit range in accordance with a current supplied to a load from the second amplifier. The second controller is configured to decrease an amplification factor of the first amplifier in a state in which the voltage-limiting circuit limits the voltage of the output signal from the first amplifier.Type: ApplicationFiled: December 19, 2019Publication date: April 23, 2020Inventor: Takeshi TOGAWA
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Publication number: 20190222182Abstract: A class D amplifier includes a self-oscillating class D amplification circuit that is driven by an output current signal; and a voltage-current converting circuit that outputs an output current signal in response to an input signal voltage and an output signal voltage from a feedback signal voltage.Type: ApplicationFiled: March 25, 2019Publication date: July 18, 2019Inventors: Takeshi TOGAWA, Masao NORO
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Patent number: 10038416Abstract: A self-oscillating class D amplifier includes an integration circuit configured to integrate an input signal and output a result of the integration as an integrated signal, a comparator configured to receive the integrated signal at an inverting input terminal and output a pulse width modulation signal by comparing voltages of a non-inverting input terminal being grounded and the inverting input terminal, a switching circuit configured to power-amplify the pulse width modulation signal output from the comparator, a low-pass filter configured to extract an amplified output signal from the power-amplified pulse width modulation signal, a first feedback circuit configured to feed back the output signal of the low-pass filter to the inverting input terminal of the comparator, and a second feedback circuit configured to feed back the output signal of the low-pass filter to the integration circuit.Type: GrantFiled: March 24, 2017Date of Patent: July 31, 2018Assignee: YAMAHA CORPORATIONInventors: Takeshi Togawa, Masao Noro
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Publication number: 20170279421Abstract: A self-oscillating class D amplifier includes an integration circuit configured to integrate an input signal and output a result of the integration as an integrated signal, a comparator configured to receive the integrated signal at an inverting input terminal and output a pulse width modulation signal by comparing voltages of a non-inverting input terminal being grounded and the inverting input terminal, a switching circuit configured to power-amplify the pulse width modulation signal output from the comparator, a low-pass filter configured to extract an amplified output signal from the power-amplified pulse width modulation signal, a first feedback circuit configured to feed back the output signal of the low-pass filter to the inverting input terminal of the comparator, and a second feedback circuit configured to feed back the output signal of the low-pass filter to the integration circuit.Type: ApplicationFiled: March 24, 2017Publication date: September 28, 2017Inventors: Takeshi TOGAWA, Masao NORO
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Publication number: 20170279422Abstract: A Bridge-Tied Load output self-oscillating class D amplifier includes a comparator receives an input signal from a signal input circuit at a second input terminal and outputs a positive-phase pulse width modulation signal and a reverse-phase pulse width modulation signal by comparing voltages of the two input terminal, first and second switching circuits power-amplifies the reverse-phase pulse width modulation signal and the positive-phase pulse width modulation signal, a first low-pass filter extracts a first output signal from the reverse-phase pulse width modulation signal, a second low-pass filter extracts a second output signal from the positive-phase pulse width modulation signal, a subtractor calculates a difference between the first and second output signals and output a difference signal, and a first feedback circuit feeds back the difference signal to the second input terminal of the comparator.Type: ApplicationFiled: March 24, 2017Publication date: September 28, 2017Inventors: Takeshi TOGAWA, Masao NORO
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Patent number: 9634623Abstract: The invention is provided with a first class-D amplifying unit for amplifying an inputted audio signal and supplying the amplified signal to a positive side of an audio output terminal, a second class-D amplifying unit for amplifying an inputted audio signal inverted in an inverting unit and supplying the amplified signal to a negative side of the audio output terminal, wherein, in a first mode, the first and second class-D amplifying units are activated and outputs of the first and second class-D amplifying units are kept equal to or less than a first current value, and wherein, in a second mode, the first class-D amplifying unit is activated, the second class-D amplifying unit is inactivated, the negative side of the audio output terminal is grounded, and output of the first class-D amplifying unit is kept equal to or less than a second current value larger than the first current value.Type: GrantFiled: June 20, 2014Date of Patent: April 25, 2017Assignee: Yamaha CorporationInventor: Takeshi Togawa
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Publication number: 20140301577Abstract: The invention is provided with a first class-D amplifying unit for amplifying an inputted audio signal and supplying the amplified signal to a positive side of an audio output terminal, a second class-D amplifying unit for amplifying an inputted audio signal inverted in an inverting unit and supplying the amplified signal to a negative side of the audio output terminal, wherein, in a first mode, the first and second class-D amplifying units are activated and outputs of the first and second class-D amplifying units are kept equal to or less than a first current value, and wherein, in a second mode, the first class-D amplifying unit is activated, the second class-D amplifying unit is inactivated, the negative side of the audio output terminal is grounded, and output of the first class-D amplifying unit is kept equal to or less than a second current value larger than the first current value.Type: ApplicationFiled: June 20, 2014Publication date: October 9, 2014Inventor: Takeshi TOGAWA
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Patent number: 8618881Abstract: A class-D power amplifier includes a switching power source section, a synchronization signal generation section and a class-D power amplifying section. The synchronization signal generation section takes out of the switching power source section a clock signal having a second frequency which is ānā times of a first frequency. The class-D power amplifying section includes a comparator which compares an input signal with a feedback signal, a second switching section which switches a power source fed from the synchronization signal generation section, a filter section which smoothes an output signal from the second switching section, and a combining section which combines a delayed output signal with a clock signal from the synchronization signal generation section to generate the feedback signal.Type: GrantFiled: March 17, 2011Date of Patent: December 31, 2013Assignee: Yamaha CorporationInventors: Toshiro Mayuzumi, Takeshi Togawa
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Publication number: 20110227645Abstract: A class-D power amplifier includes a switching power source section, a synchronization signal generation section and a class-D power amplifying section. The synchronization signal generation section takes out of the switching power source section a clock signal having a second frequency which is ānā times of a first frequency. The class-D power amplifying section includes a comparator which compares an input signal with a feedback signal, a second switching section which switches a power source fed from the synchronization signal generation section, a filter section which smoothes an output signal from the second switching section, and a combining section which combines a delayed output signal with a clock signal from the synchronization signal generation section to generate the feedback signal.Type: ApplicationFiled: March 17, 2011Publication date: September 22, 2011Applicant: Yamaha CorporationInventors: Toshiro MAYUZUMI, Takeshi TOGAWA
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Patent number: 6103736Abstract: Compounds of the formula: ##STR1## which are useful as anti-ulcer agent are provided.Type: GrantFiled: June 29, 1999Date of Patent: August 15, 2000Assignee: Shinnippon Pharmaceutical Inc.Inventors: Hironori Tanaka, Kazuyoshi Fukuzumi, Takeshi Togawa, Kimiko Banno, Toshihisa Ushiro, Masaaki Morii, Takafumi Nakatani
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Patent number: 6020342Abstract: Compounds of the formula: ##STR1## which are useful as anti-ulcer agent are provided.Type: GrantFiled: October 21, 1997Date of Patent: February 1, 2000Assignee: Shinnippon Pharmaceutical, Inc.Inventors: Hironori Tanaka, Kazuyoshi Fukuzumi, Takeshi Togawa, Kimiko Banno, Toshihisa Ushiro, Masaaki Morii, Takafumi Nakatani