Patents by Inventor Norikazu Tsukahara

Norikazu Tsukahara 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: 10334694
    Abstract: A light emission control circuit includes a drive circuit that generates a first control signal in order to control a first switching element, and a switching control circuit that generates a second control signal in order to control a second switching element. The switching control circuit maintains the second control signal in an inactivation state in a period in which the first control signal is inactivated in a case where an ON duty ratio of the first control signal is equal to or more than a predetermined value, and maintains the second control signal in an activation state in a part of the period in which the first control signal is inactivated in a case where the ON duty ratio of the first control signal is less than the predetermined value.
    Type: Grant
    Filed: October 4, 2018
    Date of Patent: June 25, 2019
    Assignee: SEIKO EPSON CORPORATION
    Inventors: Norikazu Tsukahara, Atsushi Yamada, Kei Ishimaru
  • Publication number: 20190110349
    Abstract: A light emission control circuit includes a drive circuit that generates a first control signal in order to control a first switching element, and a switching control circuit that generates a second control signal in order to control a second switching element. The switching control circuit maintains the second control signal in an inactivation state in a period in which the first control signal is inactivated in a case where an ON duty ratio of the first control signal is equal to or more than a predetermined value, and maintains the second control signal in an activation state in a part of the period in which the first control signal is inactivated in a case where the ON duty ratio of the first control signal is less than the predetermined value.
    Type: Application
    Filed: October 4, 2018
    Publication date: April 11, 2019
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Norikazu TSUKAHARA, Atsushi YAMADA, Kei ISHIMARU
  • Publication number: 20180307131
    Abstract: This light emission control circuit controls a first switching element for controlling a current that flows to a light-emitting element connected between a first node and one end of an inductor, and a second switching element for controlling a current that flows from the other end of the inductor to a second node. The light emission control circuit has a driving circuit that generates a first control signal for controlling the first switching element, and a switching control circuit that generate a second control signal for controlling the second switching element, and deactivates the second control signal in order to bring the second switching element into an off-state, during a period during which the first switching element is in an off-state.
    Type: Application
    Filed: June 28, 2018
    Publication date: October 25, 2018
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Atsushi YAMADA, Norikazu TSUKAHARA, Kei ISHIMARU
  • Patent number: 10036945
    Abstract: This light emission control circuit controls a first switching element for controlling a current that flows to a light-emitting element connected between a first node and one end of an inductor, and a second switching element for controlling a current that flows from the other end of the inductor to a second node. The light emission control circuit has a driving circuit that generates a first control signal for controlling the first switching element, and a switching control circuit that generate a second control signal for controlling the second switching element, and deactivates the second control signal in order to bring the second switching element into an off-state, during a period during which the first switching element is in an off-state.
    Type: Grant
    Filed: December 13, 2017
    Date of Patent: July 31, 2018
    Assignee: SEIKO EPSON CORPORATION
    Inventors: Atsushi Yamada, Norikazu Tsukahara, Kei Ishimaru
  • Publication number: 20180180978
    Abstract: This light emission control circuit controls a first switching element for controlling a current that flows to a light-emitting element connected between a first node and one end of an inductor, and a second switching element for controlling a current that flows from the other end of the inductor to a second node. The light emission control circuit has a driving circuit that generates a first control signal for controlling the first switching element, and a switching control circuit that generate a second control signal for controlling the second switching element, and deactivates the second control signal in order to bring the second switching element into an off-state, during a period during which the first switching element is in an off-state.
    Type: Application
    Filed: December 13, 2017
    Publication date: June 28, 2018
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Atsushi YAMADA, Norikazu TSUKAHARA, Kei ISHIMARU
  • Patent number: 9985697
    Abstract: A circuit device includes a driver that performs drive control of a resonant circuit and a signal output unit having an input node NAIN to which a resonance signal (AIN) from the resonant circuit is input, an output node NAOUT that outputs an output signal (AOUT) that is based on the resonance signal and a switch element that is provided between the input node NAIN and the output node NAOUT, the driver controlling at least one of a first drive current in an ON period of the switch element and a second drive current in an OFF period of the switch element.
    Type: Grant
    Filed: September 2, 2016
    Date of Patent: May 29, 2018
    Assignee: SEIKO EPSON CORPORATION
    Inventor: Norikazu Tsukahara
  • Publication number: 20170077822
    Abstract: A circuit device includes a driver that performs drive control of a resonant circuit and a signal output unit having an input node NAIN to which a resonance signal (AIN) from the resonant circuit is input, an output node NAOUT that outputs an output signal (AOUT) that is based on the resonance signal and a switch element that is provided between the input node NAIN and the output node NAOUT, the driver controlling at least one of a first drive current in an ON period of the switch element and a second drive current in an OFF period of the switch element.
    Type: Application
    Filed: September 2, 2016
    Publication date: March 16, 2017
    Applicant: SEIKO EPSON CORPORATION
    Inventor: Norikazu TSUKAHARA
  • Patent number: 8258771
    Abstract: A circuit device includes: a power supply circuit; and a logic circuit, the power supply circuit supplying a first power supply voltage and a second power supply voltage to the logic circuit, the first power supply voltage supplied by the power supply circuit periodically changing with a first reference voltage as a reference voltage, the second power supply voltage supplied by the power supply circuit periodically changing with a second reference voltage as a reference voltage, the power supply circuit supplying, due to resonance, the first power supply voltage and the second power supply voltage that repeat a first period during which a voltage difference between the first power supply voltage and the second power supply voltage is decreasing and a second period during which the voltage difference is increasing, and the logic circuit performing adiabatic circuit operation with the supply of the first and the second power supply voltage.
    Type: Grant
    Filed: October 28, 2010
    Date of Patent: September 4, 2012
    Assignee: Seiko Epson Corporation
    Inventors: Hisao Sato, Atsushi Yamada, Norikazu Tsukahara, Toshikazu Kuwano, Yasuhiro Takahashi
  • Publication number: 20110121813
    Abstract: A circuit device includes: a power supply circuit; and a logic circuit, the power supply circuit supplying a first power supply voltage and a second power supply voltage to the logic circuit, the first power supply voltage supplied by the power supply circuit periodically changing with a first reference voltage as a reference voltage, the second power supply voltage supplied by the power supply circuit periodically changing with a second reference voltage as a reference voltage, the power supply circuit supplying, due to resonance, the first power supply voltage and the second power supply voltage that repeat a first period during which a voltage difference between the first power supply voltage and the second power supply voltage is decreasing and a second period during which the voltage difference is increasing, and the logic circuit performing adiabatic circuit operation with the supply of the first and the second power supply voltage.
    Type: Application
    Filed: October 28, 2010
    Publication date: May 26, 2011
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Hisao SATO, Atsushi YAMADA, Norikazu TSUKAHARA, Toshikazu KUWANO, Yasuhiro TAKAHASHI