Patents by Inventor Kei ISHIMARU

Kei ISHIMARU 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: 11761991
    Abstract: A current detection circuit includes an operational amplifier, a current sense amplifier including a first resistor and a second resistor, and a level shifter. The first resistor is provided between one end of a shunt resistor and a first input node of the operational amplifier. The second resistor is provided between the other end of the shunt resistor and a second input node of the operational amplifier. The level shifter controls voltages of the first input node and the second input node by controlling, according to a voltage at the one end of the shunt resistor, currents supplied to the first input node and the second input node.
    Type: Grant
    Filed: March 29, 2022
    Date of Patent: September 19, 2023
    Inventors: Toshimichi Yamada, Kei Ishimaru
  • Patent number: 11749684
    Abstract: A circuit device includes an N-type well on a P-type substrate, a P-type well provided in the N-type well, a circuit element provided in the P-type well, a P-type well provided in an N-type well, and a circuit element provided in the P-type well. A ground power supply voltage is supplied to a P-type well. A power supply voltage different from the ground power supply voltage is supplied to a P-type well. The ground power supply voltage or a first potential that is greater than or equal to the potential of the ground power supply voltage and less than the potential of a high potential-side power supply voltage is supplied to an N-type well.
    Type: Grant
    Filed: July 30, 2020
    Date of Patent: September 5, 2023
    Inventors: Kei Ishimaru, Atsushi Yamada
  • Publication number: 20230268109
    Abstract: A current sense amplifier circuit of a circuit device includes: an operational amplifier; a first resistor provided between one end of a shunt resistor and a first node, a first switch provided between the first node and a first input node, a second resistor provided between another end of the shunt resistor and a second node, a second switch provided between the second node and a second input node, a third resistor provided between a constant voltage node and the third node, a third switch provided between the third node and the first input node, a fourth resistor provided between the constant voltage node and a fourth node, and a fourth switch provided between the fourth node and the second input node.
    Type: Application
    Filed: February 17, 2023
    Publication date: August 24, 2023
    Inventors: Kei ISHIMARU, Yoshihiko NIMURA
  • Patent number: 11632831
    Abstract: The integrated circuit device includes a drive circuit and a regulator. The drive circuit outputs a drive signal to a switching element. A source power supply voltage the same in potential as a source voltage of a transistor as the switching element is input to the regulator, and the regulator generates a gate power supply voltage based on the source power supply voltage. The drive circuit has a level shifter for level-shifting a PWM signal based on the gate power supply voltage and the source power supply voltage. The drive circuit outputs the drive signal based on an output signal of the level shifter to the gate of the transistor.
    Type: Grant
    Filed: January 24, 2022
    Date of Patent: April 18, 2023
    Inventor: Kei Ishimaru
  • Publication number: 20220317162
    Abstract: A current detection circuit includes an operational amplifier, a current sense amplifier including a first resistor and a second resistor, and a level shifter. The first resistor is provided between one end of a shunt resistor and a first input node of the operational amplifier. The second resistor is provided between the other end of the shunt resistor and a second input node of the operational amplifier. The level shifter controls voltages of the first input node and the second input node by controlling, according to a voltage at the one end of the shunt resistor, currents supplied to the first input node and the second input node.
    Type: Application
    Filed: March 29, 2022
    Publication date: October 6, 2022
    Inventors: Toshimichi YAMADA, Kei ISHIMARU
  • Publication number: 20220240357
    Abstract: The integrated circuit device includes a drive circuit and a regulator. The drive circuit outputs a drive signal to a switching element. A source power supply voltage the same in potential as a source voltage of a transistor as the switching element is input to the regulator, and the regulator generates a gate power supply voltage based on the source power supply voltage. The drive circuit has a level shifter for level-shifting a PWM signal based on the gate power supply voltage and the source power supply voltage. The drive circuit outputs the drive signal based on an output signal of the level shifter to the gate of the transistor.
    Type: Application
    Filed: January 24, 2022
    Publication date: July 28, 2022
    Inventor: Kei ISHIMARU
  • Patent number: 11324100
    Abstract: Provided is a light source apparatus including semiconductor light sources and a current detection resistor connected in series, a power source circuit that allows current to flow thereto, a current detection circuit that detects current flowing to the current detection resistor and outputs a current detection signal, a control circuit that controls the power source circuit such that a voltage of the current detection signal approaches a target value, a bypass circuit connected in parallel to the semiconductor light sources, and including a clamp element having a clamp voltage higher than a maximum voltage during operation of the semiconductor light sources and a bypass resistor connected in series to the clamp element, and allowing current to flow when an open fault occurs in the semiconductor light sources, and detection circuits that respectively detect an open fault in the semiconductor light sources based on an end-to-end voltage of the bypass resistors.
    Type: Grant
    Filed: August 27, 2020
    Date of Patent: May 3, 2022
    Assignee: SEIKO EPSON CORPORATION
    Inventors: Kei Ishimaru, Atsushi Yamada
  • Publication number: 20210035491
    Abstract: A circuit device includes an N-type well on a P-type substrate, a P-type well provided in the N-type well, a circuit element provided in the P-type well, a P-type well provided in an N-type well, and a circuit element provided in the P-type well. A ground power supply voltage is supplied to a P-type well. A power supply voltage different from the ground power supply voltage is supplied to a P-type well. The ground power supply voltage or a first potential that is greater than or equal to the potential of the ground power supply voltage and less than the potential of a high potential-side power supply voltage is supplied to an N-type well.
    Type: Application
    Filed: July 30, 2020
    Publication date: February 4, 2021
    Inventors: Kei ISHIMARU, Atsushi YAMADA
  • Publication number: 20200413523
    Abstract: Provided is a light source apparatus including semiconductor light sources and a current detection resistor connected in series, a power source circuit that allows current to flow thereto, a current detection circuit that detects current flowing to the current detection resistor and outputs a current detection signal, a control circuit that controls the power source circuit such that a voltage of the current detection signal approaches a target value, a bypass circuit connected in parallel to the semiconductor light sources, and including a clamp element having a clamp voltage higher than a maximum voltage during operation of the semiconductor light sources and a bypass resistor connected in series to the clamp element, and allowing current to flow when an open fault occurs in the semiconductor light sources, and detection circuits that respectively detect an open fault in the semiconductor light sources based on an end-to-end voltage of the bypass resistors.
    Type: Application
    Filed: August 27, 2020
    Publication date: December 31, 2020
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Kei ISHIMARU, Atsushi YAMADA
  • Patent number: 10795251
    Abstract: The light emission control device includes a PWM terminal to which a PWM signal is input, a first drive circuit for outputting a first control signal, a second drive circuit for outputting a second control signal, and a mode judgment circuit. The first control signal sets the first switching element to an ON state when the PWM signal is in an active state, and sets the first switching element to an OFF state when the PWM signal is in an inactive state. The second control signal controls an ON/OFF state of the second switching element when the PWM signal is in the active state. The mode judgment circuit judges between a PWM dimming mode and an analog dimming mode based on the PWM signal.
    Type: Grant
    Filed: February 19, 2020
    Date of Patent: October 6, 2020
    Assignee: SEIKO EPSON CORPORATION
    Inventor: Kei Ishimaru
  • Publication number: 20200264501
    Abstract: The light emission control device includes a PWM terminal to which a PWM signal is input, a first drive circuit for outputting a first control signal, a second drive circuit for outputting a second control signal, and a mode judgment circuit. The first control signal sets the first switching element to an ON state when the PWM signal is in an active state, and sets the first switching element to an OFF state when the PWM signal is in an inactive state. The second control signal controls an ON/OFF state of the second switching element when the PWM signal is in the active state. The mode judgment circuit judges between a PWM dimming mode and an analog dimming mode based on the PWM signal.
    Type: Application
    Filed: February 19, 2020
    Publication date: August 20, 2020
    Applicant: SEIKO EPSON CORPORATION
    Inventor: Kei ISHIMARU
  • 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