Patents by Inventor Masatoshi Yokai

Masatoshi Yokai 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: 8310194
    Abstract: A load drive device for driving an inductive load by PWM controlling a switching element includes synchronization control unit, a synchronization signal input terminal, and a synchronization signal output terminal. The synchronization control unit outputs the PWM signal to the switching element. The synchronization control unit receives a synchronization signal through the input terminal from an exterior. The synchronization control unit outputs the synchronization signal through the output terminal to an exterior. When the synchronization control unit does not receive the synchronization signal, the synchronization control unit outputs the synchronization signal such that a first switching period of the PWM signal is prevented from overlapping with a second switching period of a PWM signal of an external device. When the synchronization control unit receives the synchronization signal, the synchronization control unit generates the PWM signal based on the synchronization signal.
    Type: Grant
    Filed: July 28, 2009
    Date of Patent: November 13, 2012
    Assignee: DENSO CORPORATION
    Inventors: Masatoshi Yokai, Satoshi Yoshimura, Kouji Nakamura, Masao Yamada
  • Patent number: 7852026
    Abstract: A protection circuit is configured to change control modes in a drive control process of a drive circuit for a motor when overvoltage is applied to a power source line while the motor is driven. With overvoltage applied, the control process is changed to a control mode to perform forced commutation control. When a predetermined time period passes after the voltage of the power source line returns to a predetermined level, the control process is changed to a sensorless control mode using a position detection circuit. This configuration can provide a motor drive apparatus capable of performing an overvoltage protection operation appropriately even when the sensorless control mode is adopted.
    Type: Grant
    Filed: May 20, 2008
    Date of Patent: December 14, 2010
    Assignee: DENSO CORPORATION
    Inventors: Masatoshi Yokai, Atsushi Kanamori
  • Publication number: 20100026355
    Abstract: A load drive device for driving an inductive load by PWM controlling a switching element includes synchronization control unit, a synchronization signal input terminal, and a synchronization signal output terminal. The synchronization control unit outputs the PWM signal to the switching element. The synchronization control unit receives a synchronization signal through the input terminal from an exterior. The synchronization control unit outputs the synchronization signal through the output terminal to an exterior. When the synchronization control unit does not receive the synchronization signal, the synchronization control unit outputs the synchronization signal such that a first switching period of the PWM signal is prevented from overlapping with a second switching period of a PWM signal of an external device. When the synchronization control unit receives the synchronization signal, the synchronization control unit generates the PWM signal based on the synchronization signal.
    Type: Application
    Filed: July 28, 2009
    Publication date: February 4, 2010
    Applicant: DENSO CORPORATION
    Inventors: Masatoshi Yokai, Satoshi Yoshimura, Kouji Nakamura, Masao Yamada
  • Publication number: 20080291589
    Abstract: A protection circuit is configured to change control modes in a drive control process of a drive circuit for a motor when overvoltage is applied to a power source line while the motor is driven. With overvoltage applied, the control process is changed to a control mode to perform forced commutation control. When a predetermined time period passes after the voltage of the power source line returns to a predetermined level, the control process is changed to a sensorless control mode using a position detection circuit. This configuration can provide a motor drive apparatus capable of performing an overvoltage protection operation appropriately even when the sensorless control mode is adopted.
    Type: Application
    Filed: May 20, 2008
    Publication date: November 27, 2008
    Applicant: DENSO CORPORATION
    Inventors: Masatoshi Yokai, Atsushi Kanamori
  • Patent number: 7453679
    Abstract: An inverter apparatus includes an inverter circuit, a temperature sensor, and a control circuit. The inverter circuit is driven by a PWM signal and includes switching elements that are divided in first and second groups. The temperature sensor detects a temperature of at least one of the switching elements of the first group. The control circuit controls a duty cycle of the PWM signal such that a first value of heat generated in the first group is equal to or greater than a second value of heat generated in the second group. The control circuit performs an overheat protection for protecting the inverter circuit from overheating when the detected temperature is equal to or greater than a threshold temperature.
    Type: Grant
    Filed: February 22, 2007
    Date of Patent: November 18, 2008
    Assignee: Denso Corporation
    Inventors: Masatoshi Yokai, Satoshi Yoshimura, Akira Ando
  • Publication number: 20070201176
    Abstract: An inverter apparatus includes an inverter circuit, a temperature sensor, and a control circuit. The inverter circuit is driven by a PWM signal and includes switching elements that are divided in first and second groups. The temperature sensor detects a temperature of at least one of the switching elements of the first group. The control circuit controls a duty cycle of the PWM signal such that a first value of heat generated in the first group is equal to or greater than a second value of heat generated in the second group. The control circuit performs an overheat protection for protecting the inverter circuit from overheating when the detected temperature is equal to or greater than a threshold temperature.
    Type: Application
    Filed: February 22, 2007
    Publication date: August 30, 2007
    Applicant: DENSO CORPORATION
    Inventors: Masatoshi Yokai, Satoshi Yoshimura, Akira Ando