Patents by Inventor Sadakazu Murakami

Sadakazu Murakami 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).

  • Publication number: 20200321863
    Abstract: A light emitting load driving device includes a first constant current source structured to be serially connected to a first light emitting load group; a second constant current source structured to be serially connected to a second light emitting load group; a first load connection terminal structured to be connected to the first light emitting load group; a second load connection terminal structured to be connected to the second light emitting load group; and a control circuit structured to be supplied a first voltage applied to the first load connection terminal, a second voltage applied to the second load connection terminal, and a reference voltage applied to the control circuit, wherein the control circuit is structured to select a minimum voltage between the first voltage and the second voltage, and the control circuit is structured to equalize the minimum voltage and the reference voltage.
    Type: Application
    Filed: June 23, 2020
    Publication date: October 8, 2020
    Inventor: Sadakazu Murakami
  • Patent number: 10734896
    Abstract: A light emitting load driving device includes a plurality of constant current sources structured to be serially connected to a plurality of light emitting loads connected in parallel respectively, and structured to control a current flowing through the plurality of light emitting loads connected in parallel; a plurality of load connection terminals structured to be connected to the plurality of light emitting loads connected in parallel and the plurality of constant current sources respectively; a control circuit structured to be controlled based on a plurality of terminal voltage applied to the plurality of load connection terminals and a reference voltage, and structured to control a voltage output portion generating an output voltage provided to the plurality of light emitting loads connected in parallel so that both of a lowest terminal voltage applied to the plurality of load connection terminals and the reference voltage are equalized with respect to each other.
    Type: Grant
    Filed: July 11, 2019
    Date of Patent: August 4, 2020
    Assignee: ROHM Co., LTD.
    Inventor: Sadakazu Murakami
  • Publication number: 20190334437
    Abstract: A light emitting load driving device includes a plurality of constant current sources structured to be serially connected to a plurality of light emitting loads connected in parallel respectively, and structured to control a current flowing through the plurality of light emitting loads connected in parallel; a plurality of load connection terminals structured to be connected to the plurality of light emitting loads connected in parallel and the plurality of constant current sources respectively; a control circuit structured to be controlled based on a plurality of terminal voltage applied to the plurality of load connection terminals and a reference voltage, and structured to control a voltage output portion generating an output voltage provided to the plurality of light emitting loads connected in parallel so that both of a lowest terminal voltage applied to the plurality of load connection terminals and the reference voltage are equalized with respect to each other.
    Type: Application
    Filed: July 11, 2019
    Publication date: October 31, 2019
    Inventor: Sadakazu Murakami
  • Patent number: 10396659
    Abstract: A light emitting load driving device includes a plurality of constant current sources structured to be serially connected to a plurality of light emitting loads connected in parallel respectively, and structured to control a current flowing through the plurality of light emitting loads connected in parallel respective; a plurality of load connection terminals structured to connect the plurality of light emitting loads connected in parallel and the plurality of constant current sources respectively; a signal processing circuit structured to select and compare a lowest terminal voltage applied to the plurality of load connection terminals with a reference voltage, and output a comparison result; and a pulse width modulation control circuit structured to output a drive signal according to the comparison result, and structured to control a voltage output portion generating an output voltage provided to the plurality of light emitting loads connected in parallel respectively.
    Type: Grant
    Filed: September 11, 2018
    Date of Patent: August 27, 2019
    Assignee: Rohm Co., Ltd.
    Inventor: Sadakazu Murakami
  • Publication number: 20190013730
    Abstract: A light emitting load driving device includes a plurality of constant current sources structured to be serially connected to a plurality of light emitting loads connected in parallel respectively, and structured to control a current flowing through the plurality of light emitting loads connected in parallel respective; a plurality of load connection terminals structured to connect the plurality of light emitting loads connected in parallel and the plurality of constant current sources respectively; a signal processing circuit structured to select and compare a lowest terminal voltage applied to the plurality of load connection terminals with a reference voltage, and output a comparison result; and a pulse width modulation control circuit structured to output a drive signal according to the comparison result, and structured to control a voltage output portion generating an output voltage provided to the plurality of light emitting loads connected in parallele respectively.
    Type: Application
    Filed: September 11, 2018
    Publication date: January 10, 2019
    Inventor: Sadakazu Murakami
  • Patent number: 10103625
    Abstract: A light emitting load driving device includes a plurality of constant current sources structured to be serially connected to a plurality of light emitting loads connected in parallel respectively, and structured to control a current flowing through the plurality of light emitting loads connected in parallel respective; a plurality of load connection terminals structured to connect the plurality of light emitting loads connected in parallel and the plurality of constant current sources respectively; a signal processing circuit structured to select and compare a lowest terminal voltage applied to the plurality of load connection terminals with a reference voltage, and output a comparison result; and a pulse width modulation control circuit structured to output a drive signal according to the comparison result, and structured to control a voltage output portion generating an output voltage provided to the plurality of light emitting loads connected in parallele respectively.
    Type: Grant
    Filed: March 19, 2018
    Date of Patent: October 16, 2018
    Assignee: Rohm Co., Ltd.
    Inventor: Sadakazu Murakami
  • Publication number: 20180212518
    Abstract: A light emitting load driving device includes a plurality of constant current sources structured to be serially connected to a plurality of light emitting loads connected in parallel respectively, and structured to control a current flowing through the plurality of light emitting loads connected in parallel respective; a plurality of load connection terminals structured to connect the plurality of light emitting loads connected in parallel and the plurality of constant current sources respectively; a signal processing circuit structured to select and compare a lowest terminal voltage applied to the plurality of load connection terminals with a reference voltage, and output a comparison result; and a pulse width modulation control circuit structured to output a drive signal according to the comparison result, and structured to control a voltage output portion generating an output voltage provided to the plurality of light emitting loads connected in parallele respectively.
    Type: Application
    Filed: March 19, 2018
    Publication date: July 26, 2018
    Inventor: Sadakazu Murakami
  • Patent number: 9960677
    Abstract: A load driving device disclosed in the specification includes a power supply circuit for supplying to a load an output voltage converted from an input voltage, a detection voltage generation circuit for generating a detection voltage which varies depending on a magnitude of a voltage drop which across the load, and a control circuit for controlling the power supply circuit so that it performs output feedback control of the output voltage, on the basis of the detection voltage.
    Type: Grant
    Filed: November 10, 2016
    Date of Patent: May 1, 2018
    Assignee: ROHM CO., LTD.
    Inventor: Sadakazu Murakami
  • Publication number: 20170063226
    Abstract: A load driving device disclosed in the specification includes a power supply circuit for supplying to a load an output voltage converted from an input voltage, a detection voltage generation circuit for generating a detection voltage which varies depending on a magnitude of a voltage drop which across the load, and a control circuit for controlling the power supply circuit so that it performs output feedback control of the output voltage, on the basis of the detection voltage.
    Type: Application
    Filed: November 10, 2016
    Publication date: March 2, 2017
    Applicant: ROHM CO., LTD.
    Inventor: Sadakazu MURAKAMI
  • Patent number: 9526138
    Abstract: A load driving device disclosed in the specification includes a power supply circuit for supplying to a load an output voltage converted from an input voltage, a detection voltage generation circuit for generating a detection voltage which varies depending on a magnitude of a voltage drop which across the load, and a control circuit for controlling the power supply circuit so that it performs output feedback control of the output voltage, on the basis of the detection voltage.
    Type: Grant
    Filed: August 7, 2014
    Date of Patent: December 20, 2016
    Assignee: ROHM CO., LTD.
    Inventor: Sadakazu Murakami
  • Patent number: 9526139
    Abstract: A load driving device disclosed in the specification includes a power supply circuit for supplying to a load an output voltage converted from an input voltage, a detection voltage generation circuit for generating a detection voltage which varies depending on a magnitude of a voltage drop which across the load, and a control circuit for controlling the power supply circuit so that it performs output feedback control of the output voltage, on the basis of the detection voltage.
    Type: Grant
    Filed: January 20, 2016
    Date of Patent: December 20, 2016
    Assignee: ROHM CO., LTD.
    Inventor: Sadakazu Murakami
  • Publication number: 20160135262
    Abstract: A load driving device disclosed in the specification includes a power supply circuit for supplying to a load an output voltage converted from an input voltage, a detection voltage generation circuit for generating a detection voltage which varies depending on a magnitude of a voltage drop which across the load, and a control circuit for controlling the power supply circuit so that it performs output feedback control of the output voltage, on the basis of the detection voltage.
    Type: Application
    Filed: January 20, 2016
    Publication date: May 12, 2016
    Applicant: ROHM CO., LTD.
    Inventor: Sadakazu MURAKAMI
  • Publication number: 20140346958
    Abstract: A load driving device disclosed in the specification includes a power supply circuit for supplying to a load an output voltage converted from an input voltage, a detection voltage generation circuit for generating a detection voltage which varies depending on a magnitude of a voltage drop which across the load, and a control circuit for controlling the power supply circuit so that it performs output feedback control of the output voltage, on the basis of the detection voltage.
    Type: Application
    Filed: August 7, 2014
    Publication date: November 27, 2014
    Inventor: Sadakazu MURAKAMI
  • Patent number: 8836295
    Abstract: A load driving device disclosed in the specification includes a power supply circuit for supplying to a load an output voltage converted from an input voltage, a detection voltage generation circuit for generating a detection voltage which varies depending on a magnitude of a voltage drop which across the load, and a control circuit for controlling the power supply circuit so that it performs output feedback control of the output voltage, on the basis of the detection voltage.
    Type: Grant
    Filed: July 26, 2013
    Date of Patent: September 16, 2014
    Assignee: Rohm Co., Ltd.
    Inventor: Sadakazu Murakami
  • Publication number: 20130314000
    Abstract: A load driving device disclosed in the specification includes a power supply circuit for supplying to a load an output voltage converted from an input voltage, a detection voltage generation circuit for generating a detection voltage which varies depending on a magnitude of a voltage drop which across the load, and a control circuit for controlling the power supply circuit so that it performs output feedback control of the output voltage, on the basis of the detection voltage.
    Type: Application
    Filed: July 26, 2013
    Publication date: November 28, 2013
    Applicant: ROHM CO., LTD.
    Inventor: Sadakazu MURAKAMI
  • Patent number: 8519680
    Abstract: A load driving device disclosed in the specification includes a power supply circuit for supplying to a load an output voltage converted from an input voltage, a detection voltage generation circuit for generating a detection voltage which varies depending on a magnitude of a voltage drop which across the load, and a control circuit for controlling the power supply circuit so that it performs output feedback control of the output voltage, on the basis of the detection voltage.
    Type: Grant
    Filed: March 24, 2010
    Date of Patent: August 27, 2013
    Assignee: Rohm Co., Ltd.
    Inventor: Sadakazu Murakami
  • Patent number: 8242756
    Abstract: A load such as an LED and a constant-current source are connected in series with each other between the node of a dc-dc conversion type power supply circuit providing an output voltage and the ground. The constant-current source provides a constant current Io, the magnitude of which can be adjusted. The power supply circuit controls the output voltage such that the voltage drop across the constant-current source serving as a detection voltage becomes equal to a reference voltage. Thus, the load current can be varied within a predetermined range while avoiding the power loss due to an increase in the load current, thereby always permitting efficient operation of the load.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: August 14, 2012
    Assignee: Rohm Co., Ltd.
    Inventor: Sadakazu Murakami
  • Publication number: 20110181582
    Abstract: A load such as an LED and a constant-current source are connected in series with each other between the node of a dc-dc conversion type power supply circuit providing an output voltage and the ground. The constant-current source provides a constant current Io, the magnitude of which can be adjusted. The power, supply circuit controls the output voltage such that the voltage drop across the constant-current source serving as a detection voltage becomes equal to a reference voltage. Thus, the load current can be varied within a predetermined range while avoiding the power loss due to an increase in the load current, thereby always permitting efficient operation of the load.
    Type: Application
    Filed: April 5, 2011
    Publication date: July 28, 2011
    Applicant: ROHM CO., LTD.
    Inventor: Sadakazu MURAKAMI
  • Patent number: 7944189
    Abstract: A load such as an LED and a constant-current source are connected in series with each other between the node of a dc-dc conversion type power supply circuit providing an output voltage and the ground. The constant-current source provides a constant current Io, the magnitude of which can be adjusted. The power supply circuit controls the output voltage such that the voltage drop across the constant-current source serving as a detection voltage becomes equal to a reference voltage. Thus, the load current can be varied within a predetermined range while avoiding the power loss due to an increase in the load current, thereby always permitting efficient operation of the load.
    Type: Grant
    Filed: April 22, 2009
    Date of Patent: May 17, 2011
    Assignee: Rohm Co., Ltd.
    Inventor: Sadakazu Murakami
  • Patent number: 7880329
    Abstract: A controlling unit generates a pulse signal whose duty ratio is controlled so that the output voltage of each channel will be constant, and controls the main transistor and the rectification circuit of each channel in accordance with the pulse signal. The first synchronous rectification transistor is disposed in a direction such that the cathode of the body diode thereof is on the switching terminal side. The second synchronous rectification transistor is disposed in a direction such that the cathode of the body diode thereof is on the output terminal side. The controlling unit first turns on the first synchronous rectification transistor, and then turns on the second synchronous rectification transistor for a period of time in accordance with the pulse width of the pulse signal.
    Type: Grant
    Filed: December 29, 2008
    Date of Patent: February 1, 2011
    Assignee: Rohm Co., Ltd.
    Inventor: Sadakazu Murakami