Patents by Inventor Hiromitsu Mizukawa
Hiromitsu Mizukawa 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: 9510411Abstract: An illumination device includes a light emitting unit; and a lighting circuit, to which the light emitting unit is installed, for supplying an output voltage to the light emitting unit. The light emitting unit includes a light emitting element which is connected to an output terminal of the lighting circuit and emits light by the output voltage supplied from the lighting circuit; and a current limiting unit which limits a current flowing into the light emitting element portion from the lighting circuit at the time when the light emitting unit is installed to the lighting circuit.Type: GrantFiled: February 16, 2012Date of Patent: November 29, 2016Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.Inventors: Miyo Hayashi, Hiromitsu Mizukawa
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Patent number: 9089020Abstract: A dimming signal generation device outputs a square wave voltage signal having an on-duty corresponding to a dimming level to a dimming signal line from a time point when a predetermined time period has elapsed after power-up. In the dimming signal generation device, a specific voltage is outputted to the dimming signal line for the predetermined time period after the power-up.Type: GrantFiled: April 30, 2012Date of Patent: July 21, 2015Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.Inventors: Koji Watanabe, Hiromitsu Mizukawa
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Patent number: 8957591Abstract: An illumination system includes a lighting apparatus having a solid-state light emitting element as a light source; and a dimmer including a bidirectional switching element having a self-sustaining function and connected to a serial circuit of the lighting apparatus and an external power source. The dimmer varies a conduction angle of the bidirectional switching element by controlling a phase of an AC voltage of the external power source, wherein the lighting apparatus performs dimming of the light source based on the conduction angle of the bidirectional switching element, and the dimmer continues to apply driving current to the bidirectional switching element during a first period, which is a part of a second period, the bidirectional switching element being allowed to conduct throughout the second period.Type: GrantFiled: February 27, 2012Date of Patent: February 17, 2015Assignee: Panasonic CorporationInventors: Yoshinobu Murakami, Koji Nakagawara, Masahito Ohnishi, Masahiro Naruo, Shigeru Ido, Kazuhiro Nisimoto, Hiromitsu Mizukawa
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Patent number: 8872444Abstract: A lighting device for a solid-state light source includes a DC power source circuit section which flows a current in a solid-state light source by using a charging/discharging current or either one of charging and discharging currents of a inductor connected in series to a switching element, and a current control section having a first switching control unit for changing an ON width of the switching element depending on a dimming level and a second switching control unit for controlling an ON timing of the switching element. The second switching control unit changes a time until the switching element is turned on from a zero-crossing of the discharging current of the inductor such that the time becomes substantially the same when the dimming level is equal to or greater than a predetermined level, and the time becomes longer when the dimming level is less than the predetermined level.Type: GrantFiled: April 13, 2012Date of Patent: October 28, 2014Assignee: Panasonic CorporationInventors: Koji Watanabe, Kazuhiro Nisimoto, Hiromitsu Mizukawa
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Patent number: 8723436Abstract: An LED lighting device includes two or more switching circuits connected between a power source and an LED (light emitting diode) unit, an inrush current limiting circuit which limits an inrush current flowing through the LED lighting device when power is turned on and a trigger circuit which generates a trigger signal of an operation/non-operation of the inrush current limiting circuit from the switching circuits. Further, the inrush current limiting circuit is set in a non-operation state when any one of the switching circuits is started first.Type: GrantFiled: February 16, 2012Date of Patent: May 13, 2014Assignee: Panasonic CorporationInventors: Koji Watanabe, Hiromitsu Mizukawa, Kenji Matsuda
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Patent number: 8716949Abstract: A lighting device for lighting a solid-state light source includes: a DC power circuit unit for converting a power of an input DC power source using a switching element and flowing a current through a solid-state light source; and a control unit for performing a first switching control in which the switching element is turned on/off at a first high frequency and a second switching control in which an ON/OFF operation of the switching element is intermittently stopped at a second frequency lower than the first frequency of the first switching control. When the current flowing through the solid-state light source is changed, the second frequency is varied.Type: GrantFiled: April 26, 2012Date of Patent: May 6, 2014Assignee: Panasonic CorporationInventors: Koji Watanabe, Hiromitsu Mizukawa
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Patent number: 8669721Abstract: A lighting device is capable of realizing a stable dimming control in a wide range of light output. The lighting device includes a DC power circuit for providing power to a switching element of the lighting device. A current controller switches the switching element to enable a current to flow from the DC power circuit through a solid state light source and maintain the current from the DC power circuit through the solid state light source current controller at a predetermined current. The current controller includes a first switching controller operable to change a width of an on-pulse provided to the switching element and a second switching controller operable to determine a burst-on time during which the on-pulses determined by the first switching controller are provided to the switching element. The burst-on time is longer than an on-pulse period of the first switching controller.Type: GrantFiled: March 23, 2012Date of Patent: March 11, 2014Assignee: Panasonic CorporationInventors: Koji Watanabe, Hiromitsu Mizukawa, Nobuo Ukita, Kazuhiro Nishimoto
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Patent number: 8664883Abstract: A lighting device is provided for lighting control of an LED module based on an externally provided dimming control signal. A chopper circuit includes a switch coupled across a DC input and an inductor which receives and stores energy when the switch is turned on, and discharges energy to the LED module when the switch is turned off. A control circuit determines a current value to the switch, and compares the current value to a predetermined value. During normal operation, the switch is turned off when the detected current value reaches the predetermined value and turned back on when inductor discharge has completed. During a dimming operation, the normal operation is intermittently disabled in accordance with the dimming control signal. The dimming control signal may be a low-frequency PWM signal, with the lighting output being dimmed as a result of a duty ratio of the PWM signal.Type: GrantFiled: July 20, 2011Date of Patent: March 4, 2014Assignee: Panasonic CorporationInventors: Akinori Hiramatu, Hiromitsu Mizukawa
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Patent number: 8502463Abstract: An LED driver circuit prevents an increase in output voltage of a DC/DC converter in an open circuit condition associated with removal or failure of an LED lighting device. A DC power source provides a first DC voltage across positive and negative voltage rails. A DC/DC converter includes a switching element which when turned ON/OFF provides a second DC voltage across first and second ends of a capacitor which further define first and second LED lighting device connection terminals. A control circuit, upon receiving a drive power signal, turns ON/OFF the switching element to provide constant current control. A power supply circuit is coupled between the second LED lighting device connection terminal and the negative voltage rail and generates the drive power signal to the control circuit during a detected lighting condition. The power supply circuit further disables the drive power signal during a detected open circuit condition.Type: GrantFiled: February 22, 2011Date of Patent: August 6, 2013Assignee: Panasonic CorporationInventors: Hiromitsu Mizukawa, Kazuhiro Kumada, Yoshifumi Kuroki
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Patent number: 8482222Abstract: A lighting device reliably detects a status (i.e., existence or absence) of a load connection, and enables or disables power output based on the detected load connection status. The device includes a DC-DC converter having input and output terminals, and a DC current conducting element coupled across the output terminals. A load terminal is also coupled across the output terminals and configured to receive an LED unit. A load detection circuit coupled between an input terminal and the load terminal detects the connection status of an LED unit via a DC current passing through the load terminal, and controls a switching operation of the DC-DC converter based on the detected connection status. A diode coupled between the load terminal and the DC current conducting element blocks a DC current path from the input terminals to the load detection circuit through the DC current conducting element.Type: GrantFiled: April 8, 2011Date of Patent: July 9, 2013Assignee: Panasonic CorporationInventors: Akinori Hiramatu, Hiromitsu Mizukawa, Yoshifumi Kuroki
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Patent number: 8390213Abstract: An LED power-source circuit includes an input filter circuit including noise prevention capacitors and a line filter, a diode bridge connected to the input filter circuit, a smoothing capacitor connected to an output of the diode bridge and having a capacitance of 1 ?F or less, a DC-DC conversion circuit connected to the smoothing capacitor, and an LED assembly connected to an output of the DC-DC conversion circuit. Grounding capacitors are coupled to ground from an input power line between the line filter and the diode bridge. The total capacitance from the input power line to ground is set to be 1/200 or less of that of the smoothing capacitor.Type: GrantFiled: January 29, 2010Date of Patent: March 5, 2013Assignee: Panasonic CorporationInventors: Kazuhiro Kumada, Yoshifumi Kuroki, Hiromitsu Mizukawa
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Publication number: 20120299512Abstract: A dimming signal generation device outputs a square wave voltage signal having an on-duty corresponding to a dimming level to a dimming signal line from a time point when a predetermined time period has elapsed after power-up. In the dimming signal generation device, a specific voltage is outputted to the dimming signal line for the predetermined time period after the power-up.Type: ApplicationFiled: April 30, 2012Publication date: November 29, 2012Applicant: Panasonic CorporationInventors: Koji WATANABE, Hiromitsu Mizukawa
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Publication number: 20120286686Abstract: A lighting device for lighting a solid-state light source includes: a DC power circuit unit for converting a power of an input DC power source using a switching element and flowing a current through a solid-state light source; and a control unit for performing a first switching control in which the switching element is turned on/off at a first high frequency and a second switching control in which an ON/OFF operation of the switching element is intermittently stopped at a second frequency lower than the first frequency of the first switching control. When the current flowing through the solid-state light source is changed, the second frequency is varied.Type: ApplicationFiled: April 26, 2012Publication date: November 15, 2012Applicant: Panasonic CorporationInventors: Koji WATANABE, Hiromitsu Mizukawa
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Publication number: 20120262087Abstract: A lighting device for a solid-state light source includes a DC power source circuit section which flows a current in a solid-state light source by using a charging/discharging current or either one of charging and discharging currents of a inductor connected in series to a switching element, and a current control section having a first switching control unit for changing an ON width of the switching element depending on a dimming level and a second switching control unit for controlling an ON timing of the switching element. The second switching control unit changes a time until the switching element is turned on from a zero-crossing of the discharging current of the inductor such that the time becomes substantially the same when the dimming level is equal to or greater than a predetermined level, and the time becomes longer when the dimming level is less than the predetermined level.Type: ApplicationFiled: April 13, 2012Publication date: October 18, 2012Applicant: Panasonic CorporationInventors: Koji WATANABE, Kazuhiro Nisimoto, Hiromitsu Mizukawa
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Publication number: 20120262080Abstract: A lighting device is capable of realizing a stable dimming control in a wide range of light output. The lighting device includes a DC power circuit for providing power to a switching element of the lighting device. A current controller switches the switching element to enable a current to flow from the DC power circuit through a solid state light source and maintain the current from the DC power circuit through the solid state light source current controller at a predetermined current. The current controller includes a first switching controller operable to change a width of an on-pulse provided to the switching element and a second switching controller operable to determine a burst-on time during which the on-pulses determined by the first switching controller are provided to the switching element. The burst-on time is longer than an on-pulse period of the first switching controller.Type: ApplicationFiled: March 23, 2012Publication date: October 18, 2012Inventors: Koji Watanabe, Hiromitsu Mizukawa, Nobuo Ukita, Kazuhiro Nishimoto
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Publication number: 20120223651Abstract: An illumination system includes a lighting apparatus having a solid-state light emitting element as a light source; and a dimmer including a bidirectional switching element having a self-sustaining function and connected to a serial circuit of the lighting apparatus and an external power source. The dimmer varies a conduction angle of the bidirectional switching element by controlling a phase of an AC voltage of the external power source, wherein the lighting apparatus performs dimming of the light source based on the conduction angle of the bidirectional switching element, and the dimmer continues to apply driving current to the bidirectional switching element during a first period, which is a part of a second period, the bidirectional switching element being allowed to conduct throughout the second period.Type: ApplicationFiled: February 27, 2012Publication date: September 6, 2012Applicant: Panasonic CorporationInventors: Yoshinobu MURAKAMI, Koji Nakagawara, Masahito Ohnishi, Masahiro Naruo, Shigeru Ido, Kazuhiro Nisimoto, Hiromitsu Mizukawa
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Publication number: 20120212144Abstract: An illumination device includes a light emitting unit; and a lighting circuit, to which the light emitting unit is installed, for supplying an output voltage to the light emitting unit. The light emitting unit includes a light emitting element which is connected to an output terminal of the lighting circuit and emits light by the output voltage supplied from the lighting circuit; and a current limiting unit which limits a current flowing into the light emitting element portion from the lighting circuit at the time when the light emitting unit is installed to the lighting circuit.Type: ApplicationFiled: February 16, 2012Publication date: August 23, 2012Applicant: Panasonic CorporationInventors: Miyo HAYASHI, Hiromitsu MIZUKAWA
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Publication number: 20120212148Abstract: An LED lighting device includes two or more switching circuits connected between a power source and an LED (light emitting diode) unit, an inrush current limiting circuit which limits an inrush current flowing through the LED lighting device when power is turned on and a trigger circuit which generates a trigger signal of an operation/non-operation of the inrush current limiting circuit from the switching circuits. Further, the inrush current limiting circuit is set in a non-operation state when any one of the switching circuits is started first.Type: ApplicationFiled: February 16, 2012Publication date: August 23, 2012Applicant: Panasonic CorporationInventors: Koji WATANABE, Hiromitsu Mizukawa, Kenji Matsuda
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Publication number: 20120019714Abstract: A lighting device is provided for lighting control of an LED module based on an externally provided dimming control signal. A chopper circuit includes a switch coupled across a DC input and an inductor which receives and stores energy when the switch is turned on, and discharges energy to the LED module when the switch is turned off. A control circuit determines a current value to the switch, and compares the current value to a predetermined value. During normal operation, the switch is turned off when the detected current value reaches the predetermined value and turned back on when inductor discharge has completed. During a dimming operation, the normal operation is intermittently disabled in accordance with the dimming control signal. The dimming control signal may be a low-frequency PWM signal, with the lighting output being dimmed as a result of a duty ratio of the PWM signal.Type: ApplicationFiled: July 20, 2011Publication date: January 26, 2012Inventors: AKINORI HIRAMATU, HIROMITSU MIZUKAWA
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Publication number: 20110248647Abstract: A lighting device reliably detects a status (i.e., existence or absence) of a load connection, and enables or disables power output based on the detected load connection status. The device includes a DC-DC converter having input and output terminals, and a DC current conducting element coupled across the output terminals. A load terminal is also coupled across the output terminals and configured to receive an LED unit. A load detection circuit coupled between an input terminal and the load terminal detects the connection status of an LED unit via a DC current passing through the load terminal, and controls a switching operation of the DC-DC converter based on the detected connection status. A diode coupled between the load terminal and the DC current conducting element blocks a DC current path from the input terminals to the load detection circuit through the DC current conducting element.Type: ApplicationFiled: April 8, 2011Publication date: October 13, 2011Inventors: Akinori Hiramatu, Hiromitsu Mizukawa, Yoshifumi Kuroki