Patent application number | Description | Published |
20130099694 | LIGHTING DEVICE AND LIGHTING FIXTURE USING THE SAME - The lighting device in accordance with the present invention includes: a switching regulator including a switching element and an inductor and configured to supply a direct current to a DC light source; a control circuit unit for controlling the switching element in accordance with a dimming signal for determining an on period in which the DC light source is kept turned on and an off period in which the DC light source is kept turned off to adjust luminance of the DC light source; a current detection unit configured to output a detection value indicative of a current flowing through the inductor; and a superimposing circuit unit. The circuit control unit, in the on period, turns off the switching element when an input value received via the input terminal for receiving the detection value exceeds a first threshold, and turns on the switching element when the input value falls below a second threshold, and keeps turning off the switching element in the off period. The superimposing circuit unit is configured to keep the input value not less than the second threshold in the off period. | 04-25-2013 |
20130113394 | LIGHTING SYSTEM AND LUMINAIRE - A lighting system for controlling a plurality of light sources includes at least a first and a second light source, the second light source having a color temperature and relative luminous efficiency higher than those of the first light source. Further, the system includes: a driving unit configured to turn on and off each of the light sources; and a control unit configured to transmit a control signal to the driving unit in response to an input signal. In addition, the control unit transmits the control signal to the driving unit, to perform at least one of a fade-in control in which the first light source is turned on prior to the second light source when turning on the light sources and a fade-out control in which the second light source is turned off or is dimmed, prior to the first light source when turning off the light sources. | 05-09-2013 |
20130127367 | LIGHTING DEVICE AND ILLUMINATION APPARATUS - A lighting device includes: a DC converter including at least an inductor, a switching unit and a diode and being configured to output an energy accumulated in the inductor to a load via the diode by using an input from a DC power source when the switching unit is turned off; a load voltage detection unit connected to the load to detect a load voltage of the load; and an abnormality determining unit configured to determine an abnormality when the load voltage is equal to or less than a preset threshold voltage. The device further includes an output control unit configured to drive the switching unit so that oscillation of the switching unit is stopped or the output of the DC converter is decreased when the abnormality is determined. | 05-23-2013 |
20140070721 | SOLID-STATE LIGHT-EMITTING ELEMENT DRIVE DEVICE, LIGHTING SYSTEM AND LIGHTING FIXTURE - In a conventional example, even if a duty cycle of the burst dimming is changed during an OFF-period of a switching element, current flowing to an LED is maintained constant. On the other hand, in the present embodiment, an accumulated value of ON-periods of a switching element is increased or decreased so as to be linked to a minimum variation width for a duty cycle (a dimming level) of a dimming signal, regardless of a timing of when the duty cycle is changed. Therefore, a lighting system (an LED drive device) according to the present embodiment can change smoothly a light output of a solid-state light-emitting element (a light source) with respect to a change in a duty cycle of the burst dimming while preventing the switching frequency from increasing. | 03-13-2014 |
20140077719 | SOLID-STATE LIGHT-EMITTING ELEMENT DRIVE DEVICE, LIGHTING SYSTEM AND LIGHTING FIXTURE - A solid-state light-emitting element drive device includes a switching regulator and a control circuit. The switching regulator includes a series circuit of a switching element and an inductor, a regenerative element configured to allow a regenerative current to flow therethrough from the inductor when the switching element is turned off, and output terminals configured so that a solid-state light-emitting element is connected therebetween. The control circuit is configured to control a switching operation of the switching element of the switching regulator. The control circuit is configured to suppress an output power of the switching regulator if a parameter obtained from at least one of an ON-period and an OFF-period of the switching element is out of a prescribed range. | 03-20-2014 |
20150084534 | LIGHTING APPARATUS AND ILLUMINATION SYSTEM USING THE SAME - A lighting apparatus includes a power supply unit and a control unit configured to control the power supply unit. The control unit determines, at a time of activation of the lighting apparatus, a first color temperature of the load at an initial stage of lighting based on a command value. Thereafter, the control unit controls the power supply unit such that the light quantity and the color temperature of the load change according to a second output characteristic during a period in which the color temperature of the load changes from the first color temperature to a second color temperature. The second color temperature is a color temperature, in the first output characteristic, corresponding to the command value. A correspondence relationship between a plurality of light quantities and a plurality of color temperatures defined by the second output characteristic is different from that of the first output characteristic. | 03-26-2015 |
20150091464 | LIGHTING DEVICE, ILLUMINATION DEVICE, ILLUMINATION APPARATUS AND ILLUMINATION SYSTEM - A lighting device includes an AC to DC conversion unit for receiving a setting signal and converting it into a DC voltage having a predetermined voltage, voltage conversion units for converting the DC voltage inputted from the AC to DC conversion unit and driving the light source modules according to drive signals, a PWM signal generating unit for generating a PWM signal having a duty ratio corresponding to the setting signal, and a control unit, by outputting the drive signals to the voltage conversion units based on a command value determined according to the duty ratio, for controlling output powers of the voltage conversion units such that a characteristic curve of the sum of the output powers of the voltage conversion units has the maximum or at least one inflection point within an adjustment range of the conduction angle. | 04-02-2015 |
20150091468 | LIGHTING DEVICE AND LUMINAIRE USING THE SAME - A lighting device for lighting a solid light-emitting element includes: a DC power source circuit configured to output DC power; a power conversion circuit including a semiconductor element connected between output terminals of the DC power source circuit, the power conversion circuit configured to supply power to the solid light-emitting element through a control of a conduction state of the semiconductor element; a first control circuit configured to control an output of the DC power source circuit; a second control circuit configured to control an output of the power conversion circuit by controlling the conduction state of the semiconductor element; and a short-circuit detection circuit configured to detect a short-circuit in the semiconductor element. The first control circuit reduces the output of the DC power source circuit when the short-circuit detection circuit detects the short-circuit in the semiconductor element. | 04-02-2015 |