Abstract: The lighting apparatus in accordance with the present invention includes: a switching regulator including a switching element; and a control circuit configured to adjust a switching frequency and on-duration of the switching element in accordance with a dimming ratio. The control circuit is configured to, when the dimming ratio falls within a first dimming range, adjust the switching frequency to a frequency associated with the first dimming range and adjust the on-duration to duration corresponding to the dimming ratio. The control circuit is configured to, when the dimming ratio falls within a second dimming range, adjust the on-duration to duration associated with the second dimming range and adjust the switching frequency to a frequency corresponding to the dimming ratio.

Abstract: A lighting device includes lighting control units respectively provided for controlling lighting of solid state light emitting element groups irradiating light of different chromaticities and a color ratio setting unit for setting a target output ratio of the solid state light emitting element groups. In an xy chromaticity diagram of an XYZ color system, a straight line connecting chromaticity coordinates of lights irradiated by a first and a second solid state light emitting element group intersects a black body locus. Further, the lighting control units include a first and a second lighting control unit for controlling lighting of the first and the second solid state light emitting element group, and the first and the second control unit perform a feedback control such that an output ratio of the second to the first solid state light emitting element group becomes equal to the target output ratio thereof.

Abstract: An illumination apparatus is provided for outputting a light of mixed colors in a desired color temperature by controlling light outputs from light sources. The illumination apparatus includes a light output setting unit for outputting a set signal presenting a set value for adjusting an output of the light of mixed colors, and a first filter for smoothing the set signal from the light output setting unit. The illumination apparatus further includes a light output adjustment unit for adjusting the light outputs from the respective light sources based on the set signal smoothed by the first filter, and a plurality of second filters smoothing signals outputted from the light output adjustment unit to the light sources, respectively. Each of time constants of the second filters is lower than that of the first filter.

Abstract: The lighting device according to the present invention includes a power supply circuit, a temperature detection circuit, and a temperature control circuit. The power supply circuit supplies operation power to a light source including a solid state light emitting device. The temperature detection circuit measures a surrounding temperature of the light source and outputs the measured surrounding temperature as a detection temperature. The temperature control circuit determines whether an increase rate of the surrounding temperature exceeds a predetermined criterion value. When determining that the increase rate exceeds the criterion value, the temperature control circuit performs a process of decreasing a temperature of the light source.

Abstract: The lighting device of the present invention includes: a power source configured to supply power to a plurality of light sources; and a cooling control circuit configured to control a plurality of cooling devices for respectively cooling the plurality of light sources. The cooling control circuit includes a power supply circuit, a plurality of output circuits, a plurality of temperature measurement circuits, and an output control circuit. The power supply circuit outputs a constant voltage by use of power from the power source. The output circuits receive the constant voltage from the power supply circuit and supply drive voltages to the plurality of cooling devices respectively. The temperature measurement circuits measure temperatures of the plurality of light sources respectively. The output control circuit regulates the drive voltages respectively supplied from the plurality of output circuits based on the temperatures respectively measured by the plurality of temperature measurement circuits.

Abstract: The lighting device according to the present invention includes: a power source configured to supply power to a light source having a plurality of regions; a plurality of cooling devices arranged corresponding to the plurality of regions to cool the plurality of regions, respectively; and a cooling control circuit configured to control the plurality of cooling devices. The cooling control circuit includes: a plurality of output circuits configured to supply drive voltages to the plurality of cooling devices by use of power from the power source to drive the plurality of cooling devices, respectively; a plurality of temperature measurement circuits configured to respectively measure temperatures of the plurality of regions; and an output control circuit configured to regulate the drive voltages respectively supplied from the plurality of output circuits based on the temperatures respectively measured by the plurality of temperature measurement circuits.

Abstract: A semiconductor light emitting element drive device includes: a converter circuit configured to supply a light source unit with a load current from a first-primary winding; and a current regulation circuit. The converter circuit further includes a second-secondary winding. The current regulation circuit includes a switching device (second switching device) connected in series with the second-secondary winding. In a dimming ratio of the light source unit is lower than a first ratio, the second switching device is controlled to ON and OFF so as to decrease the load current through the light source unit by a shunt of a part of the energy stored in the primary winding.

Abstract: A driver circuit for a semiconductor light-emitting element enables stable dimmed lighting from very low luminance output to rated luminance output by use of a switching power source operating in a discontinuous mode. The driver circuit includes a DC-DC converter, an output sensor, and a feedback controller. The DC-DC converter includes a burst dimming controller for intermittently stopping an ON/OFF operation of a power switch of the DC-DC converter, thereby reducing a current flowing to the semiconductor light-emitting element. The output sensor detects at least one of the current provided to the semiconductor light-emitting element or the voltage of the semiconductor light-emitting element. The feedback controller adjusts an ON time of the power switch during the ON/OFF operation such that a detected value of the output sensor approaches a target value. Near a dimming control lower limit, power is blocked from the feedback controller.

Abstract: 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.

Abstract: A control circuit selects a first control mode in which a switching element is turned on/off so as to flow current in an inductor in a continuous mode by which the current flows in the inductor without a sleep period, thereby fully lighting a light source load. The control circuit selects one of a second control mode in which a turn-on time of the switching element is changed and a third control mode in which an oscillating frequency is changed according to an interval, to which the designated dimming ratio corresponds, to light the light source load. An output capacitor connected between output terminals of a step-down chopper circuit smoothes a pulsation component of an output current supplied to the light source load and has capacity set so that a ripple ratio of the output current is less than 0.5 at the full lighting of the light source load.

Abstract: A switching power circuit includes a first switching element having one end connected to a positive electrode of a first capacitor, a second switching element having one end connected to a negative electrode of the first capacitor, an inductive element having one end connected to the other ends of the first and the second switching element, a semiconductor switching element connected in parallel to the current limiting resistor, and a second capacitor connected to a control electrode of the semiconductor switching element. The second capacitor is charged by using a voltage induced to the inductive element when the first or the second switching element is off.

Abstract: 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.

Abstract: An illumination apparatus, for outputting a light of mixed colors in a desired color temperature by controlling light outputs from light sources, includes: a light output setting unit for outputting a set signal presenting a set value for adjusting an output of the light of mixed colors; a first filter for smoothing the set signal from the light output setting unit; a light output adjustment unit for adjusting the light outputs from the respective light sources based on the set signal smoothed by the first filter; and a plurality of second filters smoothing signals outputted from the light output adjustment unit to the light sources, respectively. Each of time constants of the second filters is lower than that of the first filter.

Abstract: A lighting device includes lighting control units respectively provided for controlling lighting of solid state light emitting element groups irradiating light of different chromaticities and a color ratio setting unit for setting a target output ratio of the solid state light emitting element groups. In an xy chromaticity diagram of an XYZ color system, a straight line connecting chromaticity coordinates of lights irradiated by a first and a second solid state light emitting element group intersects a black body locus. Further, the lighting control units include a first and a second lighting control unit for controlling lighting of the first and the second solid state light emitting element group, and the first and the second control unit perform a feedback control such that an output ratio of the second to the first solid state light emitting element group becomes equal to the target output ratio thereof.

Abstract: A light emitting device includes a set of light source units including multiple types of solid state light emitting elements having different light colors, each of the light source units comprising the same type of the solid state light emitting elements connected in series and; and an information storage unit which stores information about electrical characteristic of the set of light source units. The information stored in the information storage unit represents a relationship between a light output and a drive current in the set of light source units.

Abstract: A driver circuit for a semiconductor light-emitting element enables stable dimmed lighting from very low luminance output to rated luminance output by use of a switching power source operating in a discontinuous mode. The driver circuit includes a DC-DC converter, an output sensor, and a feedback controller. The DC-DC converter includes a burst dimming controller for intermittently stopping an ON/OFF operation of a power switch of the DC-DC converter, thereby reducing a current flowing to the semiconductor light-emitting element. The output sensor detects at least one of the current provided to the semiconductor light-emitting element or the voltage of the semiconductor light-emitting element. The feedback controller adjusts an ON time of the power switch during the ON/OFF operation such that a detected value of the output sensor approaches a target value. Near a dimming control lower limit, power is blocked from the feedback controller.

Abstract: A lighting device for a semiconductor light emitting element includes a series circuit of two switching elements which are alternately turned on, the series circuit being connected to a direct current (DC) input power source and a reactance circuit connected between a connection node of the two switching elements and one end of the DC input power source through a capacitor, an output of the reactance circuit being supplied to the semiconductor light emitting element through a rectifier circuit. A dimming operation of the semiconductor light emitting element is performed by varying a ratio of ON periods of the two switching elements.

Abstract: A lighting device includes a lighting unit which controls a current being supplied to a load, in which light emitting modules, each having one or more semiconductor light emitting elements connected in series, are connected in parallel, to be a constant current; a current detector which detects a current flowing through one of the light emitting modules; and an abnormality detector which compares a detected value from the current detector with an upper limit and a lower limit of a predetermined current range to detect an abnormality in the load. The abnormality detector detects the abnormality in the load if the detected value from the current detector is larger than the upper limit or smaller than the lower limit, and if the abnormality in the load is detected, the lighting unit reduces the current being supplied to the load.

Abstract: A lighting device includes a first and a second gate circuit having a first input to which a high frequency square wave signal generated from a high frequency oscillation circuit is inputted and a second input to which a first low frequency square wave signal is inputted; and a second gate circuit having a first input to which the high frequency square wave signal is inputted and a second input to which a second low frequency square wave signal is inputted. Each of the first and the second low frequency square wave signal has a frequency lower than that of the high frequency square wave signal, and the first and the second low frequency square wave signal determine whether the high frequency square wave signal is supplied, as on/off switching signals, to the first and the second switching power supply circuit, respectively.

Abstract: A switching power circuit includes a first switching element having one end connected to a positive electrode of a first capacitor, a second switching element having one end connected to a negative electrode of the first capacitor, an inductive element having one end connected to the other ends of the first and the second switching element, a semiconductor switching element connected in parallel to the current limiting resistor, and a second capacitor connected to a control electrode of the semiconductor switching element. The second capacitor is charged by using a voltage induced to the inductive element when the first or the second switching element is off.