Abstract: A power supply device includes a control circuit and a first circuit. The control circuit switches between a current control mode and a voltage control mode according to an inputted dimming signal and thus dims a light-emitting element. In the current control mode the control circuit controls an output current supplied to the light-emitting element to a target current, and in the voltage control mode the control circuit controls an output voltage supplied to the light-emitting element to a target voltage. The first circuit detects the output current and the output voltage, and sets the target voltage at which switching between the current control mode and the voltage control mode is carried out as a first voltage.

Abstract: A dedicated power source for LED lamps capable of reliably detecting attachment of an LED lamp is provided. A dedicated power source has a DC power source portion, and includes a lighting circuit which receives power supplied from the DC power source portion and light-controls an LED lamp including an LED element and a detection resistor connected in parallel to the LED element and an attachment detecting portion for detecting attachment of the LED lamp based on a voltage level changing in accordance with attachment/detachment of the detection resistor by attachment/detachment of the LED lamp.

Abstract: A DC power source unit 37 is provided which boosts source voltage from a power source portion 36. A lighting circuit 38 is provided which supplies DC voltage to loads, the DC voltage being obtained by stepping down output current of the DC power source circuit 37. A control circuit 39 is provided which controls the lighting circuit 38 in accordance with at least either voltage or current of LEDs 25 and controls the DC power source unit 37 so that a ratio of output voltage to voltage of the LEDs 25 becomes a preset fixed ratio.

Abstract: According to one embodiment, a luminaire includes a lighting circuit configured to light a light source with a power supply from the outside, an accumulated-lighting-time storing section configured to store accumulated lighting time of the light source, and a control circuit configured to control the lighting circuit in a set mode. The control circuit sets, if a pattern for turning on and off the power supply from the outside is a predetermined initial illuminance correction setting pattern, a mode in an initial illuminance correction mode for performing initial illuminance correction corresponding to the accumulated lighting time of the light source. The control circuit sets, if the pattern for turning on and off the power supply from the outside is a predetermined normal setting pattern, the mode in a normal mode for not performing the initial illuminance correction.

Abstract: According to one embodiment, a direct-current power supply device and an LED lighting apparatus are provided in which arc discharge is more certainly detected and versatility can be improved. The direct-current power supply device includes a constant-current circuit, a voltage detection unit, a current detection unit and a control unit. The constant-current circuit is supplied with power by an external power supply and outputs a constant current to an LED. The voltage detection unit detects one of a load voltage and an electric quantity corresponding to the load voltage. The current detection unit detects one of a load current and an electric quantity corresponding to the load current. The control unit reduces or stops the output current from the constant-current circuit if a detected value of the voltage detection unit increases and a detected value of the current detection unit does not at least increase.

Abstract: A power supply device includes a control circuit and a first circuit. The control circuit switches between a current control mode and a voltage control mode according to an inputted dimming signal and thus dims a light-emitting element. In the current control mode the control circuit controls an output current supplied to the light-emitting element to a target current, and in the voltage control mode the control circuit controls an output voltage supplied to the light-emitting element to a target voltage. The first circuit detects the output current and the output voltage, and sets the target voltage at which switching between the current control mode and the voltage control mode is carried out as a first voltage.

Abstract: According to one embodiment, a lighting device includes a control circuit that includes a threshold for a case where a pair of the illumination lamps are connected in series between a positive output end and a negative output end of a power supply circuit, and a threshold for a case where one illumination lamp is connected between the positive output end and the negative output end of the power supply circuit. The control circuit determines the connected lamp number of the illumination lamps to a direct-current power supply device based on a voltage between the positive output end and the negative output end of the power supply circuit and a voltage between a non-potential connection end and the positive output end or the negative output end, and selects the threshold corresponding to the connected lamp number to control the direct-current power supply device.

Abstract: A light-emitting device and an illumination apparatus are disclosed. A plurality of LED elements are connected in series between positive and negative lines, and first bypass capacitor is connected in parallel to the LED elements respectively. Each series circuit of a predetermined number of LED elements is connected in parallel to second bypass capacitors. As a result, with the negative power line set as a grounding point, the AC impedance at connection points of the series circuit of the LED elements against the ground is reduced. Thus, the erroneous lighting or “flicker” of each LED which otherwise might be caused by an external noise is prevented.

Abstract: In one embodiment, a DC power supply unit includes a DC power supply source; a load circuit connected to an output end of the DC power supply source; a load state detection device to detect a load voltage or an electric quantity corresponding to the load voltage; and a control device to receive the detected output of the load state detection device. The control device controls a maximum output voltage of the DC power supply source so that the voltage difference between the maximum output voltage of the DC power supply source and the load voltage at the time of normal operation falls within a predetermined range in which arc discharge is suppressed.

Abstract: According to one embodiment, a first control section controls a power supply voltage converting circuit and, if an abnormality detecting section detects an abnormality of a load, controls an output of the power supply voltage converting circuit to be stopped or reduced. A second control section gives a command to the first control section and, if the abnormality detecting section detects the abnormality of the load, controls the first control section to stop or reduce the output of the power supply voltage converting circuit.

Abstract: The LED lighting device includes a lighting circuit unit, a current detecting unit, a voltage detecting unit, and a control unit. The lighting circuit unit is adapted in use to be connected to a lamp socket to be connected to a LED lamp, and is configured to provide an output voltage in the form of a DC voltage to the lamp socket in a manner to turn on the LED lamp. The current detecting unit is configured to detect an output current which is caused by the output voltage and is supplied from said lighting circuit unit to said lamp socket. The voltage detecting unit is configured to detect the output voltage of said lighting circuit unit. The control unit configured to control the lighting circuit unit.

Abstract: In a power supply unit, if a dimmer rate is changed within a range of k1, k2, . . . k7 by a dimmer signal k of a dimmer signal generator, light-emitting diodes are controlled to be lighted by a constant current characteristic in an area where the dimmer rate is small according to a load characteristic corresponding to the dimmer rates k1, k2, . . . k7. As the dimmer rate becomes larger, a tendency of a constant voltage characteristic is gradually strengthened from a constant current characteristic so that the light-emitting diodes are lighted at the larger dimmer rate.

Abstract: An LED lighting device includes light emitting diode, a current control circuit having a first series circuit of first and second switching elements, a second series circuit of third and fourth switching elements, and a condenser, which is configured so that the first and second series circuits are parallel connected and the condenser is connected between a connection point of the first and second switching elements and a connection point of the third and fourth switching elements, and a control circuit for alternatively on-off controlling a pair of the first and fourth switching elements and a pair of the second and third switching elements.

Abstract: Certain embodiments provide an LED lighting equipment including a lighting main body. An LED power device has a DC power source and a DC-DC converter having an input terminal connected to the DC power source and the DC-DC converter having an output terminal. An LED light source has a board and a plurality of LED packages; each including a plurality of LED chips connected in series. The LED packages are mounted on the board and connected in series to the output terminal of the DC-DC converter.

Abstract: According to one embodiment, an LED lighting circuit includes a lighting circuit provided between an external power supply and LED elements and a control circuit that controls the lighting circuit. The lighting circuit includes an electrolytic capacitor, the capacitance of which decreases to be lower than a rated value or the impedance of which increases to be higher than a rated value at temperature equal to or lower than ?20° C. The control circuit performs an initial lighting operation under a temperature environment equal to or lower than ?20° C.

Abstract: In a power supply unit, if a dimmer rate is changed within a range of k1, k2, . . . k7 by a dimmer signal k of a dimmer signal generator, light-emitting diodes are controlled to be lighted by a constant current characteristic in an area where the dimmer rate is small according to a load characteristic corresponding to the dimmer rates k1, k2, . . . k7. As the dimmer rate becomes larger, a tendency of a constant voltage characteristic is gradually strengthened from a constant current characteristic so that the light-emitting diodes are lighted at the larger dimmer rate.

Abstract: According to one embodiment, a luminaire includes a lighting circuit configured to light a light source with a power supply from the outside, an accumulated-lighting-time storing section configured to store accumulated lighting time of the light source, and a control circuit configured to control the lighting circuit in a set mode. The control circuit sets, if a pattern for turning on and off the power supply from the outside is a predetermined initial illuminance correction setting pattern, a mode in an initial illuminance correction mode for performing initial illuminance correction corresponding to the accumulated lighting time of the light source. The control circuit sets, if the pattern for turning on and off the power supply from the outside is a predetermined normal setting pattern, the mode in a normal mode for not performing the initial illuminance correction.

Abstract: According to one embodiment, a lighting device includes a control circuit that includes a threshold for a case where a pair of the illumination lamps are connected in series between a positive output end and a negative output end of a power supply circuit, and a threshold for a case where one illumination lamp is connected between the positive output end and the negative output end of the power supply circuit. The control circuit determines the connected lamp number of the illumination lamps to a direct-current power supply device based on a voltage between the positive output end and the negative output end of the power supply circuit and a voltage between a non-potential connection end and the positive output end or the negative output end, and selects the threshold corresponding to the connected lamp number to control the direct-current power supply device.

Abstract: According to one embodiment, a lighting device includes a power supply circuit and a control circuit. The power supply circuit lights a light source. The control circuit determines a threshold based on an output from the power supply circuit to the light source, and controls the power supply circuit to cause a protecting operation to be performed when an output voltage of the power supply circuit deviates from the threshold.

Abstract: According to one embodiment, a lighting device includes a lighting circuit, a lighting time measuring circuit, an initial illuminance correction control circuit and a dimming control circuit. The lighting circuit lights an illumination lamp. The lighting time measuring circuit counts a lighting time of the illumination lamp. The initial illuminance correction control circuit performs initial illuminance correction control of the lighting circuit according to the lighting time counted by the lighting time measuring circuit, and controls light output of the illumination lamp to be constant during life of the illumination lamp. The dimming control circuit performs dimming lighting control of the lighting circuit according to a dimming signal.