Abstract: A lighting device includes a power conversion unit, an impedance adjustment unit, a first control unit, and a second control unit. The power conversion unit is configured to convert input power to direct-current power used for a light source. The impedance adjustment unit is formed of a series circuit of a resistor element and a switch element and is coupled to the light source in parallel, relative to the power conversion unit. The second control unit is configured to cause the power conversion unit to operate, for each burst cycle, for an operation period which is not longer than the burst cycle, and increase and reduce the ratio of the operation period to the burst cycle. The first control unit is configured to make the switch element conductive for a predetermined adjustment period which is not longer than the operation period, during the operation period.

Abstract: A lighting device includes a first current controller, a second current controller, and a charging current controller. The first current controller is configured to control current flowing through a light source so that the current flowing through the light source does not exceed a first predefined value. The charging current controller is configured to control current flowing through a storage element. The second current controller is configured to control current flowing through a first light source so that the current flowing through the first light source does not exceed a second predefined value.

Abstract: In a lighting device, each of n circuit blocks includes a current controller, a storage element, a charging current controller, a charging rectifier element, and a discharging rectifier element. A first circuit block of the n circuit blocks is configured such that a pulsating voltage generated by rectifying a sine wave AC voltage is applied to the series circuit of the current controller and one light source electrically connected to the first circuit block. An i-th circuit block of the n circuit blocks is electrically connected in parallel to the current controller of an i-1-th circuit block via an i-1-th connection rectifier element.

Abstract: 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.

Abstract: The light source unit includes a light source circuit including N (N?3) pairs of a light source group including one or more solid light emitting elements and a constant current circuit connected in series with the light source group to keep, constant, current flowing through the light source group, a full-wave rectification circuit for performing full-wave rectification on AC voltage, and a control circuit. The first pair is connected to the full-wave rectification circuit. The k-th (2?k?N) pair is connected in parallel with the constant current circuit of the (k?1)-th pair so that the light source groups of the k-th and (k?1)-th pairs are in series. The control circuit terminates operations of the constant current circuits of the N pairs or limits currents flowing through the light source groups of the N pairs in response to detection of light or a signal.

Abstract: 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.

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: An electronic ballast includes an AC-DC converter, a DC-DC converter, a cooling device and a power supply. The cooling device is configured to cool the light source. The power supply includes a first power supply configured to generate a first operating voltage from a first voltage obtained from a chopper circuit included in the AC-DC converter to supply the first operating voltage to at least one of the AC-DC converter and the DC-DC converter. The power supply further includes a second power supply configured to generate a second operating voltage from a second voltage obtained from the chopper circuit to supply the second operating voltage to at least the cooling device of the AC-DC converter, the DC-DC converter and the cooling device.

Abstract: An illumination device includes a main light source block having a plurality of main light sources and a plurality of current limiters, and an auxiliary light source block having an auxiliary light source and a constant-current unit. A series circuit of the auxiliary light source and the constant-current unit is electrically connected in parallel with the main light source block, between first and second output terminals of a rectifier. A smoothing capacitor is electrically connected in parallel with a specific main light source among the plurality of main light sources. The specific main light source and a corresponding current limiter are electrically connected in parallel with the series circuit of the auxiliary light source and the constant-current unit.

Abstract: A lighting device includes a rectifier, a constant current regulator and a charge-discharge circuit. The constant current regulator is electrically connected in series with first and second solid-state light-emitting element arrays between a pair of output terminals of the rectifier. The constant current regulator is configured to adjust a current flowing through the second solid-state light-emitting element array to a constant current. The charge-discharge circuit is electrically connected in series with the first solid-state light-emitting element array between the pair of output terminals of the rectifier. The charge-discharge circuit includes a charge storage element, and is configured so that a charge current flows to the charge storage element through the first solid-state light-emitting element array, and so that a discharge current flows from the charge storage element to the second solid-state light-emitting element array.

Abstract: A controller circuit is configured to adjust the number of light-emitting diodes that a current flows from a rectifier circuit through so that: the number of light-emitting diodes, which are lit, of the plurality of light-emitting diodes increases according to a value of a pulsating voltage during a time period that the value of the pulsating voltage increases; and the number of light-emitting diodes, which are lit, of the plurality of light-emitting diodes decreases according to the value of the pulsating voltage during a time period that the value of the pulsating voltage decreases. Light-emitting diodes, which start to emit light by a higher voltage value, of the plurality of light-emitting diodes are disposed at a position nearer to an outside of a mounting region of a substrate than light-emitting diodes, which start to emit light by a lower voltage value, of the plurality of light-emitting diodes.

Abstract: A lighting device includes: a plurality of DC power supply circuits. A plurality of light sources and switching units are connected to each of the DC power supply circuits, the switching units being configured to respectively switch electrical connection between the light sources and said each of the DC power supply circuits. A difference in rated voltage between any two light sources connected to one of the plurality of DC power supply circuits in common is smaller than a difference in rated voltage between two light sources respectively connected to different DC power supply circuits of the plurality of DC power supply circuits.

Abstract: A controller has a first mode and a second mode. First mode is of generating a PWM signal that has a duty ratio to be changed according to a luminous level for a light emitting element and has a constant amplitude. Second mode is of generating a PAM signal that has a constant duty ratio and has an amplitude to be changed according to the luminous level for the light emitting element. Controller is configured to apply one of PWM signal in first mode and PAM signal in second mode to a control terminal of a switching element, when the luminous level is a predetermined level or more. Controller is configured to apply the other of PWM signal in first mode and PAM signal in second mode to the control terminal of the switching element, when the luminous level is less than the predetermined level.

Abstract: A lighting device includes a step-down circuit configured to convert an input voltage into a DC voltage by no insulation, and a control circuit configured to control the step-down circuit. The step-down circuit has an input end, and the step-down circuit is provided on a side of the input end with an overcurrent protector. The overcurrent protector is configured to be fused by flowing of an overcurrent. The step-down circuit has an output end, a side of which is connected in parallel with a switching circuit. The switching circuit includes a switching element. The control circuit is configured to turn on the switching element according to an output voltage of the step-down circuit.

Abstract: In first mode, controller is configured, when receiving a dimming instruction signal, to control voltage-adjusting part to provide a DC voltage with a magnitude corresponding to a luminous level, across output ends of DC power supply, and apply a control voltage with a magnitude kept constant to a control terminal of switching element. In second mode, controller is configured, when receiving the dimming instruction signal, to apply the control voltage with a magnitude corresponding to luminous level to the control terminal of switching element, and control voltage-adjusting part to provide the DC voltage with a magnitude kept constant, across the output ends of DC power supply. Controller is configured to operate in one of first and second modes when luminous level is predetermined level or more, and in the other of first and second modes when luminous level is less than predetermined level.

Abstract: An illumination device includes a main light source block having a plurality of main light sources and a plurality of current limiters, and an auxiliary light source block having an auxiliary light source and a constant-current unit. A series circuit of the auxiliary light source and the constant-current unit is electrically connected in parallel with the main light source block, between first and second output terminals of a rectifier. A smoothing capacitor is electrically connected in parallel with a specific main light source among the plurality of main light sources. The specific main light source and a corresponding current limiter are electrically connected in parallel with the series circuit of the auxiliary light source and the constant-current unit.

Abstract: A lighting device includes a rectifier, a constant current regulator and a charge-discharge circuit. The constant current regulator is electrically connected in series with first and second solid-state light-emitting element arrays between a pair of output terminals of the rectifier. The constant current regulator is configured to adjust a current flowing through the second solid-state light-emitting element array to a constant current. The charge-discharge circuit is electrically connected in series with the first solid-state light-emitting element array between the pair of output terminals of the rectifier. The charge-discharge circuit includes a charge storage element, and is configured so that a charge current flows to the charge storage element through the first solid-state light-emitting element array, and so that a discharge current flows from the charge storage element to the second solid-state light-emitting element array.

Abstract: A controller circuit is configured to adjust the number of light-emitting diodes that a current flows from a rectifier circuit through so that: the number of light-emitting diodes, which are lit, of the plurality of light-emitting diodes increases according to a value of a pulsating voltage during a time period that the value of the pulsating voltage increases; and the number of light-emitting diodes, which are lit, of the plurality of light-emitting diodes decreases according to the value of the pulsating voltage during a time period that the value of the pulsating voltage decreases. Light-emitting diodes, which start to emit light by a higher voltage value, of the plurality of light-emitting diodes are disposed at a position nearer to an outside of a mounting region of a substrate than light-emitting diodes, which start to emit light by a lower voltage value, of the plurality of light-emitting diodes.

Abstract: A lighting device is configured such that only one of a first current control circuit and a charging current control circuit operates in any of operation modes from a first mode to a fourth mode. The lighting device is configured such that the first current control circuit and the charging current control circuit are not included in the same closed circuit.

Abstract: A lighting device includes: first and second power feed terminals between which a light source of a light source device is configured to be electrically connected; a power supply circuit having output ends electrically connected respectively to the first and second power feed terminals and configured to output a DC power across the first and second power feed terminals; a control circuit configured to control the power supply circuit; and at least one identifying terminal for identifying a rated current of a light source. The control circuit is configured to identify a rated current of a light source connected between the first and second power feed terminals by detecting whether the identifying terminal is in floating state or not, and to control the power supply circuit so as to supply a current corresponding to the identified rated current through the first and second power feed terminals.