Abstract: A lighting device is provided that includes a lighting controller that controls a light emitter that emits illumination light. The lighting controller includes a first filter that converts a first signal waveform that is defined by a first piecewise linear curve and whose intensity repeatedly increases and decreases into a signal waveform having a smooth rounded curve, and outputs the converted signal waveform as a first output waveform. The lighting controller causes the light emitter to repeatedly increase and decrease the intensity of the illumination light in accordance with the first output waveform.

Abstract: A lighting device which causes a first light source to emit illumination light and a second light source to emit illumination light having a color temperature higher than a color temperature of the illumination light emitted by the first light source includes: an illuminator which includes a first switching element connected in series to the first light source, and a second switching element connected in series to the second light source; an illumination controller which controls the illuminator to place at least one of the first switching element and the second switching element into an off state; and a constant-current controller which detects a sum of values of currents flowing through the first light source and the second light source, and controls the first switching element and the second switching element based on the sum.

Abstract: A first control circuit is configured to detect a value of a load current flowing through a solid-state light source in a lighting time period, and control a control element at a first response speed so as to make the value of the load current agree with a first target value. A second control circuit is configured to detect the value of the load current in the lighting time period, and control the control element at a second response speed so that the value of the load current does not exceed an upper limit that is larger than a first target value. The second response speed is higher than the first response speed.

Abstract: A first control circuit is configured to detect a value of a load current flowing through a solid-state light source in a lighting time period, and control a control element at a first response speed so as to make the value of the load current agree with a first target value. A second control circuit is configured to detect the value of the load current in the lighting time period, and control the control element at a second response speed so that the value of the load current does not exceed an upper limit that is larger than a first target value. The second response speed is higher than the first response speed.

Abstract: A lighting device includes a rectifier circuit, a drive circuit and a current control circuit. Rectifier circuit rectifies an AC voltage into a pulsating voltage to be output. A load circuit including two or more solid light sources connected in series is connected between output terminals of rectifier circuit. The drive circuit changes a number of solid light sources emitting light, according to a change in a voltage value of the pulsating voltage, so that a period of the pulsating voltage includes: a first time period during which a part of the two or more solid light sources emits light; and a second time period during which all of the two or more solid light sources emit light. The current control circuit controls, in at least the second time period, a value of current flowing through load circuit according to an average voltage of the pulsating voltage.

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 light-emitting device includes a light emission controller which causes first and second light-emitting element groups to emit light, by supplying undulating voltage to the first and second light-emitting element groups. The light emission controller supplies the undulating voltage to the first light-emitting element group, during a first period in which a magnitude of the undulating voltage is greater than a first predetermined value and at most a second predetermined value. The second predetermined value is less than a maximum value of the undulating voltage. The light emission controller supplies the undulating voltage to the first and second light-emitting element groups during a second period in which the magnitude of the undulating voltage is greater than the second predetermined value. The first light-emitting element group surrounds the second light-emitting element group.

Abstract: A light-emitting device includes a light emission controller which causes first and second light-emitting element groups to emit light, by supplying undulating voltage to the first and second light-emitting element groups. The light emission controller supplies the undulating voltage to the first light-emitting element group during a first period in which a magnitude of the undulating voltage is greater than a first predetermined value and at most a second predetermined value. The second predetermined value is less than a maximum value of the undulating voltage. The light emission controller supplies the undulating voltage to the first and second light-emitting element groups during a second period in which the magnitude of the undulating voltage is greater than the second predetermined value. The second light-emitting element group surrounds the first light-emitting element group.

Abstract: A lighting device includes a rectifier circuit, a driver circuit and a shunt circuit. The driver circuit is configured to apply respective voltage components contained in a pulsating voltage from the rectifier circuit every period of the pulsating voltage across part and all of solid light sources in response to the pulsating voltage and respective ON voltages of light source circuits including the part and all of the solid light sources. The shunt circuit is electrically connected in parallel with a light source circuit having a lowest ON voltage of the light source circuits, and configured to set a value of an output current from the rectifier circuit to a value proportional to a value of the pulsating voltage while the pulsating voltage is less than the lowest ON voltage.

Abstract: A lighting device includes: a DC power source circuit; an output control circuit including a chopping switch to adjust an output current by chopping of the chopping switch; light source switches respectively connected to the light sources; and a control unit for controlling a time period for which a current flows in the light sources. The control unit controls the output control circuit such that an operation period for which the chopping is conducted and a stop period for which the chopping is stopped are repeated alternately and performs switchover of the light source switches to be sequentially and selectively turned on, and the switchover is conducted during the stop period with a time interval from a beginning of the stop period.

Abstract: A light output control device includes a switching device, multiple signal input ports, a signal selection circuit, and a control circuit. The switching device is to be electrically connected between a direct-current power supply and a light source circuit. The light source circuit includes a semiconductor light emitting element. The multiple signal input ports respectively correspond to multiple kinds of light output control signals. The signal selection circuit selects, when receiving two or more light output control signals indicating different light output levels through the multiple signal input ports, a light output control signal indicating a lowest (or highest) light output level, from the two or more light output control signals. The control circuit performs switching control of the switching device with a duty cycle corresponding to the lowest (or highest) light output level indicated by the light output control signal selected by the signal selecting circuit.

Abstract: A control circuit is configured to convert a DC voltage that is outputted from a DC power supply to a square wave voltage by switching the switching element according to a PWM signal having a duty ratio that corresponds to a light modulation level of the light source unit, and cause the square wave voltage to be outputted to the light source unit. The control circuit includes a voltage controller configured to control an operating voltage for operating the switching element such that at least one of a rising time and a falling time of a current that flows through the switching element is 1 microsecond or more.

Abstract: A lighting device includes a rectifier circuit, a driver circuit and a shunt circuit. The driver circuit is configured to apply respective voltage components contained in a pulsating voltage from the rectifier circuit every period of the pulsating voltage across part and all of solid light sources in response to the pulsating voltage and respective ON voltages of light source circuits including the part and all of the solid light sources. The shunt circuit is electrically connected in parallel with a light source circuit having a lowest ON voltage of the light source circuits, and configured to set a value of an output current from the rectifier circuit to a value proportional to a value of the pulsating voltage while the pulsating voltage is less than the lowest ON voltage.

Abstract: A lighting device includes a rectifier circuit, a drive circuit and a current control circuit. Rectifier circuit rectifies an AC voltage into a pulsating voltage to be output. A load circuit including two or more solid light sources connected in series is connected between output terminals of rectifier circuit. The drive circuit changes a number of solid light sources emitting light, according to a change in a voltage value of the pulsating voltage, so that a period of the pulsating voltage includes: a first time period during which a part of the two or more solid light sources emits light; and a second time period during which all of the two or more solid light sources emit light. The current control circuit controls, in at least the second time period, a value of current flowing through load circuit according to an average voltage of the pulsating voltage.

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 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: A control unit of a light source device after activation time is configured to turn on switches respectively connected in series with light sources, in prescribed order. The light source device and a lighting device are configured to transmit characteristics of the light sources, based on a voltage change depending on a pattern of on and off of the switches.

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 light output control device includes a switching device, multiple signal input ports, a signal selection circuit, and a control circuit. The switching device is to be electrically connected between a direct-current power supply and a light source circuit. The light source circuit includes a semiconductor light emitting element. The multiple signal input ports respectively correspond to multiple kinds of light output control signals. The signal selection circuit selects, when receiving two or more light output control signals indicating different light output levels through the multiple signal input ports, a light output control signal indicating a lowest (or highest) light output level, from the two or more light output control signals. The control circuit performs switching control of the switching device with a duty cycle corresponding to the lowest (or highest) light output level indicated by the light output control signal selected by the signal selecting circuit.

Abstract: A control circuit is configured to convert a DC voltage that is outputted from a DC power supply to a square wave voltage by switching the switching element according to a PWM signal having a duty ratio that corresponds to a light modulation level of the light source unit, and cause the square wave voltage to be outputted to the light source unit. The control circuit includes a voltage controller configured to control an operating voltage for operating the switching element such that at least one of a rising time and a falling time of a current that flows through the switching element is 1 microsecond or more.