Abstract: There is provided an LED lighting device having a satisfactory temperature characteristic and a small amount of variation in output current. The step-down chopper is provided with a first circuit including the switching element, the impedance means and a first inductor connected in series and a second circuit including the first inductor and a diode connected in series. A self-excited drive signal generation circuit is provided with a second inductor magnetically coupled with the first inductor and applies a voltage induced in the second inductor to the switching element to keep the switching element on. A turn-off circuit outputs an output voltage when the voltage of the impedance means detected by a comparator exceeds the reference value, and the output voltage allows a switching element to turn on to short-circuit the output terminals of the self-excited drive signal generation circuit, resulting in that the switching element is turned off.

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.

Abstract: According to one embodiment, a lighting device includes a lighting circuit. The lighting circuit includes a direct-current power supply and a DC-DC converter, and lights an illumination lamp by constant-current control. An output capacitor is connected in parallel to an output end of the DC-DC converter. A capacitance of the output capacitor is set to such a value that a peak value of a pulse-like current flowing when the illumination lamp is instantaneously detached from and attached to the output end of the DC-DC converter is one or more and four or less times a load current of the illumination lamp.

Abstract: According to one embodiment, a lighting device includes a lighting circuit and a control circuit. The lighting circuit includes an output end to which an illumination lamp is connected, and lights the illumination lamp by a direct-current power. The control circuit controls the lighting circuit so that power consumption caused by a contact resistance at a connection part between the illumination lamp and the output end of the lighting circuit during whole light lighting of the illumination lamp does not exceed a specified value set to 8 W or less.

Abstract: An illuminating device includes a plurality of kinds of LEDs that emit light having different color temperatures; a plurality of LED lighting circuits that independently light the LEDs for each color temperature of emitted light; and a control unit that selects a first control changing illuminance of the LEDs as a whole by controlling the lighting of the LEDs and a second control changing the colors of light of the LEDs as a whole by controlling the lighting of the LEDs, and corrects an illuminance difference generated before and after the second control.

Abstract: In one embodiment, a lighting device includes an LED lighting circuit and an LED load constituted by a plurality of parallel circuits formed by connecting a plurality of LED elements in parallel, and a series circuit formed by connecting the parallel circuits. The series circuit is connected with an output terminal of the lighting device. In case one LED element becomes open fault mode in one of the parallel circuit, the other LED elements continue lighting. In case two or more LED elements become the open fault mode, the other LED elements also become the open fault mode, and all the LED elements turn off.

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: 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: According to one embodiment, there is provided a lighting fixture including a fixture body, straight-tube type LED lamps each having semiconductor light emitting elements, and a dedicated power source for lighting the semiconductor light emitting elements. The dedicated power source outputs current having a trapezoidal waveform a period of a peak portion of which is 54% or more of one cycle, and thus lights the semiconductor light emitting elements.

Abstract: An LED lamp system which suppresses flickering of an LED element is provided. The LED lamp system includes straight-tube type LED lamps each having LED elements and a dedicated power source for lighting the LED elements. The dedicated power source full-wave rectifies and smoothes a commercial AC power source, outputs constant current having a ripple factor of 1.3 or smaller and thus lights the LED elements.

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, an LED lighting device includes a DC source, a non-insulated step-down chopper and a light emitting diode. The non-insulated step-down chopper includes: a first circuit in which a switching element, a current detecting impedance element and an inductor are connected in series to each other; a second circuit in which the inductor and a freewheel diode are connected in series to each other; and a control portion for controlling the switching element. A power portion including the switching element and the control portion are constituted by a single package IC, and the current detecting impedance element and inductor are attached to the outside of the IC.

Abstract: A lighting circuit according to embodiments includes: a self-hold element connected in series to an AC power source that generates power for lighting an illumination load, together with the illumination load, the self-hold element being configured to control supply of the power provided by the AC power source to the illumination load by the self-hold element being turned on/off; a noise prevention circuit connected in parallel to the self-hold element; and a damping circuit configured to connect a damping resistance to the noise prevention circuit parallely only for a predetermined period from turning-on of the self-hold element, thereby preventing the self-hold element from being repeatedly turned on/off during a period in which the self-hold element is on under normal conditions, due to a transient during power supply.

Abstract: There is provided an LED lighting device having a satisfactory temperature characteristic and a small amount of variation in output current. The step-down chopper is provided with a first circuit including the switching element, the impedance means and a first inductor connected in series and a second circuit including the first inductor and a diode connected in series. A self-excited drive signal generation circuit is provided with a second inductor magnetically coupled with the first inductor and applies a voltage induced in the second inductor to the switching element to keep the switching element on. A turn-off circuit outputs an output voltage when the voltage of the impedance means detected by a comparator exceeds the reference value, and the output voltage allows a switching element to turn on to short-circuit the output terminals of the self-excited drive signal generation circuit, resulting in that the switching element is turned off.

Abstract: The inverter circuit is feedback-controlled by a substantial current flowing into the discharge lamp, which is detected by the current detecting means. A high starting voltage is supplied to the discharge lamp with the operation frequency lowered by the control circuit after the end of a preheating action. The inverter circuit is controlled so that the current of the discharge lamp becomes a desired current value as soon as the current detecting means detects the current substantially flowing into the discharge lamp. The discharge lamp can be prevented from being instantaneously brightly lit without separately providing any structure for detecting lighting of the discharge lamp.

Abstract: The present invention provides a lighting device capable of controlling finely modulated light control without stopping other processing regardless of an operation clock. The light modulation signal generating portion calculates a cycle of a PWM signal based on the lighting state of lamp, which is detected by state detecting portion and a predetermined operation clock. A PWM signal of the cycle calculated by the state detecting portion is generated by the light modulation signal generating portion capable of generating the PWM signal corresponding to the cycle of a non-integral number of times of the operation clock, wherein the cycle of the PWM signal can be continuously and finely varied without stopping other processing regardless of operation clocks, and fine modulated light control is enabled.

Abstract: A fluorescent lamp lighting apparatus according to the present invention comprises an initial illuminance correction control circuit which sets a fluorescent lamp to an initial illuminance correction control lighting mode, a switching portion which changes the fluorescent lamp from the initial illuminance correction control lighting mode to an external control dimming mode when a predetermined external dimming signal is detected, and a control portion which gradually dimming so as to achieve a dimming level of a switched mode when switching the initial illuminance correction control lighting mode and the external control dimming mode, and control so as to achieve a dimming level corresponding to a cumulative lighting time of the fluorescent lamp when the changed mode is the initial illuminance correction control lighting mode.

Abstract: A fluorescent lamp lighting apparatus according to the present invention comprises an initial illuminance correction control circuit which sets a fluorescent lamp to an initial illuminance correction control lighting mode, a switching portion which changes the fluorescent lamp from the initial illuminance correction control lighting mode to an external control dimming mode when a predetermined external dimming signal is detected, and a control portion which gradually dimming so as to achieve a dimming level of a switched mode when switching the initial illuminance correction control lighting mode and the external control dimming mode, and control so as to achieve a dimming level corresponding to a cumulative lighting time of the fluorescent lamp when the changed mode is the initial illuminance correction control lighting mode.