Abstract: An illumination lighting apparatus is configured to light a plurality of light-emitting elements connected in series to each other. The illumination lighting apparatus includes one photosensor and a detector. The one photosensor is configured to detect light emitted from the plurality of light-emitting elements. The detector is configured to perform detection of a light emission defect on the plurality of light-emitting elements based on the light detected by the one photosensor. Moreover, the detector performs the detection process at an initial stage of lighting of the plurality of light-emitting elements.

Abstract: An illumination lighting apparatus is configured to light a plurality of light-emitting elements connected in series to each other. The illumination lighting apparatus includes one photosensor and a detector. The one photosensor is configured to detect light emitted from the plurality of light-emitting elements. The detector is configured to perform detection of a light emission defect on the plurality of light-emitting elements based on the light detected by the one photosensor. Moreover, the detector performs the detection process when a quantity of light detected by the one photosensor decreases. The detector includes two or more switches and a processor. The two or more switches are connected in parallel to the plurality of light-emitting elements.

Abstract: An illumination lighting apparatus is configured to light a plurality of light-emitting elements connected in series to each other. The illumination lighting apparatus includes one photosensor and a detector. The one photosensor is configured to detect light emitted from the plurality of light-emitting elements. The detector is configured to perform detection of a light emission defect on the plurality of light-emitting elements based on the light detected by the one photosensor. Moreover, the detector performs the detection process at an initial stage of lighting of the plurality of light-emitting elements.

Abstract: An illumination lighting apparatus is configured to light a plurality of light-emitting elements connected in series to each other. The illumination lighting apparatus includes one photosensor and a detector. The one photosensor is configured to detect light emitted from the plurality of light-emitting elements. The detector is configured to perform detection of a light emission defect on the plurality of light-emitting elements based on the light detected by the one photosensor. Moreover, the detector performs the detection process when a quantity of light detected by the one photosensor decreases. The detector includes two or more switches and a processor. The two or more switches are connected in parallel to the plurality of light-emitting elements.

Abstract: A lighting device that supplies current to light-emitting units includes: a DC-to-DC converter; a switch unit connected to the light-emitting units; and a control circuit which controls the DC-to-DC converter and the switch unit. The DC-to-DC converter includes: an inductor through which current from the DC-to-DC converter is provided to the light-emitting units; and a first switch element connected in series with the inductor and which switches ON/OFF. The control circuit includes: a zero-crossing detector that detects that current flowing in the inductor is substantially zero due to the first switch element switching OFF, and outputs a zero-current detection signal; and a switch controller that selects one of the light-emitting units and controls the switch unit to cause the current from the DC-to-DC converter to be supplied to the selected light-emitting unit when the first switch element subsequently switches ON, each time the switch controller receives the zero-current detection signal.

Abstract: A lighting device that supplies current to light-emitting units includes: a DC-to-DC converter; a switch unit connected to the light-emitting units; and a control circuit which controls the DC-to-DC converter and the switch unit. The DC-to-DC converter includes: an inductor through which current from the DC-to-DC converter is provided to the light-emitting units; and a first switch element connected in series with the inductor and which switches ON/OFF. The control circuit includes: a zero-crossing detector that detects that current flowing in the inductor is substantially zero due to the first switch element switching OFF, and outputs a zero-current detection signal; and a switch controller that selects one of the light-emitting units and controls the switch unit to cause the current from the DC-to-DC converter to be supplied to the selected light-emitting unit when the first switch element subsequently switches ON, each time the switch controller receives the zero-current detection signal.

Abstract: An induction lamp lighting device includes an induction coil arranged adjacent to an induction lamp; a direct current power supply circuit for outputting a direct current voltage; a high-frequency power supply circuit for converting the direct current voltage to an alternating current voltage and supplying the alternating current voltage to the induction coil; and a control circuit for controlling the direct current power supply circuit and the high-frequency power supply circuit. The control circuit performs a startup preparation operation by which to control the high-frequency power supply circuit so that, immediately after the alternating current voltage begins to be outputted from the high-frequency power supply circuit to the induction coil, the alternating current voltage is gradually increased to such a voltage value as not to generate arc discharge in the induction lamp and then kept at the voltage value for a specified time.

Abstract: An electric-discharge lamp lightning device includes a first frequency controller for sweeping a switching frequency so that the output of an inverter is gradually increased in order to allow an electric-discharge lamp to be started and lighted, and a second frequency controller for detecting the output power of the inverter by a current flowing in a resonant circuit and controlling the switching frequency so that the output power is set to be a target value after the discharge lamp is started and lighted. The first frequency controller includes a holding means for holding the switching frequency just after the lighting detection when the output power is smaller than the target value at the lighting detection of the electric-discharge lamp by a lighting detection circuit.

Abstract: An electronic ballast for a discharge lamp includes a predictive circuit and a correction circuit in addition to a power conversion circuit including an inverter circuit and a resonant circuit, a drive circuit and a frequency control circuit. The inverter circuit applies load voltage across a load circuit including the lamp via the resonant circuit. The predictive circuit predicts a resonance frequency of the combination of the resonant circuit and the load circuit after ignition of the lamp. The resonance frequency is predicted based on an input signal representing the load voltage in the period of time from the start of sweep of the inverter circuit's operating frequency through a time point immediately after ignition of the lamp. The correction circuit changes the end frequency of the sweep to the resonance frequency.

Abstract: An electric-discharge lamp lightning device includes a first frequency controller for sweeping a switching frequency so that the output of an inverter is gradually increased in order to allow an electric-discharge lamp to be started and lighted, and a second frequency controller for detecting the output power of the inverter by a current flowing in a resonant circuit and controlling the switching frequency so that the output power is set to be a target value after the discharge lamp is started and lighted. The first frequency controller includes a holding means for holding the switching frequency just after the lighting detection when the output power is smaller than the target value at the lighting detection of the electric-discharge lamp by a lighting detection circuit.

Abstract: A dimmable electronic ballast for an electrodeless discharge lamp comprises an inverter circuit, a resonance circuit, an induction coil and a start circuit. The start circuit has a variable time constant. The start circuit sweeps a drive frequency of the inverter circuit through a time constant for start or restart so that the voltage applied across the coil is raised from voltage lower than start voltage and restart voltage for starting and restarting the lamp to voltage higher than the start voltage and the restart voltage. The time constant for start during a start period for starting the lamp is larger than the time constant for restart during a restart period for restarting the lamp.

Abstract: An electronic ballast for a discharge lamp includes a predictive circuit and a correction circuit in addition to a power conversion circuit including an inverter circuit and a resonant circuit, a drive circuit and a frequency control circuit. The inverter circuit applies load voltage across a load circuit including the lamp via the resonant circuit. The predictive circuit predicts a resonance frequency of the combination of the resonant circuit and the load circuit after ignition of the lamp. The resonance frequency is predicted based on an input signal representing the load voltage in the period of time from the start of sweep of the inverter circuit's operating frequency through a time point immediately after ignition of the lamp. The correction circuit changes the end frequency of the sweep to the resonance frequency.

Abstract: An induction lamp lighting device includes an induction coil arranged adjacent to an induction lamp; a direct current power supply circuit for outputting a direct current voltage; a high-frequency power supply circuit for converting the direct current voltage to an alternating current voltage and supplying the alternating current voltage to the induction coil; and a control circuit for controlling the direct current power supply circuit and the high-frequency power supply circuit. The control circuit performs a startup preparation operation by which to control the high-frequency power supply circuit so that, immediately after the alternating current voltage begins to be outputted from the high-frequency power supply circuit to the induction coil, the alternating current voltage is gradually increased to such a voltage value as not to generate arc discharge in the induction lamp and then kept at the voltage value for a specified time.

Abstract: A dimmable electronic ballast for an electrodeless discharge lamp comprises an inverter circuit, a resonance circuit, an induction coil and a start circuit. The start circuit has a variable time constant. The start circuit sweeps a drive frequency of the inverter circuit through a time constant for start or restart so that the voltage applied across the coil is raised from voltage lower than start voltage and restart voltage for starting and restarting the lamp to voltage higher than the start voltage and the restart voltage. The time constant for start during a start period for starting the lamp is larger than the time constant for restart during a restart period for restarting the lamp.

Abstract: Electrodeless discharge lamp lighting device. Start circuit 19 sweeps operating frequency of resonance circuit 16 from start frequency to end frequency of resonance frequency side through drive circuit 18 and DC/AC conversion circuit 15, and starts electrodeless discharge lamp 13. Control circuit 10 increases or decreases variable power into circuit 18 so that detection current comes to equal prescribed current for shifting the operating frequency to middle range frequency between the start frequency and the end frequency. The prescribed current is set so that the detection voltage in case of the middle range frequency becomes lower than that in case of the end frequency. Capacitor 106 constituting integration circuit starts suppression of operation of circuit 10 when lamp 13 is started, and holds the suppression during at least start mode. Accordingly, it is possible to stably start lamp 13 and control stress on circuit(s) after lamp 13 is successfully started.

Abstract: A ballast for an electrodeless discharge lamp includes a high frequency power supply that supplies a high frequency electric power to an induction coil for operating the lamp. A dimmer controller generates a control signal in response to a dimmer command designating a varying dimming ratio. The control signal defines a first period Ton in which the power supply is controlled to apply a coil voltage of a first level V1 to the induction coil for operating the lamp. The first period is followed by a second period Toff in which the power supply is controlled to apply the coil voltage of a second level V2 that is lower than the first level and fails to sustain the lamp. The control signal defines, between the second period and the first period, a starting period Tst in which the coil voltage increases continuously for smooth transition from an off-condition to an on-condition of the lamp.

Abstract: Electrodeless discharge lamp lighting device. Start circuit 19 sweeps operating frequency of resonance circuit 16 from start frequency to end frequency of resonance frequency side through drive circuit 18 and DC/AC conversion circuit 15, and starts electrodeless discharge lamp 13. Control circuit 10 increases or decreases variable power into circuit 18 so that detection current comes to equal prescribed current for shifting the operating frequency to middle range frequency between the start frequency and the end frequency. The prescribed current is set so that the detection voltage in case of the middle range frequency becomes lower than that in case of the end frequency. Capacitor 106 constituting integration circuit starts suppression of operation of circuit 10 when lamp 13 is started, and holds the suppression during at least start mode. Accordingly, it is possible to stably start lamp 13 and control stress on circuit(s) after lamp 13 is successfully started.

Abstract: A ballast for an electrodeless discharge lamp includes a high frequency power supply that supplies a high frequency electric power to an induction coil for operating the lamp. A dimmer controller generates a control signal in response to a dimmer command designating a varying dimming ratio. The control signal defines a first period Ton in which the power supply is controlled to apply a coil voltage of a first level V1 to the induction coil for operating the lamp. The first period is followed by a second period Toff in which the power supply is controlled to apply the coil voltage of a second level V2 that is lower than the first level and fails to sustain the lamp. The control signal defines, between the second period and the first period, a starting period Tst in which the coil voltage increases continuously for smooth transition from an off-condition to an on-condition of the lamp.

Abstract: A power source device includes a high frequency power source having a pair of switching elements and converting a DC voltage into an AC high frequency voltage to be supplied to a load, a driving transformer having, wound on a magnetic core, a primary winding and a pair of secondary windings connected respectively in series to each of control terminals of the pair of the switching elements, and a driving device for driving the two switching elements by applying a voltage to the primary winding of the driving transformer. The secondary windings are wound on the core to be separated in every turn at equal intervals and not to be intimately close to each other, for remarkable improvement in the degree of variability in the efficiency of circuit forming the power source device.