Provided is a light source drive device including: a current supply device; and a light source device including a light emitting element that emits light by receiving drive current supplied from the current supply device, a temperature sensor that performs temperature detection at a position closer to the light emitting element than the current supply device, and a signal generation unit that outputs a control signal for controlling the drive current depending on a detected value of the temperature sensor to the current supply device. The signal generation unit generates a control signal for reducing the drive current depending on a temperature when the temperature detected by the temperature sensor is equal to or higher than a predetermined temperature.

A discharge lamp drive device includes a discharge lamp driver adapted to supply a drive current to a discharge lamp, a control section adapted to control the discharge lamp driver, and a storage section adapted to store a plurality of drive patterns of the drive current. Each of the drive patterns has a plurality of drive parameters. The plurality of drive patterns includes a first drive pattern and a second drive pattern different from each other in a value of at least one of the plurality of drive parameters. The control section is configured to execute the first drive pattern and the second drive pattern in accordance with at least one of accumulated lighting time of the discharge lamp and an individual of the discharge lamp in a case in which an inter-electrode voltage of the discharge lamp is at a predetermined voltage value.

A light source device includes: a lighting circuit that includes a direct-current power source, a transformer, and a switching element, and generates electromotive force in a secondary winding of the transformer in accordance with switching of an ON state and an OFF state of the switching element; a dielectric barrier discharge lamp that is connected to the secondary winding of the transformer, and a controller that performs ON/OFF control on the switching element. The controller performs: a starting mode for repeating ON/OFF control on the switching element at a predetermined frequency at a time of starting; and a steady-state operation mode for alternately performing first control and second control after the dielectric barrier discharge lamp has been started, the first control being performed to repeat ON/OFF control on the switching element at the predetermined frequency, the second control being performed to maintain the switching element in the OFF state.

Drivers (1-7) comprise respective switching circuits (1, 2) for guiding respective current signals during respective time-intervals for the sequential driving of light emitting circuits (91, 92). The respective time-intervals are defined by the fact that amplitudes of a mains signal are in respective ranges during the respective time-intervals. More specifically, there is a bypass switching circuit (5) for guiding a bypass current signal which bypasses all light emitting circuit (91, 92) during an initial time-interval. An adaptation circuit (6, 7) adapts amplitudes of the respective current signals during the respective time-intervals, to reduce a total harmonic distortion. Said adapting may comprise an adaptation in response to information derived from the amplitude of the mains signal, and may comprise shaping the amplitudes of the current signals in response to information derived from the amplitude of the mains signal. Preferably, the shaped amplitudes of the respective current signals will be substantially identical to shapes of the amplitude of the mains signal in the respective ranges. The adaptation circuit (6, 7) may comprise a current source (6) and a definition circuit (7).

A dimmable ballast circuit for a compact fluorescent lamp controls the intensity of a lamp tube in response to a phase-control voltage received from a dimmer switch. The ballast circuit comprises a phase-control-to-DC converter circuit that receives the phase-control voltage, which is characterized by a duty cycle defining a target intensity of the lamp tube, and generates a DC voltage representative of the duty cycle of the phase-control voltage. Changes in the duty cycle of the phase-control voltage that are below a threshold amount are filtered out by the converter circuit, while intentional changes in the duty cycle of the phase-control voltage are reflected in changes in the target intensity level and thereby the intensity level of the lamp tube.

During a normal operation, alternating drive voltage to be applied between a pair of electrodes provided to face an outer surface of a bottom part of a gas discharge light emitting tube is switched to a voltage value V2 lower than a voltage value V1 at the time of starting lighting. Further, the alternating drive voltage to be applied during the normal discharge operation is intermittently applied in a predetermined cycle and duty ratio to enable adjustment of light emission intensity.

Drivers (1-7) comprise respective switching circuits (1, 2) for guiding respective current signals during respective time-intervals for the sequential driving of light emitting circuits (91, 92). The respective time-intervals are defined by the fact that amplitudes of a mains signal are in respective ranges during the respective time-intervals. More specifically, there is a bypass switching circuit (5) for guiding a bypass current signal which bypasses all light emitting circuit (91, 92) during an initial time-interval. An adaptation circuit (6, 7) adapts amplitudes of the respective current signals during the respective time-intervals, to reduce a total harmonic distortion. Said adapting may comprise an adaptation in response to information derived from the amplitude of the mains signal, and may comprise shaping the amplitudes of the current signals in response to information derived from the amplitude of the mains signal. Preferably, the shaped amplitudes of the respective current signals will be substantially identical to shapes of the amplitude of the mains signal in the respective ranges. The adaptation circuit (6, 7) may comprise a current source (6) and a definition circuit (7).

A dimmable ballast circuit for a compact fluorescent lamp controls the intensity of a lamp tube in response to a phase-control voltage received from a dimmer switch. The ballast circuit comprises a phase-control-to-DC converter circuit that receives the phase-control voltage, which is characterized by a duty cycle defining a target intensity of the lamp tube, and generates a DC voltage representative of the duty cycle of the phase-control voltage. Changes in the duty cycle of the phase-control voltage that are below a threshold amount are filtered out by the converter circuit, while intentional changes in the duty cycle of the phase-control voltage are reflected in changes in the target intensity level and thereby the intensity level of the lamp tube.

Provided is a light source drive device including: a current supply device; and a light source device including a light emitting element that emits light by receiving drive current supplied from the current supply device, a temperature sensor that performs temperature detection at a position closer to the light emitting element than the current supply device, and a signal generation unit that outputs a control signal for controlling the drive current depending on a detected value of the temperature sensor to the current supply device. The signal generation unit generates a control signal for reducing the drive current depending on a temperature when the temperature detected by the temperature sensor is equal to or higher than a predetermined temperature.

During a normal operation,alternating drive voltage to be applied between a pair of electrodes provided to face an outer surface of a bottom part of a gas discharge light emitting tube is switched to a voltage value V2 lower than a voltage value V1 at the time of starting lighting. Further, the alternating drive voltage to be applied during the normal discharge operation is intermittently applied in a predetermined cycle and duty ratio to enable adjustment of light emission intensity.