A discharge lamp driving device includes a discharge lamp driving unit configured to supply a driving current to a discharge lamp including electrodes, a controller configured to control the discharge lamp driving unit, and a voltage detection unit configured to detect an inter-electrode voltage of the discharge lamp, in which the controller controls the discharge lamp driving unit so that the driving current includes a hybrid period in which a first period for supplying an AC current with a first frequency to the discharge lamp and a second period for supplying a DC current to the discharge lamp are alternately repeated, in which the first frequency includes a plurality of different frequencies, and in which the controller changes the first frequency on the basis of at least one of the detected inter-electrode voltage and driving power supplied to the discharge lamp.

A discharge lamp lighting device includes a control unit adapted to control a frequency of the AC electric current supplied to a discharge lamp by a feeding unit, in different manners within a first term and a second term which are alternately repeated, the control unit is adapted to control the frequency of the AC electric current such that, within the first term, the frequency of the AC electric current becomes at least one frequency out of plural set frequencies, and is further adapted to control the frequency of the AC electric current, based on a predetermined frequency and an electric current within the previous first term, such that, within the second term, the frequency of the AC electric current becomes a frequency lower than this predetermined frequency.

A discharge lamp driver includes a discharge lamp drive unit that supplies a drive current to the discharge lamp, and a control unit that controls the discharge lamp drive unit according to a drive current waveform, wherein the drive current waveform has a mixed frequency drive period including a unit drive period containing a first drive period in which a first drive current is supplied to the discharge lamp and a second drive period provided immediately after the first drive period, in which a second drive current is supplied to the discharge lamp, the first drive current is a half-period alternating current having a frequency higher than 10 Hz and not higher than 300 Hz, the second drive current is an alternating current having a frequency higher than 1000 Hz, and a length of the second drive period is equal to or longer than a length of the first drive period.

A discharge lamp lighting device includes a control unit adapted to control a frequency of the AC electric current supplied to a discharge lamp by a feeding unit, in different manners within a first term and a second term which are alternately repeated, the control unit is adapted to control the frequency of the AC electric current such that, within the first term, the frequency of the AC electric current becomes at least one frequency out of plural set frequencies, and is further adapted to control the frequency of the AC electric current, based on a predetermined frequency and an electric current within the previous first term, such that, within the second term, the frequency of the AC electric current becomes a frequency lower than this predetermined frequency.

According to an aspect of the invention, a discharge lamp driving device includes a discharge lamp driving section, a control section, and a voltage detecting section. The control section is configured to execute a first discharge lamp driving for executing a first control and a second control for supplying a driving current including a direct current and an alternating current to a discharge lamp. In the first discharge lamp driving, the control section executes the first control when the interelectrode voltage is equal to or smaller than a first threshold voltage at predetermined setting timing and executes the second control when the interelectrode voltage is larger than the first threshold voltage at the predetermined setting timing. A rate of the direct current in the second control is larger than a rate of the direct current in the first control.

A discharge lamp lighting device includes a control unit adapted to control a frequency of the AC electric current supplied to a discharge lamp by a feeding unit, in different manners within a first term and a second term which are alternately repeated, the control unit is adapted to control the frequency of the AC electric current such that, within the first term, the frequency of the AC electric current becomes at least one frequency out of plural set frequencies, and is further adapted to control the frequency of the AC electric current, based on a predetermined frequency and an electric current within the previous first term, such that, within the second term, the frequency of the AC electric current becomes a frequency lower than this predetermined frequency.

A device for providing power to a light arrangement (1) having a current conducting state and a current blocking state. The device comprises a storage circuit (2) with a capacitor (21) coupled to the light arrangement (1) and a resistor (22) located in parallel to the capacitor, a first determination circuit (3) for determining the state of the lighting arrangement, a second determination circuit (4) for, in the current blocking state, determining points of two discharging curves of the storage circuit, a derivation circuit (5) for deriving a condition of the storage circuit, such as life-end, from the discharging curves, a switch circuit (6) comprising an element (61), wherein the switch circuit is configured to switch the element (61) in parallel to the capacitor (21), whereby a first discharging curve is determined with the element being disconnected from the capacitor and a second discharging curve is determined with the element being connected to the capacitor, the capacitor discharging via both the resistor (22) and the element (61). The element (61) may comprise a resistor, a capacitor or an inductor.

A device for providing power to a light arrangement (1) having a current conducting state and a current blocking state. The device comprises a storage circuit (2) with a capacitor (21) coupled to the light arrangement (1) and a resistor (22) located in parallel to the capacitor, a first determination circuit (3) for determining the state of the lighting arrangement, a second determination circuit (4) for, in the current blocking state, determining points of two discharging curves of the storage circuit, a derivation circuit (5) for deriving a condition of the storage circuit, such as life-end, from the discharging curves, a switch circuit (6) comprising an element (61), wherein the switch circuit is configured to switch the element (61) in parallel to the capacitor (21), whereby a first discharging curve is determined with the element being disconnected from the capacitor and a second discharging curve is determined with the element being connected to the capacitor, the capacitor discharging via both the resistor (22) and the element (61). The element (61) may comprise a resistor, a capacitor or an inductor.

There is provide a discharge lamp lighting apparatus that comprises a discharge lamp and a power supply device configured to drive a regular lighting mode and the low electric power lighting mode in a switchable manner. The power supply device configured to control a power supply to the discharge lamp such that, in the low electric power lighting mode, after a secondary protrusion forming process in which an alternating current having a frequency equal to or greater than the basic frequency in the regular lighting mode is supplied, the low electric power lighting mode transitioning to a secondary protrusion maintaining process in which a high frequency alternating current having a frequency higher than the basic frequency in the regular lighting mode, and a low frequency alternating current having a frequency lower than the frequency of the high frequency alternating current is alternately supplied.