A discharge lamp lighting apparatus includes an inverter circuit supplying an AC voltage to a discharge lamp and a resonant circuit that increases a supply voltage supplied to the discharge lamp. The inverter circuit is driven using a first frequency including a resonant frequency of the resonant circuit during a first period in which breakdown and a glow discharge are generated, driven using a second frequency including a resonant frequency of the resonant circuit, lower than the first frequency, during a second period in which an arc discharge is generated, and driven using a third frequency lower than the second frequency, during a third period. Further, a dead time is set in which both of a high-side switching device and a low-side switching device are turned off so that the dead time is longer in the second period than in the first period and the third period.

A discharge lamp driving device includes a discharge lamp driving unit configured to supply driving current to a discharge lamp provided with a first electrode and a second electrode, and a controller configured to control the discharge lamp driving unit. The driving current includes a first AC period and a second AC period in which an AC current is supplied. The first AC period includes a plurality of consecutive first unit driving periods each of which is formed of a first polarity period and a second polarity period, a length of the first polarity period being larger than a length of the second polarity period. The second AC period includes a plurality of consecutive second unit driving periods each of which is formed of the first polarity period and the second polarity period, the length of the second polarity period being larger than the length of the first polarity period.

An xenon lamp power supply, a purification device, and a refrigeration device are provided. The xenon lamp power supply comprises: an input circuit, a coupling assembly, an output circuit, and a control circuit. The input circuit comprises an alternating-current input end and a direct-current output end, and the input circuit is used for converting alternating current input by the alternating-current input end into direct current output by the direct-current output end. A first end of the coupling assembly is connected to the direct-current output end. The output circuit comprises a xenon lamp power supply circuit, and the xenon lamp power supply circuit is connected to a second end of the coupling assembly, so as to convert electric energy from the second end into direct-current power, and then supply power to a xenon lamp.

The lighting device of one aspect according to the present disclosure calculates, based on a voltage value of an AC voltage applied to a discharge lamp and a current value of AC current flowing through the discharge lamp, a first power value defined as a value of power supplied to the discharge lamp in a first half period of the AC voltage and a second power value defined as a value of power supplied to the discharge lamp in a second half period of the AC voltage. The lighting device determines that a ground fault has occurred, when an imbalance state in which a difference between the first power value and the second power value is equal to or greater than a threshold value continues for a predetermined time period.

A discharge lamp lighting apparatus for lighting a discharge lamp in which an electric discharge medium, which contains xenon, is enclosed in an electric discharge container, and a pair of cathode electrode and anode electrode for main discharge is arranged to face each other, comprises a starter for generating dielectric breakdown in the electric discharge container of a discharge lamp, and a power supply circuit for supplying discharge current to the discharge lamp, wherein the power supply circuit has an output current modulation circuit for modulating the magnitude of current passed through the discharge lamp in at least a lighting steady state, according to a modulation signal, and wherein the output current modulation circuit controls speed of change so as to be 2.6 A or less per millisecond in case the magnitude of the lamp current per square millimeter in a cross section of the cathode electrode decreases.

The present disclosure is directed to a method for detecting a failure in a signal light. In one embodiment, the method includes monitoring operation of one or more light emitting diodes (LEDs) of the signal light coupled to a constant current driver, detecting a short circuit in at least one of the one or more LEDs and signaling a failure in the signal light when the short circuit is detected.

Lighting power supply system (1) including a mains input converter (11) operable to provide power, a controller (17) operable to control at least one element of the lighting system, a controller bus (26) and a controller interface (25) operable to provide control signals from the bus to the lighting system. An auxiliary converter (43) powers the lighting system from the bus and it may allow the controller to continue to be powered when the mains input is absent and an emergency battery (19) is depleted.