A method for operating a discharge lamp by modulating a current signal is presented. The discharge lamp is operated with at least two different frequencies. At first a probability distribution function for a first number of first frequency periods and a second number of second frequency periods is defined. Next, the first number of first frequency periods and the second number of second frequency periods are determined depending on the probability distribution function by at least one random number. The current signal is modulated by applying the first number of first frequency periods and the second number of second frequency periods to the current signal for operating the discharge lamp.

The invention describes a method for operating a discharge lamp by adapting a current signal. A distribution function is defined for gathering several time span values that define several different time spans. The several time span values are determined depending on the distribution function by one or more random numbers. The current signal is commutated at every instant of time according to an expiry of each of the several time spans. A light apparatus is provided with a control unit to perform any method.

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.

Various embodiments provide a projection arrangement. The projection arrangement may include a discharge lamp; and a ballast for the discharge lamp. The ballast is designed to provide, during operation of the projection arrangement, a lamp current in the form of alternating current and having an average frequency and a preset waveform, which has a preset commutation scheme, to the discharge lamp. The preset commutation scheme is preset by a preset time sequence of commutations of the lamp current. The ballast is designed to provide the lamp current in such a way that the preset commutation scheme of the lamp current is deviated from repeatedly with at least one preset intervening time period by at least one DC phase with a preset time duration.

An input detection and protection circuit and an AC electronic ballast for HID lamps, including a power input circuit performing a first limitation to an input surge voltage and then performing a second limitation to a residual voltage from the first input surge voltage limitation; an input voltage acquisition circuit feeding back an input voltage to an MCU chip; a pull-in circuit for a relay connecting to a relay in the power input circuit; a PFC circuit, and an MCU chip controlling the PFC circuit to switch on and off according to voltage values input by the input voltage acquisition circuit, and controlling pull-in and drop-out of the relay through the pull-in circuit for the relay.

An input detection and protection circuit and an AC electronic ballast for HID lamps, including a power input circuit performing a first limitation to an input surge voltage and then performing a second limitation to a residual voltage from the first input surge voltage limitation; an input voltage acquisition circuit feeding back an input voltage to an MCU chip; a pull-in circuit for a relay connecting to a relay in the power input circuit; a PFC circuit, and an MCU chip controlling the PFC circuit to switch on and off according to voltage values input by the input voltage acquisition circuit, and controlling pull-in and drop-out of the relay through the pull-in circuit for the relay.

A discharge lamp drive device includes a discharge lamp driver adapted to supply a drive current to a discharge lamp having a first electrode and a second electrode, 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 plurality of drive patterns has a plurality of drive parameters. The control section executes at least three of the drive patterns in a case in which drive power to be supplied to the discharge lamp is in a predetermined power band, and in a case in which an inter-electrode voltage of the discharge lamp is a predetermined voltage value. Any two of the at least three drive patterns are different from each other in a value of at least one of the plurality of drive parameters.

A discharge lamp drive device includes a discharge lamp driver adapted to supply a drive current to a discharge lamp having a first electrode and a second electrode, 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. The control section is adapted to select one drive pattern of the plurality of drive patterns based on machine learning, and execute the selected drive pattern.

An input detection and protection circuit and an AC electronic ballast for HID lamps, including a power input circuit performing a first limitation to an input surge voltage and then performing a second limitation to a residual voltage from the first input surge voltage limitation; an input voltage acquisition circuit feeding back an input voltage to an MCU chip; a pull-in circuit for a relay connecting to a relay in the power input circuit; a PFC circuit, and an MCU chip controlling the PFC circuit to switch on and off according to voltage values input by the input voltage acquisition circuit, and controlling pull-in and drop-out of the relay through the pull-in circuit for the relay.

An input detection and protection circuit and an AC electronic ballast for HID lamps, including a power input circuit performing a first limitation to an input surge voltage and then performing a second limitation to a residual voltage from the first input surge voltage limitation; an input voltage acquisition circuit feeding back an input voltage to an MCU chip; a pull-in circuit for a relay connecting to a relay in the power input circuit; a PFC circuit, and an MCU chip controlling the PFC circuit to switch on and off according to voltage values input by the input voltage acquisition circuit, and controlling pull-in and drop-out of the relay through the pull-in circuit for the relay.