Abstract: A wireless control is provided for a lamp, such as a fluorescent lamp, controlled by a ballast with a wireless control interface for RF communication. The receiver input and the transmitter output of the control interface module are connected to one or more electrode wires by a coupling capacitor(s) or a Lecher line transformer. During operation the lamp electrodes serve as the lamp antenna.

Abstract: A communication network includes a plurality of devices and a control unit for generating control signals to control the operation of the devices. Each device includes: a device operating circuit, a communication interface for receiving command signals for controlling operation of the devices, a control circuit coupled between the device operating circuit and the communication interface for controlling the operation of the device operating circuit part in dependency of said command signals, and a master integral to the device for receiving the control signals, for generating the command signals in response to the received control signals, and for transferring the command signals to the communication interfaces of the plurality of devices. The communication network activates one of the masters as an active master, and in case the active master fails, then it activates another master to take over as the active master.

Abstract: A circuit drives an LED array and controls the brightness of the LED array by regulating the current flowing through the array. The LED array is driven by a pulse-shaped current of which the mean value is regulated with at least one or two of the following types of modulation: frequency modulation, pulse-width modulation, and amplitude modulation.

Abstract: A circuit drives an LED array and controls the brightness of the LED array by regulating the current flowing through the array. The LED array is driven by a pulse-shaped current of which the mean value is regulated with at least one or two of the following types of modulation: frequency modulation, pulse-width modulation, and amplitude modulation.

Abstract: The present invention deals with wireless control of a lamp such as a fluorescent lamp controlled by a ballast with a wireless control interface for RF communication. The receiver input and the transmitter output of the control interface module are connected to one or more electrode wires by means of (a) coupling capacitor(s) or a Lecher line transformer. During operation the lamp electrodes serve as the lamp antenna.

Abstract: A fluorescent lamp (2), in particular a backlight lamp of a display device, is supplied with an alternating voltage, a frequency and an amplitude of which being greater during ignition than during normal operation of the lamp. The voltage (V) across the lamp and the current (I) through the lamp are measured to provide a measured voltage value and a measured real lamp current value. From the alternating voltage there is derived a voltage (V2). The measured voltage value is multiplied by the sum of the measured real lamp current value and the derived voltage. The multiplication result (P=V*(I+V2)) is compared with a reference value (Ref), which results in a difference or error value. The error value is used to control the frequency and the amplitude of the alternating voltage (V), such that the error value is minimized.

Abstract: The invention is a new architecture for a high frequency (HF) ballast with wireless communication interface. The new architecture integrates the RF wireless interface into the ballast. A user control transmits an RF control signal to a second antenna at the ballast site which provides the RF signal to the ballast which activates the fluorescent lamp. The ballast includes a transceiver/receiver, a communication decoder, a power control stage and a power stage. The transceiver/receiver receives the RF signal and communicates it to the communication decoder which acts as an interface to the power stage control. The power stage control controls the power stage that activates the fluorescent lamp. The communication decoder, power control stage, power stage and transceiver/receiver are located within the ballast enclosure which is an important part of the invention. If the power stage control is digital it may be combined with the communication decoder into one microprocessor or digital controller such as an ASIC.

Abstract: The invention is a new architecture for a high frequency (HF) ballast with wireless communication interface. The new architecture integrates the RF wireless interface into the ballast. A user control transmits an RF control signal to a second antenna at the ballast site which provides the RF signal to the ballast which activates the fluorescent lamp. The ballast includes a transceiver/receiver, a communication decoder, a power control stage and a power stage. The transceiver/receiver receives the RF signal and communicates it to the communication decoder which acts as an interface to the power stage control. The power stage control controls the power stage that activates the fluorescent lamp. The communication decoder, power control stage, power stage and transceiver/receiver are located within the ballast enclosure which is an important part of the invention. If the power stage control is digital it maybe combined with the communication decoder into one microprocessor or digital controller such as an ASIC.

Abstract: An electronic ballast for operating a lamp with a high-frequency current is equipped with a load branch comprising two LC combinations. The LC combinations are dimensioned such that the shape of the high-frequency current is in between a sine shape and a square-wave shape. The efficacy of a lamp operated by means of the electronic ballast is high, while the RFI generated by the lamp is low.

Abstract: The light output of a lighting arrangement is adjustable at two levels by, for example, “toggling”. During a predetermined time interval immediately after ignition, the lamp is supplied with additional power to heat up. Immediately after stationary conditions have been reached, the light output is automatically adjusted to the lowest of the two levels. During the predetermined time interval, the light output is also controlled so as to be at the lowest of the two levels, so that relatively large changes in the level of the light output during the predetermined time interval, and immediately after it, are prevented.

Abstract: In a ballast circuit for operating a discharge lamp, two different lamp power levels are adjustable. The ballast circuit is equipped with a switch to optimize the amount of power feedback for the lamp power level. This enables total harmonic distortion and power balance to be optimized for more than one power level.

Abstract: An electronic ballast for operating a lamp with a high-frequency current is equipped with a load branch comprising two LC combinations. The LC combinations are dimensioned such that the shape of the high-frequency current is in between a sine shape and a square-wave shape. The efficacy of a lamp operated by means of the electronic ballast is high, while the RFI generated by the lamp is low.

Abstract: In an up-converter comprising two parallel switching elements, the total current through these switching elements is measured using a current sensor consisting of four ohmic resistances, and said total current is controlled so as to be at a constant level. The power dissipation in the current sensor and in the switching elements can be kept at a low level.

Abstract: In a magnetic tape recording system of the type in which the tape is wound helically on a drum and a rotating recording head is provided at the periphery of the drum, auxiliary signals are recorded on separate tracks of the tape before and after it passes the drum. The auxiliary signals are reproduced and compared during playback in order to produce a control signal for controlling the tension of the tape.