Abstract: According to the invention, a state automaton is used when operating a high-pressure discharge lamp on a ballast operated by means of a microprocessor in order to prevent certain malfunctions.

Abstract: The invention relates to an electronic ballast and to an operating method for high-pressure discharge lamps. During a current measurement, in particular for current regulation, only switching phases of a specific polarity of the current are taken into consideration.

Abstract: An electronic control gear for a HID lamp receives an input signal for operating the lamp and frequency modulates the input signal to generate a frequency modulated output signal that drives an arc of the lamp. The frequency modulation of the output signal sweeps continuously between a low frequency modulation and a high frequency modulation, the low frequency modulation being a frequency f1 in a range of 125 kHz to 150 kHz and the high frequency modulation being a frequency f2 in a range of 230 kHz to 300 kHz, where f2-f1 is at least 0.4*f1. A power amplifier changes an amplitude of the frequency modulated output signal during the low frequency modulations so that a current amplitude of the frequency modulated output signal is substantially constant, and a variable gain transformer adjusts a voltage of the frequency modulated output signal during starting of the lamp.

Abstract: A step-up converter has a power factor correction, has an input for connection to a supply voltage, in particular a rectified AC voltage; an inductor, a diode and a storage capacitor, which are coupled in a series arrangement between the input and the output, in which the voltage that is dropped across the storage capacitor is provided at the output; a switch, which is coupled between a junction point between the inductor and the diode, on the one hand, and a reference potential, on the other hand; and a drive circuit for the switch which controls the times for which the switch remains closed and open; the drive circuit being designed to control the time for which the switch remains closed as a function of the freewheeling time of the inductor. A method for operating such a step-up converter is also disclosed.

Abstract: A ballast for at least one electric incandescent lamp, having at least two switching elements (T1, T2) that are coupled to one another with the formation of a first tie point (VP1), a drive circuit (10) with at least one output for driving the switching elements (T1, T2) with the aid of a drive signal that has a pulse duty factor (d) and an operating frequency (fs), and with an input for a dimming signal (Ud), and a power transformer (Ü) whose primary side (L1) is coupled to the first tie point (VP1), it being possible to connect the electric incandescent lamp (LA1; LA2) to the secondary side (L2) thereof, the drive circuit (10) being designed to vary the pulse duty factor (d) and the operating frequency (fs) of the drive signal as a function of the dimming signal (Ud).

Abstract: Electronic transformers with a self-excited half bridge can be destroyed by high-voltage pulses from the mains supply lead. This can happen by the high-voltage pulse initiating a starting operation which leads to cross currents. This destruction mechanism is suppressed by specifically discharging a starting capacitor.

Abstract: The present invention relates to a ballast for at least one electric incandescent lamp, having at least two switching elements (T1, T2) that are coupled to one another with the formation of a first tie point (VP1), a drive circuit (10) with at least one output for driving the at least two switching elements (T1, T2) with the aid of a drive signal that is characterized by a pulse duty factor (d) and an operating frequency (fs), and with an input for a dimming signal (Ud), and a power transformer (Ü) whose primary side (L1) is coupled to the first tie point (VP1), it being possible to connect the at least one electric incandescent lamp (LA1; LA2) to the secondary side (L2) thereof, the drive circuit (10) being designed to vary the pulse duty factor (d) and the operating frequency (fs) of the drive signal as a function of the dimming signal (Ud). Furthermore the invention relates to a corresponding method.

Abstract: Electronic transformers with a self-excited half bridge can be destroyed by high-voltage pulses from the mains supply lead. This can happen by the high-voltage pulse initiating a starting operation which leads to cross currents. This destruction mechanism is suppressed by specifically discharging a starting capacitor.