摘要:
The present invention relates to an electronic ballast for discharge lamps (LA) which have preheatable electrodes (E1, E2). The electronic ballast has a measuring apparatus (M), which is designed to measure, during the preheating process, a variable, which is correlated with the electrode temperature increased by the preheating, of at least one of the electrodes (E1, E2) of a connected discharge lamp (LA), and a control apparatus (C), which is designed to match the electrode temperature, during the preheating process, in response to the measurement by adjusting an operational parameter of the electronic ballast. Furthermore, the electronic ballast is designed to detect cross discharges or a sufficient operating temperature of one of the electrodes (E1, E2) and possibly to ignite the discharge.
摘要:
The drive signal for a switchable heating transformer of an electronic ballast should be capable of being produced in a simple manner. For this purpose, the invention provides for an oscillating inverter voltage, which has a variable inverter frequency, to be tapped off, for example, at the half-bridge center point. The inverter frequency is then preferably converted into a drive signal by a charge pump (C1, C2, D1, D2). As a function of this drive signal, the heating transformer (HT) is switched. Synchronization with externally controlled sequence control of the electronic ballast is therefore also possible.
摘要:
In various embodiments, a circuit for driving a fluorescent lamp is provided. The circuit may include a half bridge including a first switch and a second switch; a drive unit for driving the first switch and the second switch, it being possible for a predetermined state to be established using the drive unit, and it being possible for the driving of the first and the second switch to be modulated as a result of the predetermined state using the drive unit.
摘要:
The invention relates to a method for the provision of operator-specific performance features of different mobile radio network operators for a mobile radio customer, whereby the mobile radio customer has a smart card, on which a user relationship for the mobile radio customer with a mobile radio network operator is stored. The method is characterized in that at least two user relationships are defined on the smart card of the mobile radio customer with differing mobile radio call numbers and with independent performance features and a mobile radio network operator is assigned to each user relationship.
摘要:
In a circuit arrangement for operating light sources, inexpensive technologies for power factor correction can be used in combination. Owing to the combination of a dual charge pump and a valley fill circuit it is also possible to adhere to relevant standards for rated current harmonics even at rated powers of over 25 W whilst maintaining low component loading.
摘要:
An apparatus for operating a plurality of discharge lamps is to be designed so as to be more cost-effective. A first current control device, in particular a heat-sensitive resistor having a positive temperature coefficient, is connected in parallel with a first contact device for electrically connecting a first discharge lamp. Furthermore, a second contact device for electrically connecting a second discharge lamp is connected in parallel with a second current control device, the first and second contact devices being connected in series. A defined preheating period for the lamps can therefore be achieved. By using a sequential starting capacitor in parallel with one of the lamps, impermissible load current surges may be avoided.
摘要:
The invention relates to a method for renewing program files of a programmable, mobile telecommunications terminal, according to which the program files are transmitted from a telecommunications network to the telecommunications terminal via the air interface. The aim of the invention is to allow the program files to be renewed in a simple and cost-effective manner and with little effort. To achieve this, the terminal type is determined by the telecommunications network, new program files that exist in devices of the telecommunications network, or are available elsewhere are determined and made available for the identified terminal type and the existing new program files are automatically transmitted to the terminal via the air interface.
摘要:
In the case of circuit arrangements for operating gas-discharge lamps (Lp), a charge pump (D5, D6, C31, C32) is often used for the purposes of power-factor correction. If this is the case, poorly igniting lamps (Lp) experience an increase in voltage across a storage capacitor (C1). This is avoided according to the invention by a PTC (KL) in parallel with diodes (D5, D6) of the charge pump.
摘要:
A circuit arrangement for high-frequency operation of a low-pressure discge lamp (18) includes a mains rectifier (10), a radio interference suppression filter (12) connected to the mains rectifier (10), an RF inverter (14), connected to the direct current output of the mains rectifier (10) and having two alternatingly switching transistors (T.sub.1, T.sub.2) along with an inductance (L.sub.K), a trigger circuit and a center tap (M), which is between the two transistors (T.sub.1, T.sub.2). A filter capacitor (C.sub.S) is connected parallel to the switching paths of the two transistors (T.sub.1, T.sub.2) of the RF inverter (14). A series resonant circuit (16) is assigned to the low-pressure discharge lamp (18), and comprises a resonant inductance (L.sub.3), a coupling capacitor (C.sub.3), and a resonant capacitance parallel to the lamp. The connection lines for the low-pressure discharge lamp (18) lead on the one hand from a first electrode (E.sub.1) via the resonant inductance (L.sub.3) to the center tap (M) and on the other from a second electrode (E.sub.2) via the center tap of a diode series circuit, connected in the direct current forward direction in series with the filter capacitor (C.sub.S) and comprising a first and a second diode (D.sub.1, D.sub.2), to the positive and negative terminal, respectively, of the mains rectifier (10). The capacitance parallel to the lamp of the series resonant circuit (16) assigned to the low-pressure discharge lamp (18) comprises two parallel-connected capacitors (C.sub.R1, C.sub.R2); one (C.sub.R2) of the capacitors (C.sub.R1, C.sub.R2) parallel to the lamp is connected directly to the positive or negative terminal of the filter capacitor (C.sub.S).