摘要:
An improved high frequency ballast is disclosed. The high frequency ballast establishes a lamp current for a gas discharge lamp during a starting operation of the gas discharge lamp wherein an operating ampere level of the lamp current facilitates a substantial achievement by the gas discharge lamp of a color specification associated with the gas discharge lamp. Thereafter, during a stable operation of the gas discharge lamp, the high frequency ballast applies a frequency modulation to an operating frequency of the lamp current and/or an amplitude modulation of the lamp current.
摘要:
A circuit arrangement for igniting and operating a high-pressure discharge lamp includes input terminals for the connection of a supply source and output terminals for the connection of the lamp. A switching circuit operates the lamp at a nominal lamp voltage Vla during stable lamp operation and generates an open circuit voltage Vo at the output terminals before the lamp is ignited. A control circuit for controlling the switching circuit is provided with a device BM for limiting the voltage at the output terminals. A transition detection circuit M detects the transition from a glow discharge to an arc discharge.
摘要:
A circuit arrangement for igniting and operating a discharge lamp is provided with input terminals for connecting a supply source, and a ground terminal, differential-mode and common-mode filters in which inductance and capacitance are incorporated, output terminals for connecting the discharge lamp, and a switch mode power supply connected to the input terminals and the output terminals by respective voltage conduction branches. The circuit arrangement is characterized in that the input terminals and output terminals are connected both to one another and to the ground terminal by respective capacitive filters, in that a bead is included in one of the voltage conduction branches, and in that further common-mode capacitance is present between the inductance and the switch mode power supply. The requirements formulated in both EN55022 and EN55015 can be complied with in this manner.
摘要:
A high pressure gas discharge lamp system includes a high pressure discharge lamp selected to have a lowest lamp resonant frequency above the audible, on a current basis above about 19 kHz and on a power basis of above about 38 kHz. The ballast circuit energizes the discharge device so as to have a fundamental frequency below the lowest lamp resonant frequency and above the audible, while keeping the magnitude of any harmonics above the lowest lamp resonant frequency sufficiently small so as to avoid acoustic resonance. By operating below the lowest lamp resonant frequency, greatly simplifying ballast construction and cost. According to one embodiment, the discharge vessel encloses a discharge space which is circular cylindrical and having a L:ID ratio of about 1:1 to maximize the lowest lamp resonant frequency. According to another embodiment, two or more discharge devices are operated concurrently by the ballast, each having a lowest lamp resonant frequency of above the audible, and the ballast operating frequency so as to increase light output while still avoiding acoustic resonance.