Electronic circuit for supplying a high-pressure discharge arc lamp

Abstract

The invention relates to an electronic circuit and to a method of supplying a high-pressure discharge arc lamp (12). The circuit comprises a DC-AC converter, for which purpose two controllable switching elements T1, T2 are connected in the form of a half bridge to an operating potential U+ and a reference potential (10). The circuit further comprises a two-stage filter arrangement. The lamp is connected to a coil Lign of the second filter stage, and the same connection terminal of this coil Lign is connected to the reference potential (10) via a capacitor Cign. To make the circuit as small and as economical as possible, while high high-frequency interference peaks and strong currents in the circuit are avoided, it is proposed that a coil Trfilt of the first filter stage has at least three taps. The first, outer tap is connected to the output of the half bridge, the second, central tap to the second connection terminal of the coil Lign, and the third, outer tap to the reference potential (10) via a capacitor Cfilt.

Description

technical field [0001] The invention relates to an electronic circuit for powering a high pressure discharge arc lamp and a method for operating a high pressure discharge arc lamp with such an electronic circuit. Background technique [0002] High pressure discharge arc lamps are used eg in modern data and video projectors. They are very powerful and are characterized by a particularly short discharge arc. On the basis of the laws of optics, it is possible to make a projector with such a lamp and with a small optical system, which nonetheless has a high luminous efficiency, ie produces a bright image. This results in a significant reduction in the size and cost of the projector. [0003] At the same time, however, new demands are placed on the size and cost of the electronic components of such projectors. The basic electronic component here is the electronic power supply circuit and, in the case of high-pressure discharge arc lamps, also the ballast. [0004] The primary...

AI Technical Summary

Problems solved by technology

This attenuated AC voltage requires a particularly high quality factor for the tuning circuits L2, C2, in connection with which the provision of these components is correspondingly expensive

Moreover, a high voltage and a low AC component are required simultaneously in the lamp during normal operation, resulting in relatively high currents in the circuit

Finally, the described configuration of coils and capacitors may introduce very high frequency interference peaks at least during the ignition phase

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