| 摘要 |
The invention relates to a circuit arrangement for operating a low-pressure discharge lamp. The circuit arrangement according to the invention comprises means X for supplying the low-pressure discharge lamp, provided with means X1 for generating a current of changing polarity. The circuit arrangement also comprises a feedback network which together with the means X and the low-pressure discharge lamp forms a control loop for controlling a lamp condition parameter. A low-pass filter is included in the control loop. The feedback network is provided with means M for generating a signal m which represents the instantaneous value of the lamp condition parameter, means C for comparing the signal m with a reference signal d, and means S for controlling the means X in dependence on the result of the comparison. The circuit arrangement according to the invention has the characteristic that the control loop has a transfer function with a bandwidth which is small at a comparatively high power consumed by the lamp compared with that at a comparatively low power. Unstable behavior of the control loop is counteracted thereby.
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