| 摘要 |
In the method a stabilized phase regime (Ps) has at least an operating point for which the average intensity (Imoy2) of the luminous flux is different from the nominal flux so as to produce a second lighting effect. To switch from one operating point to another an electronic unit (20) modifies the duration of each time interval (IT) between a positive and negative voltage pulse and/or modifies the duration (D) of each voltage pulse if they are separated by a non null time interval (IT). Method of control fro an a.c. supply (10) feeding a discharge lamp (12), of the type in which the supply is fed from a d.c. voltage source (Ue) and has a d.c. to a.c. converter (16) having switches which are driven by an electronic unit which in a first time period, controls the operation of the supply (10) in a lamp firing phase (Pa) and during a second period, controls the supply in a stabilized regime (Ps) having a first operating point for which the lamp produces an set luminous flux of average intensity (Imoy1) for illuminating the road. The supply voltage (Ua) in the stabilized regime (Ps) has alternative positive and negative pulses. To switch to the first operating point from another point, the electronic unit increases the duration of each time interval (IT) and/or reduces the duration (D) of each voltage pulse so that the lamp produces an average light flux intensity (Imoy2) less than nominal flux (Imoy1).
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