Control circuits (1) bring power converters (4) in different modes in response to detection results. The power converters (4) exchange possibly rectified first voltage/current signals with electronic halogen transformers (2) and supply second voltage/current signals to light emitting diode circuits (5). The first current signals have, in different modes, different amplitudes. The different amplitudes have different constant values and/or different derivative values. As a result, the first current signal has become a relatively varying first current signal. Then, the halogen transformers (2) no longer experience problems that occur when smaller amounts of power need to be provided than designed to. The detections may comprise polarity detections of and/or zero-crossing detections in the first voltage signals. The halogen transformers (2) comprise self-oscillating switched mode power supplies designed to provide first amounts of power at their outputs. The light emitting diode circuits 5) are designed to consume second amounts of power smaller than the first amounts.