CIRCUIT ARRANGEMENT

摘要

The invention relates to a circuit arrangement for operating a lamp comprising: circuit input terminals for connection to a supply voltage source; an inverter coupled to said circuit input terminals for generating an AC voltage with a frequency f out of a supply voltage supplied by the supply voltage source and equipped with inverter output terminals; a piezotransformer comprising transformer input terminals, coupled to the inverter output terminals, and transformer output terminals; terminals for lamp connection coupled to the inverter output terminals; a detector for detecting whether the lamp has ignited. In accordance to the invention the transformer input terminals are connected to the inverter output terminals only by means of passive components and in that the inverter comprises means coupled to the detector for changing the frequency f in response to the ignition of the lamp. As a result the circuit arrangement is simple and inexpensive and need not comprise means for switching the piezotransformer out of the circuit after ignition of the lamp.