Patent ID: 7280375

Claim:
A circuit arrangement for operating at least one light-emitting diode (LED) in an electrical circuit at a service voltage (UB), which is greater than the forward voltage of the at least one light-emitting diode (LED) which is to be operated, wherein adjustment of a current flowing through the light-emitting diode (LED) is performed by means of pulse-width modulation of a first switching means (S 1 ), which is switched between a first terminal of the service voltage (UB) and the light-emitting diode LED, wherein between the first terminal of the service voltage (UB) and the at least one light-emitting diode (LED) a first reactance formed by a first resistance (R 1 ) and a first capacitor (C 1 ) is arranged, characterized in that the at least one light-emitting diode (LED) is connected via a second reactance formed by a second resistance (R 2 ) and a second capacitor (C 2 ) to a second terminal of the service voltage, between the two connections of the at least one light-emitting diode (LED) and the two reactances (R 1 -C 1 , R 2 -C 2 ) a full-wave rectifier diode bridge of four diodes (D 1 , D 2 , D 3 , D 4 ) being switched, and at a tap between the first switching means (S 1 ) and the at least one light-emitting diode (LED) a connection, switchable via a second switching means (S 2 ), to the second terminal of the service voltage exists, the second switching means (S 2 ) being operated in push-pull action to the first switching means (S 1 ).