Patent ID: 7242154

Claim:
A circuit arrangement for operation of lamps (Lp) having the following features: a half-bridge arrangement which has an upper and a lower electronic switch (S 1 , S 2 ) which are connected in series, each have a control connection and form a central point (N 1 ) at their junction point, a load circuit (Lk), in which a load current (IL, WavIL) flows, is connected to the central point (N 1 ), the load circuit (Lk) contains a reactance network with a resonant frequency, to which a lamp (Lp) is connected, the load circuit (Lk) is designed such that, during normal operation for a connected lamp (Lp) and after opening of one electronic switch (S 1 , S 2 ), the voltage across the respective other electronic switch (S 1 , S 2 ) becomes zero after a ringing time, the circuit arrangement has a feedback device (Rk), which couples a feedback variable from the load circuit (Lk) to the control connections of the electronic switches (S 1 , S 2 ) in such a way that the electronic switches (S 1 , S 2 ) are switched on alternately, the circuit arrangement has a stop device (St) which is coupled to the control connections of the electronic switches (S 1 , S 2 ) and has one input to which a stop signal is applied, with the stop device (St) preventing the electronic switches from being switched on for as long as the stop signal (Wav 2 ) is in the off state, the circuit arrangement has a timer (Ti) which is coupled to the input of the stop device (St) and produces the stop signal (Wav 2 ), which can assume an on state and the off state, and the circuit arrangement has a trigger device (Tr) which in each case emits a trigger signal (Wav 1 ) to the timer (Ti) after the ringing time has elapsed, but at the latest when the load current (IL, WavIL) becomes zero, wherein the timer (Ti) switches the stop signal (Wav 2 ) to the on state if it receives the trigger signal (Wav 1 ) and retains the on state for the duration of an on time.