Circuit arrangement and signalling light provided with the circuit arrangement

A circuit for operating a semiconductor light source comprising:

• input terminals for connection to a control unit,
• an input filter coupled to the input terminals,
• a converter including a control circuit and having output terminals for connection to the semiconductor light source in order to energize the semiconductor light source,
• means CM including a controlled semiconductor element for removing a leakage current occurring in the control unit in the non-conducting state, said means CM having an input coupled to the input filter and an output coupled to the converter,
• self-regulating deactivating means for deactivating the means CM when the control unit is in a conductive state, and
• detection means for detecting a defective converter or semiconductor light source connected thereto.