An operating circuit for energizing a lamp (5) comprising at least one light emitting diode (6) has a primary side (11) and a secondary side (12) that is electrically isolated from the primary side. The operating circuit comprises a clocked converter (14) that has a primary coil and a secondary coil (18). The operating circuit further comprises a detection device (20) for determining an output voltage (Vout) of the operating circuit; the detection device (20) comprises an inductor (21) which is located on the primary side (11) of the operating circuit and which is inductively coupled to the secondary coil (18).
