The invention relates to a circuit arrangement (1) for controlling at least one load (D1, D2, D3). In order to provide means for extracting an auxiliary power supply from a current source in order to control shunt switching, the inventive circuit arrangement (1) comprises an input terminal (11) for connection to a power supply (30), an output terminal (12) for connection to at least one load element (20, 21, 22, 23), a control circuit (10), comprising a control device (13), which is adapted to control at least one load element (20, 21, 22, 23), and an energy storage device (C), which is adapted to supply power to the control device (13). A controllable bypass switch (M4) is further provided, wherein said bypass switch (M4) and said control circuit (10) are connected in parallel and are connected between said input terminal (11) and said output terminal (12). The circuit arrangement (1) is adapted to operate the bypass switch (M4) to control the power provided to the control circuit.