The invention relates to an electronic tripping device power supply circuit arrangement especially for low or medium voltage over-current tripping devices. The current transformer comprises a voltage transformer (SPW) providing the tripping devices with a second auxiliary power supply (UH2) when current is lacking or relatively low current is present, and a voltage transformer (STW) providing the tripping devices with a first auxiliary power supply (UH1) when current is high. A second voltage transformer (SR2) to produce the second auxiliary power supply (UH2) is placed downstream from the voltage transformer (STW) and both auxiliary power supplies (UH1, UH2) are transmitted to a common auxiliary power supply connection (UH) by a diode decoupling device (DE). Such circuits are used to supply power to low and medium voltage over-current tripping devices.