A switched-mode power supply includes: a switching converter converts an input voltage into an output voltage in accordance with a switching signal, wherein the switching converter includes a transformer providing galvanic isolation between a primary side and a secondary side of the switching converter; and a wake-up circuit connected to the secondary side of the switching converter, the wake-up circuit coupled to the secondary side of the switching converter and operable to generate a feedback signal that indicates whether the output voltage is greater than or equal to a threshold value. A primary side regulator generates a control signal depending on a reference value and a measured value (VAUX) representing the output voltage. Primary side logic generates the switching signal depending on the control signal. A tracking unit receives the feedback signal via a galvanically isolating component and adjusts the reference voltage based on the feedback signal.