A method and the related circuit protect against malfunctioning of the feedback loop in switching power supplies. More particularly, the circuit identifies a condition of excessively high voltage at the output. In one embodiment the circuit for the protection against malfunctioning of the feedback loop of a switching power supply comprises: circuitry that generates a voltage proportional to the output voltage of the switching power supply; a comparator for comparing the voltage proportional to the output voltage with a reference voltage; a counter coupled to the comparator and capable of supplying an output signal when said voltage proportional to the output voltage exceeds said reference voltage a threshold number of times; said output signal is indicative of a malfunctioning of the feedback loop.