A method for protecting a step-up/step-down regulator circuit during boost mode operation at a constant clock frequency in which a preset voltage at an output is greater than voltage at an input, the method comprising: connecting an inductor between the input and a common potential in response to each clock signal pulse received; sensing current in the inductor when it is connected to the common potential; in response to the sensed inductor current rising to a current peak threshold level, connecting the inductor between the input and the output; sensing a voltage related to the voltage at the output when the inductor is connected between the input and the output; and connecting the inductor between the common potential and the output prior to a next clock signal pulse in response to occurrence of an output voltage condition, which is a low voltage level or a short circuit, during the voltage sensing step; the method characterised in that: the sensing step comprises subtracting an output feedback voltage from a first voltage reference to obtain a resultant voltage; and the inductor is connected between the common potential and the output when the sensed output related voltage exceeds a second voltage reference; and wherein the sensing step further comprises: adjusting the resultant voltage in accordance with the clock frequency to obtain an adjusted resultant current; and applying the adjusted resultant current to charge a capacitor. connecting an inductor between the input and a common potential in response to each clock signal pulse received; sensing current in the inductor when it is connected to the common potential; in response to the sensed inductor current rising to a current peak threshold level, connecting the inductor between the input and the output; sensing a voltage related to the voltage at the output when the inductor is connected between the input and the output; and connecting the inductor between the common potential and the output prior to a next clock signal pulse in response to occurrence of an output voltage condition, which is a low voltage level or a short circuit, during the voltage sensing step; the method characterised in that: the sensing step comprises subtracting an output feedback voltage from a first voltage reference to obtain a resultant voltage; and the inductor is connected between the common potential and the output when the sensed output related voltage exceeds a second voltage reference; and wherein the sensing step further comprises: adjusting the resultant voltage in accordance with the clock frequency to obtain an adjusted resultant current; and applying the adjusted resultant current to charge a capacitor. the sensing step comprises subtracting an output feedback voltage from a first voltage reference to obtain a resultant voltage; and the inductor is connected between the common potential and the output when the sensed output related voltage exceeds a second voltage reference; and wherein the sensing step further comprises: adjusting the resultant voltage in accordance with the clock frequency to obtain an adjusted resultant current; and applying the adjusted resultant current to charge a capacitor. adjusting the resultant voltage in accordance with the clock frequency to obtain an adjusted resultant current; and applying the adjusted resultant current to charge a capacitor.