A method of limiting an input or output current (Iin, Iout) of a DC to DC converter controlled by a control signal (CTRL'), the control signal controlling the level of an output voltage of the DC to DC converter, the method comprising: - setting first and second values (VMAX, VMIN) to a value representing a current level of the output voltage; - in response to the input or output current (Iin, Iout) exceeding a first threshold (Ith), modifying the control signal (CTRL') in order to step down the output voltage of the converter until the input or output current (Iin, Iout) no longer exceeds the first threshold (Ith), and storing as the first value the value of the control signal (CTRL') when the input or output current (Iin, Iout) exceeded the first threshold (Ith), the first value being representative of the level of the output voltage (Vout) of the DC to DC converter, and in response to the input or output current (Iin, Iout) falling below the first threshold (Ith) or a further threshold, modifying the control signal (CTRL') in order to step up the output voltage of the converter until the input or output current (Iin, Iout) exceeds the first threshold (Ith) or further threshold, and storing as the second value the value of the control signal (CTRL') when the input or output current (Iin, Iout) fell below the first or further threshold, the second value being representative of the level of the output voltage (Vout); and - modifying the control signal (CTRL') to a value between the first and second values (VMAX, VMIN) to bring the output voltage (Vout) to an intermediate voltage level (Vint) between the level of the output voltage (Vout) represented by the first value and the level of the output voltage (Vout) represented by the second value. - setting first and second values (VMAX, VMIN) to a value representing a current level of the output voltage; - in response to the input or output current (Iin, Iout) exceeding a first threshold (Ith), modifying the control signal (CTRL') in order to step down the output voltage of the converter until the input or output current (Iin, Iout) no longer exceeds the first threshold (Ith), and storing as the first value the value of the control signal (CTRL') when the input or output current (Iin, Iout) exceeded the first threshold (Ith), the first value being representative of the level of the output voltage (Vout) of the DC to DC converter, and in response to the input or output current (Iin, Iout) falling below the first threshold (Ith) or a further threshold, modifying the control signal (CTRL') in order to step up the output voltage of the converter until the input or output current (Iin, Iout) exceeds the first threshold (Ith) or further threshold, and storing as the second value the value of the control signal (CTRL') when the input or output current (Iin, Iout) fell below the first or further threshold, the second value being representative of the level of the output voltage (Vout); and - modifying the control signal (CTRL') to a value between the first and second values (VMAX, VMIN) to bring the output voltage (Vout) to an intermediate voltage level (Vint) between the level of the output voltage (Vout) represented by the first value and the level of the output voltage (Vout) represented by the second value.