The present disclosure relates to an interface comprising: a terminal for delivering a DC voltage; a comparator for delivering a first signal representative of a comparison of the DC voltage with a high threshold; a comparator for delivering a second signal representative of a comparison of the DC voltage with a low threshold; and a circuit configured to: deliver successive pairs of values of high and low thresholds for a time period after the DC voltage crosses a first value of the low threshold; modify successive pairs of values of the thresholds based on the first and second signals to determine values of thresholds surrounding the DC voltage; and determining a current value of the DC voltage based on the values of thresholds surrounding the DC voltage.