One example discloses a current monitoring device, including: a sense impedance configured to receive a current to be monitored; an impedance divider, coupled to the sense impedance, and configured to convert the current to be monitored to a differential voltage to be monitored; a reference circuit configured to generate a differential reference voltage; a comparator coupled to the impedance divider and the reference circuit and configured to output a signal if the differential voltage to be monitored is different than the differential reference voltage; and wherein the reference circuit includes a comparator trimming circuit configured to vary the differential reference voltage to compensate for offset biases in the comparator.