The comparator has two thresholds and the transmission characteristics curve is windowed, so it is called a window comparator.

The automotive-qualified AMC23C15-Q1 dual-window comparator provides a high level of galvanic isolation, thus easing system design as well as achieving the needed certification to regulatory mandates.

The following automatic battery-charger design is created with a circuit that could qualify as the simplest window comparator ever built around a single transistor (see the figure).