8.2.1.1 Design Requirements

In many applications such as industrial alarms, sensor monitors, and level sensors, there is a need to make a decision at the system-level when the input signal crosses a predefined threshold. Analog window comparators are being used extensively in such applications.

An analog window comparator has a set of comparators. The external input signal is connected to the inverting terminal of one comparator and the noninverting terminal of the other comparator. The remaining input of each comparator is connected to the internal reference. The outputs are tied together and are often connected to a reset or general-purpose input of a processor (such as a digital signal processor, field-programmable gate array, or application-specific integrated circuit) or the enable input of a voltage regulator (such as a DC-DC or low-dropout regulator). Figure 112 shows the circuit diagram for an analog window comparator.

Though analog comparators are easy to design, there are certain disadvantages associated with analog comparators.