AN4071 datasheet(24/27 Pages) STMICROELECTRONICS

24 / 27 page

Window comparator

AN4071

24/27

Doc ID 022939 Rev 1

Window comparator

The window comparator is a circuit utilizing two single open drain /collector comparators

operating together. It has three inputs. Two of them are dedicated for reference voltage and

one for signal input. Figure 27 illustrates the function of the window comparator. Output is

high (VOUT = VPULL) when input voltage lies above VTH- and below VTH+, otherwise the

output is low (0 V).

Figure 27.

Window comparator

Figure 28.

Temperature control circuit

An example of the window comparator application represents a simple temperature

controller circuit (Figure 28). Based on the TS332 dual comparator and temperature sensor

STLM20, the circuit monitors if the temperature holds in the required range (25

± ~10 °C).

The STLM20 is a precision analog output temperature sensor for low current applications.

The maximum temperature accuracy of the STLM20 is ± 1.5 °C (typ. ±0.5 °C) at ambient

temperature of 25 °C and VCC of 2.7 V. The STLM20 has a maximum quiescent supply

current of 8

μA, therefore self-heating is negligible.

AN4071 Fiches technique(PDF) 24 Page - STMicroelectronics