R1

VA = VREF

VO High

+VCC

R2

R2

VA = VREF

VO Low

+VIN1

R1

VIN2

Figure 6-6. Non-Inverting Configuration Resistor Networks

When VIN is less than VREF,, the output is low. For the output to switch from low to high, VIN must rise above the

VIN1 threshold. Use Equation 4 to calculate VIN1.

V

= R1

IN1

´

VREF

R2

+ VREF

(4)

When VIN is greater than VREF, the output is high. For the comparator to switch back to a low state, VIN must

drop below VIN2. Use Equation 5 to calculate VIN2.

V

=

IN2

V

REF

CC

(R1 + R2)

V

R1

-

´

R2

(5)

The hysteresis of this circuit is the difference between VIN1 and VIN2, as shown in Equation 6.

DV = V

IN

CC

´

R1

R2

(6)

For more information, see the Inverting comparator with hysteresis circuit application note and the Non-Inverting

Comparator With Hysteresis Circuit application note.

6.1.2.3 Inverting and Non-Inverting Hysteresis using Open-Drain Output

It is also possible to use an open drain output device, such as the TLV1822-EP, but the output pull-up resistor

must also be taken into account in the calculations. The pull-up resistor is seen in series with the feedback

resistor when the output is high. Thus, the feedback resistor is actually seen as R2 + RPULLUP. TI recommends

that the pull-up resistor be at least 10 times less than the feedback resistor value.

6.2 Typical Applications

6.2.1 Window Comparator

Window comparators are commonly used to detect undervoltage and overvoltage conditions. Figure 6-7 shows a

simple window comparator circuit. Window comparators require open drain outputs (TLV1822-EP) if the outputs

are directly connected together.

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TLV1812-EP, TLV1822-EP

SNOSDJ3 – MAY 2024

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