+

TLV7081

Lithium

Ion

Battery

PE ASIC

GPIO (

)

1.8V

Regulator

Output

Logic Levels

0V & 1.8V

GPIO (input)

R1

R2

RPU

IN

OUT

REF

VPULL-UP

(V-)

13

TLV7081

www.ti.com

SNOSD69A – MAY 2018 – REVISED JUNE 2018

Product Folder Links: TLV7081

Submit Documentation Feedback

Copyright © 2018, Texas Instruments Incorporated

Typical Applications (continued)

8.2.1.2 Detailed Design Procedure

Instead of being powered directly from the battery, the TLV7081 is powered directly from a voltage reference that

exists in the system. The input to the comparator (IN) is allowed to operate above and below the reference

voltage due to the unique analog front end of the TLV7081. When the battery voltage is above the reference

threshold, the output of the comparator is high and when the battery drops below the threshold of the reference,

the output of the comparator goes low (see Figure 22 for details). For simplicity, the integrated hysteresis of the

comparator is not shown in the timing diagram. Integrated hysteresis is helpful in avoiding glitches at the

comparator output when operating in noisy environments or when the input voltage changes thresholds very

slowly. An open-drain output configuration allows the output logic level of the comparator to be level-shifted to

match the logic level of the receiving device.

8.2.1.3 Application Curve

When the voltage applied to the input pin (IN) falls below the reference threshold (REF), the output pin (OUT) is

pulled low to ground (V-). Moreover, when the input voltage rises above REF, the output of the comparator goes

into a high impedance state and the OUT pin is pulled high by the pull-up resistor and VPULL-UP supply voltage.

Figure 22. Under-Voltage Timing Results

8.2.2 Battery Monitoring in Portable Electronics

A recommended circuit diagram for monitoring a battery voltage in a personal electronic device is shown in

Figure 23. In this diagram, the GPIO pin of an application specific integrated circuit (ASIC) serves as the supply

voltage and the voltage reference for the TLV7081. Using a GPIO pin to power the TLV7081 is possible because

of the low quiescent current of the TLV7081. In systems where power consumption needs to be further reduced,

the GPIO pin can be used to power-cycle the TLV7081.

Figure 23. Battery Monitor