8.2 Typical Applications

8.2.1 Battery Monitoring using Difference Amplifier

The INA500 is an integrated difference amplifier that processes large differential voltages while simultaneously

rejecting larger common-mode voltages. The device offers a low power consumption of 13.5µA (typical) and has

a smaller form factor.

With the specifications above, the device is a good fit for portable applications that are powered with single

cell or coin-cell batteries. Often, these systems do not need sophisticated battery management technology but

a solution that is rather simple and small-size. In a few other systems, battery monitoring ICs are preferred to

perform sophisticated functions including cell balancing, protection, voltage and current sensing and so forth but

these systems still need a secondary level of protection or redundancy with a simpler and reliable solution for

system integrity. It is in these scenarios, the amplifier based battery monitoring application shown below could be

quite useful.

Figure 8-2 shows an example circuit that monitors a 12V battery voltage and interfaces it to an ADC that is

powered using a 3V power supply. The main advantage for using difference amplifiers in this application is the

elimination of ground bounce, which is a common-mode signal, when measuring the battery voltage. These

ground bounce signals, when not rejected, are capable of causing errors in the range of few milli-volts to tens or

hundreds of milli-volts.

12V

System

Load

GND

Load side

Diagnos cs & Processing

0V

-100mV

12V

11.9V

ILOAD

IGND

+

–

1.68M

V+

OUT

V

IN

IN+

REF

1.68M

0.42M

0.42M

GND2

GND2

ADC

3V

0 to 3V

GND bounce of 100mV is a

common-mode signal which

is rejected by INA500C

INA500C (G = 0.25)

Figure 8-2. Battery Monitoring Circuitry

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INA500

SBOSAI9A – DECEMBER 2023 – REVISED JANUARY 2024

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