´

Power Register

Current Register

I C

2

Interface

Voltage Register

GND

BUS

ADC

V

I

A0

ALERT

A1

SDA

SCL

C

0.1 F

BYPASS

m

10A

Load

Alert Register

V

(Supply Voltage)

S

+12-V Supply

IN-

IN+

R

2 m

SHUNT

W

30

INA231

SBOS644B – FEBRUARY 2013 – REVISED AUGUST 2017

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Copyright © 2013–2017, Texas Instruments Incorporated

9.2 Typical Applications

Figure 29. Monitoring a 10-A Load

9.2.1 Design Requirements

through the resistor. The device also measures the bus supply voltage, and calculates power when calibrated.

The INA231 comes with alert capability, where the alert pin can be programmed to respond to a user-defined

event, or to a conversion-ready notification. This design illustrates the ability of the alert pin to respond to a set

threshold. In this case, a 10 A are pulled through a 2-mΩ shunt resistor, generating a 20-mV shunt voltage drop

that is measured by the INA231. The bus supply is 12 V, and the BUS pin is tied to the IN– pin, so that the

power loss through the shunt resistor, however small, is not added to the power calculation performed by the

INA231. This configuration provides an accurate measurement the power dissipated by the load.

9.2.2 Detailed Design Procedure

The ALERT pin can be configured to respond to one of the five alert functions described in the ALERT Pin

section. The ALERT pin must to be pulled up to the VS pin voltage using a pull-up resistor. The Configuration

register is set based on the required conversion time and averaging. The Mask/Enable register is set to identify

the required alert function and the Alert Limit register is set to the limit value used for comparison.

9.2.3 Application Curves

and averaging set to 1. Figure 31 shows the response for the same limit, but with the conversion time reduced to

1.1 ms.