INA231 datasheet(10/44 Pages) TI1

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ADC

Shunt Voltage

Channel

Bus Voltage

Channel

Shunt Voltage

(1)

Data Registers

Calibration

(2)

Current

(1)

Bus Voltage

(1)

Power

(1)

INA231

SBOS644B – FEBRUARY 2013 – REVISED AUGUST 2017

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8 Detailed Description

8.1 Overview

The INA231 is a digital, current-sense amplifier with an I2C- and SMBus-compatible interface. It provides digital

current, voltage, and power readings necessary for accurate decision-making in precisely controlled systems.

Programmable registers allow flexible configuration for measurement resolution, as well as continuous-versus-

triggered operation. Detailed register information is shown in the Register Maps section. See the Functional

Block Diagram section for a block diagram of the INA231 device.

8.2 Functional Block Diagram

(1)

Read-only

(2)

Read/write

Figure 20. Functional Block Diagram

8.3 Feature Description

8.3.1 Basic Analog-to-Digital Converter (ADC) Functions

The INA231 performs two measurements on the power-supply bus of interest. The voltage developed from the

load current that flows through a shunt resistor creates the shunt voltage signal that is measured at the IN+ and

IN– pins. The device can also measure the power supply bus voltage by connecting this voltage to the BUS pin.

The differential shunt voltage is measured with respect to the IN– pin whereas the bus voltage is measured with

respect to ground.

The INA231 is typically powered by a separate supply that can range from 2.7 V to 5.5 V. The bus that is being

monitored can range in voltage from 0 V to 28 V.

NOTE

Based on the fixed 1.25 mV LSB for the bus voltage register, a full-scale register would

result in a 40.96-V value. However, the actual voltage that is applied to the input pins of

the INA231 should not exceed 28 V.

There are no special considerations for power-supply sequencing because the common-mode input range and

power-supply voltage are independent of each other; therefore, the bus voltage can be present with the supply

voltage off, and vice-versa.

As noted, the INA231 takes two measurements, shunt voltage and bus voltage. It then converts these

measurements to current, based on the Calibration register value, and then calculates power. See the Configure,

Measure, and Calculate Example section for additional information on programming the calibration register.

INA231 Datasheet(PDF) 10 Page - Texas Instruments

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