7 Detailed Description

7.1 Overview

The INAx191 is a low bias current, 40-V common-mode, current-sensing amplifier with an enable pin. When

disabled, the output goes to a high-impedance state, and the supply current draw is reduced to less than 0.1 µA

per channel. The INAx191 is intended for use in either low-side and high-side current-sensing configurations

where high accuracy and low current consumption are required. The INAx191 is a specially designed, current-

sensing amplifier that accurately measure voltages developed across current-sensing resistors on common-

mode voltages that far exceed the supply voltage. Current can be measured on input voltage rails as high as 40

V, with a supply voltage as low as 1.7 V.

7.2 Functional Block Diagram

IN±

IN+

GND

VS

OUT

+

±

ENABLE

+

±

±

+

INA191

Figure 7-1. INA191 Diagram

IN±1

IN+1

GND

VS

OUT1

+

±

ENABLE1

+

±

±

INA2191

REF1

IN±2

IN+2

OUT2

+

±

ENABLE2

+

±

±

+

REF2

+

Figure 7-2. INA2191 Diagram

INA191, INA2191

SLYS020B – FEBRUARY 2019 – REVISED FEBRUARY 2021

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