ADC

LOA D

Microco ntr oller

ENABL E

VS

OUT

GND

IN+

IN±

LOA D

0.1 F

Sup ply Vo ltag e

1.7 V to 5.5 V

GPIO1

GPIO2

ENABL E

VS

OUT

GND

IN+

IN±

0.1 F

Sup ply Vo ltag e

1.7 V to 5.5 V

TI-Device

TM

TI-Device

TM

Bus Voltage1

up to +40 V

Bus Voltage2

up to +40 V

9

INA191

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SLYS020 – FEBRUARY 2019

Product Folder Links: INA191

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Copyright © 2019, Texas Instruments Incorporated

7.4 Device Functional Modes

7.4.1 Normal Operation

The INA191 is in normal operation when the following conditions are met:

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•

•

•

The minimum differential input signal times the gain is greater than the swing to GND (see the Rail-to-Rail

Output Swing section).

During normal operation, this device produces an output voltage that is the gained-up representation of the

difference voltage from IN+ to IN– .

7.4.2 Input Differential Overload

the output as close as possible to the positive supply or ground, and does not provide accurate measurement of

the differential input voltage. If this input overload occurs during normal circuit operation, then reduce the value of

the shunt resistor or use a lower-gain version with the chosen sense resistor to avoid this mode of operation. If a

differential overload occurs in a fault event, then the output of the INA191 returns to the expected value

approximately 80 µs after the fault condition is removed.

7.4.3 Shutdown

The INA191 features an active high ENABLE pin that, when pulled to a logic low signal shuts, down the device.

When shut down, the quiescent current is reduced to 10 nA (typ), and the output goes to a high-impedance state.

The low quiescent current extends the battery lifetime when the current measurement is not needed. When the

ENABLE pin is driven to a logic-high level, the device turns back on. The typical output setting time when

enabled is 130 µs.

The output of the INA191 goes to a high-impedance state when disabled; therefore, it is possible to connect

multiple outputs of the INA191 together to a single ADC or measurement device, as shown in Figure 2.

Figure 2. Multiplexing Multiple Devices With the ENABLE Pin

When connected in this way, enable only one INA191 at a time, and make sure both devices have the same

supply voltage.