VIN+

VIN-

OUT

V+

GND

VIN+

VIN-

OUT

V+

GND

1

+

INA139

or

INA169

INA139

or

INA169

1N4148

1N4148

10 k

10 k

20 k

Sign

Output

TLV3201

+5 V

5 V

Bus

Voltage

Load

Current

RSH

+/-1 A

Load Curent

1 k

1 k

1 k

1 k

+

Copyright © 2017, Texas Instruments Incorporated

16

INA139, INA169

SBOS181F – DECEMBER 2000 – REVISED FEBRUARY 2017

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Copyright © 2000–2017, Texas Instruments Incorporated

Typical Applications (continued)

8.2.4 Bipolar Current Measurement

The INA139 or INA169 devices can be configured as shown in Figure 15 in applications where measuring current

bi-directionally is required. Two INA devices are required connecting their inputs across the shunt resistor as

shown in Figure 15. A comparator, such as the TLV3201, is used to detect the polarity of the load current. The

magnitude of the load current is monitored across the resistor connected between ground and the connection

labeled Output. In this example the 20-kΩ resistor results in a gain of 20 V/V. The 10-kΩ resistors connected in

series with the INA139 or INA169 output current are used to develop a voltage across the comparator inputs.

Two diodes are required to prevent current flow into the INA139 or INA169 output, as only one device at a time is

providing current to the Output connection of the circuit. The circuit functionality is illustrated in Figure 16.

Figure 15. Bipolar Current Measurement