Time (4 ms/div)

Output

Inputs

INA282, INA283, INA284, INA285, INA286

SBOS485C – NOVEMBER 2009 – REVISED MAY 2015

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Typical Applications (continued)

8.2.1.1 Design Requirements

In order to sum multiple load currents, multiple INA28x devices must be connected. Figure 40 shows summing

for two devices. Summing beyond two devices is possible by repeating this connection. The reference input of

the first INA28x family device sets the output quiescent level for all the devices in the string.

8.2.1.2 Detailed Design Procedure

Connect the output of one INA28x family device to the reference input of the next INA28x family device in the

chain. Use the reference input of the first circuit to set the reference of the final summed output. The currents

sensed at each circuit in the chain are summed at the output of the last device in the chain.

8.2.1.3 Application Curves

An example output response of a summing configuration is shown in Figure 41. The reference pins of the first

circuit are connected to ground, and sine waves at different frequencies are applied to the two circuits to produce

a summed output as shown. The sine wave voltage input for the first circuit is offset so that the whole wave is

above GND.

VREF = 0 V

Figure 41. Current Summing Application Output Response

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