INA210 datasheet(17/50 Pages) TI2

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7.4.2 Multiple Channel Monitoring

The INA3221 monitors shunt and voltage measurements for up to three unique power-supply rails, and

measures up to six different signals. Adjust the number of channels and signals being measured by setting

the channel enable (CH1en to CH3en) and mode (MODE3-1) bits in the Configuration register. This adjustment

allows the device to be optimized based on application requirements for the system in use.

7.4.2.1 Channel Configuration

If all three channels must be monitored at power-up, but only one channel must be monitored after the system

has stabilized, disable the other two channels after power-up. This configuration allows the INA3221 to only

monitor the power-supply rail of interest. Disable unused channels to help improve system response time by

more quickly returning to sampling the channel of interest. The INA3221 linearly monitors the enabled channels.

That is, if all three channels are enabled for both shunt- and bus-voltage measurements, an additional five

conversions complete after a signal is measured before the device returns to that particular signal to begin

another conversion. To reduce this requirement down to two conversions before the device begins a new

conversion on a particular channel again, change the operating mode to monitor only the shunt voltage.

A timing aspect is also involved in reducing the measured signals. The amount of time to complete an all-

channel, shunt- and bus-voltage sequence is equal to the sum of the shunt-voltage conversion time and the

bus-voltage conversion time (programmed by the CT bits in the Configuration register) multiplied by the three

channels. The conversion times for the shunt- and bus-voltage measurements are programmed independently;

however, the selected shunt- and bus-voltage conversion times apply to all channels.

Enable a single channel with only one signal measured to allow for that particular signal to be monitored solely.

This setting enables the fastest response over time to changes in that specific input signal because there is no

delay from the end of one conversion before the next conversion begins on that channel. Conversion time is not

affected by enabling or disabling other channels. Selecting both the shunt- and bus-voltage settings, as well as

enabling additional channels, extends the time from the end of one conversion on a signal before the beginning

of the next conversion of that signal.

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INA3221

SBOS576C – MAY 2012 – REVISED SEPTEMBER 2025

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