INA233 datasheet(13/48 Pages) TI1

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INA233

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SBOS790 – APRIL 2017

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Feature Description (continued)

7.3.5 Multiple Fault Event Reporting

The INA233 open-drain ALERT pin can report if any of the following errors simultaneously occur:

•

Overcurrent warning

•

Overpower warning

•

Bus overvoltage warning

•

Bus undervoltage warning

•

Communication faults

•

ADC overflow

•

Conversion ready

The warning thresholds for the current, power, and bus voltages are set with the IOUT_OC_WARN_LIMIT,

PIN_OP_WARN_LIMIT, VIN_UV_WARN_LIMIT, and VIN_OV_WARN_LIMIT standard PMBus commands.

Various bus communications faults are supported as outlined in the STATUS_CML PMBus command.

The status for the conversion ready and ADC overflow bits can be monitored by the STATUS_MFR_SPECIFIC

command. The conversion ready bit notifies when the device completes the previous conversion and is ready to

begin a new conversion. Conversion ready can be monitored at the ALERT pin along with one of the alert

functions. If an alert function and the conversion ready are both enabled to be monitored at the ALERT pin, then

after the ALERT pin is asserted, the MFR_ALERT_MASK register or the PMBus status registers must be read

following the alert to determine the source of the alert.

If the alert function is not used, the ALERT pin can be left floating without affecting device operation.

7.4 Device Functional Modes

7.4.1 Continuous verses Triggered Operation

The internal ADC has two operating modes, continuous and triggered, that determine how the ADC operates

following shunt voltage and bus voltage conversions. When the device is in normal operating mode, the INA233

continuously converts a shunt voltage reading followed by a bus voltage reading. After the shunt voltage reading,

the current value is calculated. This current value is then used to calculate the power result. These values are

subsequently stored in an accumulator, and the measurement and calculation sequence repeats until the number

of averages set in the MFR_ADC_CONFIG register is reached. Following every sequence, the present set of

values measured and calculated are appended to previously collected values. After all averaging completes, the

final values for the shunt voltage, bus voltage, current, and power are updated in the corresponding registers that

can then be read.

The MFR_ADC_CONFIG command allows for selecting modes that only convert the shunt voltage or the bus

voltage to further allow the monitoring function to be configured to better fit the specific application requirements.

This command also allows the device to be configured in continuous-versus-triggered operation. In triggered

mode, writing any of the triggered convert modes into the MFR_ADC_CONFIG register triggers a single-shot

conversion. This action produces a single set of measurements; thus, to trigger another single-shot conversion,

the MFR_ADC_CONFIG register must be written to a second time, even if the mode does not change.

7.4.2 Device Shutdown

In addition to the two operating modes (continuous and triggered), the internal ADC also has a power-down

mode that reduces the quiescent current and turns off current into the device inputs, reducing the effect of supply

drain when the device is not being used. Full recovery from power-down mode requires 40 µs. The device

registers can be written to and read from when the device is in power-down mode. The device remains in power-

down mode until one of the active modes settings is selected using the MFR_ADC_CONFIG command.

7.4.3 Averaging and Conversion Time Considerations

The INA233 offers programmable conversion times (tCT) for both the shunt voltage and bus voltage

measurements. The conversion times for these measurements can be selected from as fast as 140 µs to as long

as 8.244 ms. The conversion time settings, along with the programmable averaging mode, allow the device to be

configured to optimize the available timing requirements in a given application. For example, if a system requires

that data be read every 5 ms, the device can be configured with the conversion times set to 588 µs for both

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