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INA260

SBOS656A – JULY 2016 – REVISED AUGUST 2016

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Copyright © 2016, Texas Instruments Incorporated

Feature Description (continued)

NOTE

Do not apply more than 36 V of actual voltage to the input pins.

There are no special considerations for power-supply sequencing because the common-mode input range and

power-supply voltage are independent of each other; therefore, the bus voltage can be present with the supply

voltage off, and vice-versa.

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

these conversions. When the device is in the normal operating mode (that is, MODE bits of the Configuration

Register (00h) are set to '111'), it continuously converts an internal shunt voltage reading followed by a bus

voltage reading. After the measurement of the internal 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/calculation sequence repeats until the number of averages set in the

Configuration Register (00h) is reached. Following every sequence, the present set of values measured and

calculated are appended to previously collected values. After all of the averaging has been completed, the final

values for bus voltage, current, and power are updated in the corresponding registers that can then be read.

These values remain in the data output registers until they are replaced by the next fully completed conversion

results. Reading the data output registers does not affect a conversion in progress.

The mode control in the Configuration Register (00h) also permits selecting modes to convert only the current or

the bus voltage in order to further allow the user to configure the monitoring function to fit the specific application

requirements.

All current and power calculations are performed in the background and do not contribute to conversion time.

In triggered mode, writing any of the triggered convert modes into the Configuration Register (00h) (that is,

MODE bits of the Configuration Register (00h) are set to ‘001’, ‘010’, or ‘011’) triggers a single-shot conversion.

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

Configuration Register (00h) must be written to a second time, even if the mode does not change.

In addition to the two operating modes (continuous and triggered), the device also has a power-down mode that

reduces the quiescent current and turns off current into the device inputs, reducing the impact of supply drain

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

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

down mode until one of the active modes settings are written into the Configuration Register (00h) .

Although the device can be read at any time, and the data from the last conversion remain available, the

Conversion Ready flag bit (Mask/Enable Register, CVRF bit) is provided to help coordinate one-shot or triggered

conversions. The Conversion Ready flag (CVRF) bit is set after all conversions, averaging, and multiplication

operations are complete.

The Conversion Ready flag (CVRF) bit clears under these conditions:

•

Writing to the Configuration Register (00h), except when configuring the MODE bits for power-down mode; or

•

Reading the Mask/Enable Register (06h)

8.3.3.1 Power Calculation

The Power is calculated following current and bus voltage measurements; see Figure 3. Again, these

calculations are performed in the background and do not add to the overall conversion time. These current and

power values are considered intermediate results (unless the averaging is set to 1) and are stored in an internal

accumulation register, not the corresponding output registers. Following every measured sample, the newly-

calculated values for current and power are appended to this accumulation register until all of the samples have

been measured and averaged based on the number of averages set in the Configuration Register (00h).