INA700 datasheet(10/43 Pages) TI

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7.3.3 Versatile Measurement Capability

While the INA700 operates from a 2.7-V to 5.5-V supply, the device can measure voltage and current on rails

as high as 40 V. The current is measured by sensing the voltage drop across a internal shunt resistor positioned

between the IN+ and IN– pins. The input stage of the INA700 is designed such that the input common-mode

voltage can be higher than the device supply voltage, VS. The supported common-mode voltage range of –0.3

V to +40 V at the input pins is designed for both high-side and low-side current measurements. There are no

special considerations for power-supply sequencing because the common-mode input range and device supply

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

vice-versa without damaging the device.

The device also measures the bus supply voltage through the IN– pin and temperature through the integrated

temperature sensor. The differential shunt voltage is measured between the IN+ and IN– pins, while the bus

voltage is measured with respect to device ground. Monitored bus voltages can range from 0 V to 40 V, while

monitored temperatures can range from –40°C to +125°C.

Shunt voltage, bus voltage, and temperature measurements are multiplexed internally to a single ADC as shown

in Figure 7-4.

IN+

IN-

VBUS

MUX digital

Control

Bus Voltage

Shunt Voltage

Temperature

ADC_IN+

ADC_IN-

To ADC Input

Integrated

Shunt Resistor

TEMP

Temperature

Sensor

Figure 7-4. High-Voltage Input Multiplexer

7.3.4 Internal Measurement and Calculation Engine

The current and charge are calculated after temperature and shunt voltage measurements, while the power and

energy are calculated after a bus voltage measurement. Power and energy are calculated based on the previous

current calculation and the latest bus voltage measurement.

The current, voltage, and temperature values are immediate results when the number of averages is set to one

(see Figure 7-5). However, when averaging is used, each ADC measurement is an intermediate result which is

stored in the corresponding averaging registers. Following every ADC sample, the newly-calculated values for

current, voltage, and temperature are appended to their corresponding averaging registers until the set number

of averages is achieved. After all of the samples have been measured, the average current and voltage is

determined, then the power is calculated and the results are loaded to the corresponding output registers where

they can then be read.

The energy and charge values are accumulated for each conversion cycle. Therefore the INA700 averaging

function is not applied to these.

Calculations for power, charge and energy are performed in the background and do not add to the overall

conversion time.

INA700

SBOSAB4 – MAY 2023

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