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INA260: Common-mode input voltage

Hannes Brockmann
Prodigy 90 points
Part Number: INA260
Other Parts Discussed in Thread: INA236, INA232

Hello.

In my application, the power output from a solar panel is to be measured with an INA260.
The problem here is that the common mode voltage limits of the INA260 must be observed.
The solar panel supplies max. 40.4V voltage and 11.4 A current.
The inverter as load operates in the range of 22...48V with max. 12A input current.
This means that only the voltage range above which the solar panel supplies more than 22V is of interest.
The approach to comply with the common mode voltage limit of the INA260 is now to raise the ground potential of the measuring circuit by 5V relative to the negative output of the solar panel.
The power value supplied by the INA260 could then not be used because VBUS is 5V lower than the actual bus voltage,
but as the current and voltage can be called up from, the power output could be calculated from P = (U+5V)*I.


What do you think of this approach with regard to the safety of the INA260 and the result of the calculation?

With best regards

Hannes

  • +1
    TI__Mastermind 29010 points

    Hi Hannes,

    This approach should work, and the calculation of power can be done outside the chip as you proposed. In addition, the I2C lines probably need to be level-shifted.

    Please take a look at INA232 or INA236. Although an external shunt is needed, they are capable of withstanding 48V. The circuit would be simpler and more cost-effective.

    If integrated shunt is preferred and if you want to explore other choices, here is a list. Some are capable of common mode voltage of up to 85V

    Regards, Guang