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INA240: TINA Simulation Result

Jammy Su1
Prodigy 100 points
Part Number: INA240

Hi Sir/Madam,

I think the input is sinusoidal waveform to simulate three-phase output current and output of IC is also sinusoidal, just different voltage range.

But simulation result is square waveform, is it correct? Is parameter setting wrong? Thanks.

By the way, simulation model is downloaded from TI website.

  • 0 in reply to Jammy Su1
    TI__Mastermind 18780 points

    Jammy,

    The main reason why your simulation isn't converging, is that you are using a voltage generator in the TINA diagram above, not a current waveform. You also  have the voltage waveform directly over the input terminals of the INA240. So what you're doing effectively is slewing the differential voltage of the iNA240 between 50V and -50V. So at 50V, the device is slamming into the upper rail of the device, and at -50, the device recovers, only to slam into the swing to GND limitation of the device. 

    I would recommend you set your system up like this, where the voltage source is the common mode voltage of your signal, and the current source under the sense resistor dictates the current in the line. This should provide the correct output you were expecting:

  • 0 in reply to Carolus Andrews
    Prodigy 100 points

    Hi Carolus,

    Thanks for your reply. Simulation is successful. But I would like to know the purpose what the terminal of shunt resistor needs a dc voltage source and the output of INA240 needs a pull-low resistor.

    Thank you.

  • 0 in reply to Jammy Su1
    TI__Mastermind 18780 points

    Jammy,

    The DC voltage source I use in the simulation above is used to set the high side common mode of the simulation. You may remove it, and use the current source only, but your common mode would become a loop determined value rather than one you are controlling in the simulation. 

    Regarding the pull down resistor on the output of the device, this is not actually a pull-down, but rather a simple dummy load. You are correct that the output can remain floating here.