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TMCS1123: Designing with TMCS1123

Part Number: TMCS1123
Other Parts Discussed in Thread: TMUX131

Hello Team,

We have designed a circuit using TMCS1123 for sensing the current from the power supply to a DUT.
The current can go upto 2-3A.
We are planning to use the IC TMCS1123 at the high side.
We need calibration as well.
So we have added another circuit as a current source and the current through the current source can be adjusted by adjusting the voltage of the DAC.


The mux/Swicth will be closed only when we need calibration.
Can anyone comment on this?



  • Hello,

    Thank you for using the TI forum. I am from the team that covers the TMCS1123 and can help with questions about that device. I can still give a general look at the other devices, but if you have specific questions for those then we can forward this thread to those teams once we cover all your TMCS1123 questions. 

    In general, I don't see any concerns with the TMCS1123 in this setup, however, it looks like the TMUX131 has an input/output voltage max of 5.5V, and it looks like you plan to use +12V, so that wouldn't work for that device. Also, it looks like the max current for the TMUX131 is 60mA, which may or may not work for your setup. 

    For calibration, were you wondering about calibrating the TMCS1123? Or are you just using the TMCS1123 to calibrate your system?

    Regards,

    Mitch

  • Hello Mitch,
    Thank you for your reply.
    We can select another MUX/Switch that can handle high current and voltage.

    For calibration, were you wondering about calibrating the TMCS1123? Or are you just using the TMCS1123 to calibrate your system?

    The current source (using the opamp and the transistor) is used to calibrate the TMCS1123 device.
    The accuracy of the current source depends on the resolution of the DAC.
    We don't need a high accuracy, that is why we are using a simple current source like this.

    Can you please suggest me whether there is better ways to calibrate a current sensor.
    If the device was based on a shut resistor, we can provide a constant voltage and thus we can calibrate the device.
    But the TMCS1123 is hall based sensor. How can we calibrate a hall based current sensor

  • Hey Sv,

    Ok, I see what you are saying now. As you noted, really the only way to calibrate a Hall based current sensor for gain error is to run a known current. If you don't need high accuracy, maybe the TMCS1123 is accurate enough for you without calibration. But if you do need calibration, then your method looks like it would work.

    Regards,

    Mitch

  • Hello Mitch,

    Thank you for your reply.

    Can you suggest any other current source circuit that can be used here to calibrate the TMSC1123?

  • Hello Sv,

    We don't have an official recommendation for a current source when calibration is desired. Any method you choose to use to generate a reliable source is sufficient. 

    Regards,

    Mitch