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Current Sensing

Thread Summary

The user is using the ADE9113 for current sensing in a 400V DC line with low current. The final answer confirms that a shunt can be used for current sensing, and the 400V DC will not be applied directly to the IP or IM pins; only the voltage difference across the shunt is considered. Collecting IM to the isolation side GND is correct.
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Category: Hardware
Product Number: ADE9113

Hi,

I am using ADE9113 for current sensing. In our design for filament control we may apply 400V DC with low current. If I want to sense current in this path, then can I just use shunt for this or any other scaling is required? 

If I put shunt in 400V line and connect shunt to IP and IM, then collecting IM to isolation side GND will be correct?

Best Regards,

Amod

  • Hi Amod, 

    The ADE9112/ADE9113 can be used for DC current sense. The AGND(and GNDISO) are going to be connected to one side of the shunt. IM and IP are each going to be connected to one side of the shunt through an anti-aliasing filter. IM and IP can be connected however is most convenient for the layout because current direction can be corrected with the I_ADC_INVERT bit. 

    The DC current flow through the shunt is going to produce heat, so consider that when it is sized.

    The ADC channel is going to produce codes to be read out of the SPI port. Refer to the "ADC Transfer Function" section of the datasheet to scale from codes to the voltage seen at the ADC input. That will be the voltage across the shunt, which is typically converted to current by the MCU.

    Regards,

    Jason   

  • Hi Jason,

    Thanks for your reply. Just one query. This DC current sensing is through 400V DC line (Current is low in mA). Does 400V will get applied to IP or IM or only difference is cosidered?

    Best Regards,

    Amod

  • When the shunt is placed on the supply side, there will be ~400V on all pins 1-14. Only differences of mV between all the ADC input pins. We are measuring the very small difference in voltage across the shunt to determine the current. Voltage measurements will be done through a very high impedance voltage divider. 

    Something like this... 

  • Thanks Jason. This is now clear. 

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