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DRV5032: Hall effect sensor to measure current

Pallav Gandhi
Intellectual 900 points
Part Number: DRV5032
Other Parts Discussed in Thread: MSP430I2040

Hi all,

I would like to sense if current is flowing through wire or not? For the same i was thinking if i can use DRV5032?

When my circuit is on current flowing will be 60mA @ 230V AC. I was thinking if i will place off wire on/next to DRV5032 will it sense the same and give me digital out put for sensing in controller.

My task is just to confirm if circuit is on or not.

Thanks. Regards.

  • 0
    TI__Expert 5705 points

    Hi Pallav,

    To make sure I understand your requirement clearly,  you have a low-frequency sinusoidal current signal that varies between 0 and some value above 60mA and you want to trigger your controller every time the current value exceeds 60mA. Is that correct?

    The main problem with using the DRV5032 for implementing this function is that the magnetic flux density due to a 60mA current will be negligible (only 12uT at 1mm away), compared to the input range of the DRV5032 (BOP_max = 4.8mT). FYI, you can estimate the flux value using an online calculator such as http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magcur.html.

    Anyway, to use the DRV5032, you will have to gain up the magnetic flux using several windings of the primary current as well as possibly using a flux concentrator, and both options will increase the inductance in the 60mA current path, if that is something you care about.

    Alternatively, you could consider a discrete implementation using a shunt resistor, an isolation amplifier such as the AMC1100 and a comparator.

    Best Regards,

    Harsha

  • 0 in reply to Harsha Munikoti
    Intellectual 900 points
    Hi,

    Thats correct.

    And as you explained i want the exact solution, but as for shunt i will have to disturb its circuit. Actually in our case we have to sense it without any intervention in load circuit.(For the same reason we are using hall effect sensor)

    I found one halleffect sensor also but that has AC output overlaped on DC offcet. We i try to measure it with multimeter it's value is stedy but we i try to measure it in our MSP430i2040 kit its value goes on increasing. Could you pleaqse help in this regards also.

    Regards.
  • 0 in reply to Pallav Gandhi
    TI__Expert 5705 points

    Pallav,

    We've been discussing various options for implementing your contactless current measurement and each option seems to be suitable to a different set of mechanical constraints. A few questions:

    - Does your system have a single conductor that will be carrying the >60mA current or is this an RCD (residual current detect) application where you're sensing a fault condition by measuring the difference between the phase and neutral currents (i.e. 2 physical conductors carrying current instead of 1)?

    - Is the conductor carrying the >60mA current a PCB trace or copper cable? What are its dimensions (or wire gauge)? Also, what is the maximum current your are expecting?

    - If you have any pictures to describe your system that would be very helpful

    We can also support a quick conference call if necessary. Please let us know.

    Best Regards,
    Harsha