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DRV401: accuracy in the full range of 100mA~100A

Annie Liu
Genius 10295 points
Part Number: DRV401
Other Parts Discussed in Thread: DRV425

Hi Team,

The customer wants to make a small size current sensor that can measure AC and DC to replace the current transformer. What is the accuracy of DRV401 and DRV425 in the full range of 100mA~100A? Especially can it be 0.5% or 1% at 100mA?

Thanks,

Annie

  • 0
    TI__Mastermind 32340 points

    Hello Annie,

    The accuracy of these devices can meet the accuracy be the challenge is in the magnetic design.  This is where we can limited guidance but the biggest error will come from the magnetic design.  The DRV401 is more likely to function better because it is a closed loop system design. 

    While the DRV425 is a magnetic sensor only and would need to use the Biot–Savart law to measure current.  The DRV425 is more susceptible to external fields due to how it functions. 

    More details can be seen in the DRV425 product folder.
    https://www.ti.com/tool/DRV425-BUSBAR-EVM

    https://www.ti.com/lit/pdf/sloa237

  • 0 in reply to Javier Contreras4
    TI__Genius 10295 points

    Hi Javier,

    May I confirm that the accuracy of the magnetic core can be 0.5% if the design is reasonable? Is there any information on the magnetic core design?

    Thanks,

    Annie

  • 0 in reply to Annie Liu
    TI__Mastermind 32340 points

    Annie,

    This design for the DRV401 would require the design of the fluxgate probe and the magnetic core (compensation core).  The size of the probe matters as it needs to get saturated with the drive currents on the IS1 and IS2 and be in the range specified in the datasheet.  The coupling between the compensation core and the field probe is very important as this is where the feedback loop is closed.  This is not a simple design as you need some magnetic experience and some simulation is recommended.  There is a 2D software that is free named FEMM but for complex designs a 3D simulator would be recommended.  

    With simulations you could find the coupling between the core and the field probe.  The magnetic design will only be guidance but the customer need to own that part of the design as there are many variables that can be changed.

    From other designs I have seen the 0.5% accuracy over the full range and temperature would require calibration due to all the changing factors.