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TIPD205: Current sensing upto 50A with 0.1% linearity requirements

Yuvraj Singh
Prodigy 10 points
Part Number: TIPD205
Other Parts Discussed in Thread: DRV425

Tool/software:

We've been working on measuring current using the DRV425 IC, for which we made a proper setup using a variac (for variable current supply) along with the TIPD205.
We ended up testing our results on both AC and DC current as supply, but we are unable to get the desired linearity rather it's coming out to be too high, so we are requiring help regarding how we can calibrate it in a better way to get better results. 

Below I am attaching the excel sheets with the tabulated results of our readings for reference.
abbreviations:- m factor - multiplication factor
v - voltage
lin - linearity

DRV425 on AC.xlsxDRV425 on DC.xlsx

  • 0
    TI__Mastermind 30450 points

    Hello Yuvraj,

    I would assume your measurement is greater than 0.1% accuracy.  Do you think you need a little more digits in your measurements?  Did you account for noise in your measurements and are you averaging?  Also our typical linearity of the flux-gate is 0.1%  in this system we will have two DRV425 so I would do RSS on that linearity and expect 0.14% linearity.  Also you can assume a typical value represents 1sigma of device.  

    I did not see you removing offset from the measurements.  I have not seen linearity calculated like this before so I need to look at it some more.

    AC will have larger errors and will change as the frequency changes.  So if the frequency is constant then I have more confidence that you can calibrate with gain and offset  of the system.

    Javier