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DRV401-Q1: DRV401-Q1

jie qian
Prodigy 245 points
Part Number: DRV401-Q1
Other Parts Discussed in Thread: DRV401, DRV421

i had developed a current sensor A-sample with DRV401, and after the function test ,i found some questions below:

1.the current test range was too small ,it 's about ±150A. but the test range i expected was ±600A,  which factors i can change to expand the test range?

2.the linearity was great at room temperature, it's about ±0.1%，but when it was  exposured at 125℃， the linearity increased to about 1.5%. it was so bad. how to optimize the temperature drift? thanks very much.

  • 0
    TI__Mastermind 31280 points

    Hello Jie Qian,

    I will be glad to help with your questions.

    1.  The current range will be determined by a couple of factors. The number of turns on your compensation coil will let you know how much current is expected.  So you will have 600A/(number of turns).  This will also be limited by your resistance of your coil.  If you have a high resistance on your compensation coil you could limit your range.  This is because the H-Bridge is limited to 4.2Vpp with a 20 Ω load.  It is also limited to 250mA output drive.  In order improve this you could increase your compensation coil wire.  Please keep in mind the R-shunt is also in series with the compensation coil and adds to the H-Bridge driver load.

    2.  The linearity could be due to changes in physical parameters in either your fluxgate sensor or your compensation coil.

    Did you attempt using the DRV421?  If not could you please tell my why you did not consider it?

  • 0 in reply to Javier Contreras4
    Prodigy 245 points
    Hello Javier, Thank you very much for your professional solutions.
    I will increase compensation coil and do some tests,
    and also i will use DRV421 to do some test. i'm a little worried about the accuracy of DRV421.
  • 0 in reply to Javier Contreras4
    Prodigy 245 points
    and another question, do the current range have relations with the turns of probe coils? if the turns of probe coils is 200 or 500 , what factors will be influenced ? thanks !
    Best Regards.
  • 0 in reply to jie qian
    TI__Mastermind 31280 points
    Hello Jie Qian,

    The DRV421 accuracy I assume has to do with the accuracy of the Vref voltage? If so please keep in mind that if you measure the output voltage referenced to the VREF pin this will not be an issue.

    The more turns on the coil on the probe will change your resistance seen by the IS1 and IS2 pins. This will also change the current required to saturate the probe. Please reference the MAGNETIC PROBE (SENSOR) INTERFACE section of the datasheet and let me know if you have more questions.