• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 30 subscribers
  • Views 678 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LDC1000 for wire wound inductors

Akhil Mohan
Prodigy 10 points
Other Parts Discussed in Thread: LDC1000EVM, LDC1612

hi,

In my application, I am using LDC1000 for measuring the inductance of a coil which is wounded on a nonmagnetic electrically conducting hollow cylinder with variable magnetic core.I experimented this with LDC1000EVM, unfortunately am not getting proper result. after some investigation I got to know that the sensor frequency is the trouble for my application. if the sensor frequency is more than 40KHz eddy current effect be predominant than the permeability effect. In LDCEVM  GUI I seen one option sensor frequency which is having value from 2.5KHz to 500KHz, I don't know what exactly it means. please give me some suggestions in which I can use LDC1000 for my application or how can I change the value of Fsensor value in 2.5KHz or below 10Khz.??  is it possible to fix the sensor capacitor value to in micro Farad range??

  • 0
    TI__Genius 14270 points
    Hello Akhil.

    LDCs can effectively drive wire-wound coils. With a very low frequency sensor, it is important to ensure that the sensor Rp is not too low (for the LDC1000, that would be ~798ohms, but it is better to be above 1kohm). The Rp has an inverse relationship to the Inductor Rs - a lower Rs will increase the Rp.

    As for the sensor capacitor, you need to ensure that the sensor capacitor is stable - i.e. no piezoelectric effects, no dC/dV effects, and low soakage. We recommend C0G/NP0 capacitors as they have a very good dielectric, and unfortunately these capacitors are hard to find in the uF range due to physical size limitations.

    If you are measuring the inductance only, consider using the LDC1612, as it can drive a single channel with a lower Rp than the LDC1000, and it can go lower in sensor frequency, and it has improved resolution.

    For the LDC1000, assuming you have an acceptable Rp, you will need adjust the CFB capacitor as described in the datasheet, and adjust the watchdog timer so that it has the correct minimum frequency.

    Regards,

    Chris O