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LDC1612: LDC1612

Filipe Pereira
Prodigy 165 points
Part Number: LDC1612

Hello Kristin,

I made some eletromagnetic simulations using FEMM software to figure out a coil to use with LDC1612. Then, I simulate the coil with and without target and I noted the frequency variantion and Rp variations.

The frequency variation was aprox. 1300 Hz with and withour target, The Rp variation was aprox. 208 Ohms (without target) to 173 (with target). Is it possible the LDC1612 get to measure the this Rp variation?

In think in this case It is necessary set the HIGHER IDRIVE CURRENT.

Thank you very much

  • 0
    TI__Genius 17440 points

    Hi Filipe,

    It's not possible to use the LDC1612 to measure the Rp variation of the sensor. The LDC161x can only peform L-sensing, which we recommend over Rp sensing because of its stronger resistance to temperature changes. However, it's also not possible to use the current sensor with the LDC1612, which requires a minimum Rp of at least 1kohm at all target distances.

    I agree that you may end up needing to use the higher drive current setting, but first you need to improve the Rp value of your sensor. In general, section 1.2 of the LDC Sensor Design app note provides a good explanation of sensor Rp. The equation in that section can guide you in how to modify your L and C values to improve Rp, and the “Spiral_Inductor_Designer” sheet of the LDC Tools Excel calculator is extremely helpful in this process. The excel tool will give warnings if key parameters do not meet datasheet specifications. If you do not have it already, the calculator tool can be downloaded from the Tools & Software section of the LDC1612 product page. Note that the Spiral Inductor Designer is only for PCB coils, which we recommend using over wire-wound coils.

    Please let me know if you have any trouble using the tool.

    Best Regards,

  • 0 in reply to Kristin Jones93
    Prodigy 60 points

    Hi,

    But can the LDC1612 measure an equivalent of the Rp or proximity data? Or the energy loss or a target metal composition change?

    Measuring fs is dependent of Q so of the energy loss just as Rp was, right? (with a difference sensitivity maybe)

    I want to use the LDC1612 to measure a change of metal composition (as the Rp of the former LD1000 did). 

    Thanks in advance,

    David

  • 0 in reply to david chauvin
    TI__Genius 17440 points

    Hi David,

    I have answered your question in this thread: 

    Best Regards,