Using LDC for Inductance measurement

user3942103

Prodigy 20 points

Other Parts Discussed in Thread: LDC1612EVM

Hi,

I'm wondering if there is a way to use the LDC familly not for inductive sensing but for inductance measurement.

I was thinking about to made of an easy fully integrated inductance-meter based on LDC.

Maybe somebody already investigated that ... What do you think about this idea ?

I carried out some tests with LDC1612EVM connected to variable inductance and I'm able to measure inductance variation.

Anyway the system is very sensitive to conductive objects proximity.

Does anybody has an idea to minimize that influence ?

Regards

Tim

over 10 years ago

0 Ben Kasemsadeh over 10 years ago

TI__Genius 13650 points

Hello Tim,

yes, you can use the LDC to for inductance measurement. For best accuracy, trace capacitance and precise capacitance of the sensor capacitor should be known.

You will pick up conductive objects within 1-2 coil diameters distance. To mitigate this effect, you can shield with ferrite sheets: https://e2e.ti.com/blogs_/b/analogwire/archive/2014/10/08/inductive-sensing-how-to-shield-from-metal-interference

Note that there is also a minimum inductance that you can use as a sensor: https://e2e.ti.com/blogs_/b/analogwire/archive/2014/11/21/inductive-sensing-sensor-frequency-constraints

If the inductance that you are trying to measure is less than this minimum inductance, you can use a series fixed inductor: https://e2e.ti.com/blogs_/b/analogwire/archive/2014/06/10/inductive-sensing-how-to-use-a-tiny-2mm-pcb-inductor-as-a-sensor

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Using LDC for Inductance measurement