Inductive sensing is bringing a revolution in the technical world. Inductive sensing offers capabilities for measuring position, motion and or composition of a conductive or metal target, with a contact-less, magnet-free sensing technology. In addition, inductive sensing can help to detect twist, compression or extension of a spring.

Now, LDC or Inductance-to-Digital converters from Texas Instruments, such as the LDC1614, is helping to utilize springs and coils as inductive sensors that can deliver better reliability, improved performance and increased flexibility when compared with existing sensing solutions. In addition, inductive sensing offers solutions at lower system costs and with lower power consumption.

Users of LDC technology can expect several advantages –

Higher resolution: 24-bit inductance values and 16-bit resonance impedance offers sub-micron resolutions in position sensing.

Better reliability: sensing is contact-less and therefore, immune to non-conductive contaminants such as dust and dirt.

Increased flexibility: The sensor can be located away from the electronics and in areas that do not have space for PCBs.

Low system power: LDC consumes less than 9mW during standard operations and less than 2mW when in standby mode.

Lower system costs: As no magnets are required for both the sensors and the targets, the entire system can be significantly low-cost.

Limitless possibilities: Permits endless possibilities for innovative and creative system design, such as with conductive ink and pressed foil.

Inductive sensing applications can range from simple push buttons, on/off switches and knobs to high-speed motor controllers, turbine flow meters and high-resolution heart rate monitors. The versatility of the LDC1614 allows it to be used in several markets including medical, industrial, computing, mobile devices, consumer electronics, white goods and automotive industries.

LDC1614, from Texas Instruments, is a series of inductance-to-digital converters comprising four devices. They offer two or four matched channels along with 12-bit or 28-bit resolution. Available in a compact 4x4mm package, users can configure these LDCs easily via an I2C interface. These converters offer precise position and motion sensing almost independent of the environment.

Inductive sensing involves low-cost, high-reliability inductors as sensors. Use of LDC converters enables the sensors to be located remotely from the PCB containing the IC. As the LDC1614 can integrate up to four channels, designers can distribute sensors throughout the system, while centralizing the electronics on a few PCBs. Since the channels are well matched, users can perform ratio metric and differential measurements. That allows easy compensation for aging and environmental conditions, such as those caused by mechanical drift, humidity and temperature.

The 28-bit resolution allows detection of submicron level changes in distance measurements. With the LDC converters supporting a frequency range varying from 1KHz to 10MHz, users can employ a large variety of inductors as sensors. As the converters require powering by a 3.3VDC supply, the power consumption is only about 6.9mW during standard operation and about 0.12mW when in shutdown mode.

TI offers its LDC1614 in QFN-16 packages and in the cheaper WSON-12 packages for both the 12-bit and the 28-bit devices. LDCs applications can be extremely wide-ranging and seemingly endless, covering fields as diverse as automotive, medical, consumer electronics, white goods and other industries.