TI has first inductance sensor chip

Texas Instruments is proposing inductive sensor technology as a more accurate alternative to magnetic Hall effect sensors and it has introduced its first inductance-to-digital converter (LDC) that uses coils and springs as inductive sensors.

The approach using two forms of position sensing – Eddy current and inductance changes to measure the position, motion, or composition of a metal or conductive target, as well as detect the compression, extension or twist of a spring.

The combination allows for greater accuracy in measuring lateral, axial and rotational motion of the conductor.

According to Jon Baldwin of TI, a position accuracy of 180nm is possible at 0.2mm separation from the target. “A sensing accuracy of 0.1% is achievable at any separation,” said Baldwin.

“It does not have the temperature susceptibility of magnetic sensing,” said Baldwin.

The LDC1000 converter, which is used with a sensing coil which can be printed on a PCB, consumes less than 8.5 mW during standard operation and less than 1.25 mW in standby mode.

There is a cost benefit, because the technique does not require the use of magnets.

A development kit is available, including sample coil designs, created by the Webench online design tool.

Applications for inductive sensing range from simple push buttons, knobs, and on/off switches to high-resolution heart rate monitors, turbine flow meters, and high-speed motor/gear controllers.

It is available in a 16-pin, 4-mm by 5-mm SON package.

An automotive-qualified version will be available the first half of 2014.

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Courtesy of:
Richard Wilson
Electronics Weekly