Though the electronics industry changes quickly, it’s rare to see a new device category emerge. Texas Instruments said its inductance-to-digital converter combines the basic benefits of inductance sensing while adding conversion capabilities, which will help automakers trim costs and improve reliability.
“This is a new data converter category,” said Jon Baldwin, Product Line Manager, Sensor Signal Path, at TI. “The line is focused on two areas, automotive and industrial, because there are a lot of applications.”
The LDC1000 uses coils and springs as inductive sensors to deliver higher resolution, increased reliability, and greater flexibility than existing contactless sensing technologies. It can be used to measure the position, motion, or composition of a metal or conductive target, as well as detect a spring’s compression or extension. Baldwin noted that the sensor/converter can fulfill many automotive requirements including those for powertrains, partly because it’s immune to nonconductive contaminants such as oil, dirt, and dust.
“It’s well suited for harsh environments because the coil or wire can be a meter or two from the silicon,” Baldwin said. “Silicon can be safely tucked away so reliability can be improved.”
The ability to separate targets and sensors can help reduce manufacturing costs. For example, Hall Effect magnets and sensors must be precisely positioned with little distance between them, so tolerances and positioning have little margin for error. Material costs can also be trimmed with the TI device.
“Many Hall Effect magnets are made with rare-earth materials,” Baldwin said. “Some customers don’t like them because of the environmental cost of extraction as well as the financial costs.”
The device consumes less than 8.5 mW while operating, dropping to 1.25 mW in standby mode. In position-sensing applications, it has sub-micron resolution with 16-bit resonance impedance and 24-bit inductance values.
“This can run at up to 78 kilosamples per second, which is good for applications like motor sensing where you need speed,” Baldwin said. “This is sensitive enough that you can measure spring compression in a car seat and tell if a person is breathing.”