Historically, measurement applications in automotive, industrial, medical and communications applications have relied on an expensive combination of Hall effect sensors and magnets. However, inductive sensing technology can precisely measure linear/angular position, motion, compression, vibration and metal composition.
Inductive sensing is a non-contact, short-range technology that enables low-cost, high-resolution sensing of conductive objects and metals. It can be used in hostile environments because it is immune to dust, dirt, oil and moisture.
LDCs can be used in applications ranging from simple push buttons, knobs, and on/off switches to high-resolution heart rate monitors, turbine flow meters, and high-speed motor/gear controllers.
Given their versatility, LDCs are used in virtually every industry, from automotive to white goods, consumer electronics and mobile devices to computing, industrial, and medical devices. For example, an LDC could be used in the automotive industry to support a digital speedometer or to implement an anti-lock brake solution. Designers in factory automation could implement this type of solution in automated packaging and production systems. The list of potential applications is very long.
How LDCs work
LDCs integrate on chip all of the external circuitry required to measure the resonant frequency and impedance of an LC resonator. This enables them to regulate the oscillation amplitude at a constant level while monitoring the negative resistance required to obtain steady state oscillation and the oscillation frequency, which enables accurate, precise measurements of inductance and eddy current losses of the LC circuit.
LDCs enable low-power, small footprint, and highly flexible inductive sensing solutions. The sensing element can be a wound wire, a PCB coil, a coil printed with conductive ink on a flexible substrate or even a spring. The target can be an existing conductor in the system, or it can be implemented using pressed foil or conductive ink.
This flexibility in the sensor and target design enables ultra-low system cost and offers a wide range of creative design possibilities. In addition, the sensor can be located remotely from the LDC, allowing for selective sensor placement in a system, including those in harsh environments.
Features of the
LDC1000
include:
- Sub-micron precision
- Adjustable sensing range (via coil design)
- Lower system cost
- Remote sensor placement (decoupling the LDC from harsh environments)
- High durability (non-contact operation)
- Immune to non-conductive environmental interference (dirt, dust, water, oil)
- Limitless system design possibilities
- Supply voltage, analog 5V
- Supply voltage, IO 1.8V to 5V
- Inductance (L) resolution: 24-bit, eddy current losses (Rp) resolution: 16-bit
- LC frequency range 5KHz to 5 MHz
- Serial peripheral interface (SPI) interface to microcontroller (MCU)
The LDC1000 is suitable for applications such as:
- Drive-by-wire systems
- Gear-tooth counting / motor control
- Flow meters
- Open/close detection
- Push-button and touch switches
- Knobs
- Notebook computers
- Game controllers
- Multi-function printers
- Medical devices
- Metal composition detection
The LDC1000 is available now. It provides designers with a low-cost, low-power, low- BOM, and low area board real estate solution for sensing conductive and metal objects. Its immunity to harsh environments enables sensing in applications that were previously very expensive or impossible to produce.
TI offers an evaluation module (EVM) for the LDC1000, as well as design software. You can order the EVM , download the software , get the datasheet or order free samples from TI .
The applications for this device are broad, so you are bound to find an application that fits.
Texas Instruments has sponsored promotion of their inductive sensing solutions on ENGINEERING.com. They have no editorial input to this post - all opinions are mine. Randy Boulter