Hall effect: a voltage (Hall voltage) generated across a conductor carrying current in a magnetic field.
With a proper magnet it is possible to make contactless position sensor that are almost wear free, such as linear position sensor
To solve a position application, Melexis provides a wide range of solutions based on Hall effect. Unlike traditional position sensors, sensitive only to the magnetic flux density perpendicular to the surface of the Hall element, the patented Triaxis technology, thanks to the use of an Integrated Magnetic Concentrator (IMC, a ferromagnetic disk integrated in the chip), measures the three magnetic flux densities (Bx, By and Bz), expanding the possibilities to applications with rotary movement (for example MLX90421, in addition to linear) as well as joystick (for example MLX90378)
More freedom in the application is achieved too
The Triaxis solution provides several advantages:
- Mechanical flexibility
- High operating temperature (because of lower temperature dependency)
- Angle computation stability versus:
- Temperature variations
- Magnetic and mechanical tolerances
- Use of smaller magnets
In details the Triaxis technology uses a magnetic concentrator that allows the measurement of magnetic fields parallel to the sensor and around it more than one Hall plate.
In this way the flux density variation of the magnetic field can be measured and stray field immunity of the sensor, that usually shows up as a homogeneous field across the sensor itself, could be increased.
To further improve this aspect in linear application, Melexis offers Dual-Disk solutions (for example MLX90371 and MLX90377): the same sensor contains two IMCs with a predefined pitch (targeted on the specific sensor product).
The useful signal is the difference (magnetic field gradient) between the results of both IMCs, expressed in mT/mm. Doing so it is possible to remove any homogeneous signal, such as stray field, up to 5mT.
Stray field immune rotary application devices are available too (i.e. MLX90371 and MLX90377).
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