Accurate 3D Measurement of Magnetic Fields for Automotive Gear Selector

October 05, 2016 // By Hannes Birk and Sigmund Zaruba, Infineon Technologies
The TLE493D-W1B6 magnetic sensor provides accurate three-dimensional (3D) magnetic field measurement, extremely low energy consumption and integrated magnetic field alert functionality. Potential automotive applications for this technology are gear selectors, control elements, top column modules and applications involving linear movements or angle measurement.

Conventional linear Hall sensors, Hall switches and angle sensors are only able to recognize magnetic field components that are perpendicular to the surface of the chip; Giant Magneto-Resistive (GMR) angle sensors measure only the planar-oriented field components. However, the TLE493D-W1B6 sensor is capable of simultaneously determining the x, y, and z coordinates of the magnetic field (Figure 1). Recognition of the magnetic field components of all three axes provides a holistic, three dimensional image of the magnetic field in which the sensor lies. Any movement of the magnet leads to a change in at least one of the magnetic field components, which is recognized by the 3D sensor.


Figure 1: The TLE493D-W1B6 3D magnetic sensor measures
all three field directions of a magnetic field (x, y, and z)

The three dimensional sensor system is made possible by the integration of both vertical and horizontal Hall plates into a single sensor chip. The vertical Hall plates detect the planar-oriented x and y field components, while the horizontal Hall plate detects the vertically oriented field component (z direction).

 

Several innovative, patented concepts were applied in the development of the sensor. Users can define a magnetic field corridor for each magnetic field direction such that if the measured magnetic field lies outside of the corridor, the sensor sends an alert signal to the connected microcontroller. A further development goal was the reduction of power consumption. Thanks to innovative design technologies, such as the energy-saving oscillator, the sensor’s power consumption was reduced to only a few nanoamperes – 7 nA when in “power down” mode, for instance. The result is a silicon component that fits into a small package despite its large functional scope. The TSOP-6 case with six pins is only 2.9 x 1.6 mm in size – making it smaller than any other 3D magnetic sensor on the market.

Because of its low power consumption and its integrated magnetic field alert,

Design category: