For a robust magnetic design, the following parameters should be used:
- Magnet shape: Cuboid shaped (7 x 5 x 3 mm)
- Magnet material: NdFeB
- Remanence: 1 T
- Sensor: TLE493D-W1B6
- Air gap between sensor and magnet: 4 mm
- Magnetization: Axial
- Lever arm: 1.3 cm
- Swept angle: 0 ... 30 °
- Six positions result in a resolution of 6 ° per position
The parameters above allow linear behavior between the mechanically deflected angle and the calculated spherical angle Theta (Ɵ). The spherical angle is calculated from the sensor’s x, y, and z components (Figure 5).
This allows the angle to be determined unambiguously, which in turn enables an unambiguous determination of the selector position. A detailed description (application note) is available at www.infineon.com/3dmagnetic.
The TLE493D-W1B6 is also equipped with test functions that make possible malfunction detection during operation, allowing the complete sensor signal chain to be assessed at any time. The test delivers a defined value that the microcontroller can compare with the expected value. If the expected value is obtained, the master does not need to initiate further measures. Test times are significantly lower than 1 ms.
A further intelligent feature of the TLE493D-W1B6 is the magnetic field alert. For all three magnetic field directions, a corridor can be determined in milliTeslas for magnetic field strength. The magnetic field is cyclically measured in the set mode and compared with this corridor. If the measured magnetic field value remains within the corridor in all three directions, the sensor suppresses the interrupt signal. If the measured magnetic field value exceeds the upper corridor value or falls below