Accurate 3D Measurement of Magnetic Fields for Automotive Gear Selector : Page 3 of 6

October 10, 2016 //By Hannes Birk and Sigmund Zaruba, Infineon Technologies
Accurate 3D Measurement of Magnetic Fields for Automotive Gear Selector
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.
separate registers. While the interface fulfills the I 2C fast-mode specification (400 kBit/s), an optimized electrical circuit allows data rates above 1 MBit/s to be supported. The sensor can also be used in an I 2C bus scheme with other devices in accordance with the I 2C protocol guidelines.

During 3D magnetic field detection, the TLE493D-W1B6 offers 12-bit data resolution for every measurement direction. This enables high data resolution of 0.098 mT/bit (least significant bit, LSB), which allows even the smallest movement of the magnet to be measured. Linear measurements of the magnetic field (B) in relation to each of its axes (Bx, By, and Bz) are also possible for the large linear field range (±150 mT). This means an even longer linear magnetic movement (up to 4 cm) can be measured. The large measurement range also enables a simple, robust, flexible magnetic circuit layout.

Flexible Power Modes for Lowest Power Consumption

After each measurement cycle, the sensor transmits a strong interrupt signal to the connected microcontroller, which can then read out the magnetic and temperature values from the registers. The sensor’s interrupt signal can be used to wake up the microcontroller system from its sleep mode. If the entire system is in sleep mode and only activated in the read-out phase, the total power consumption of the system as a whole is reduced dramatically.

The TLE493D-W1B6 can operate in different modes. Individual operating modes vary by their numbers of measurement cycles per second (Figure 3) and the sensor can be set to the desired mode flexibly during operation.

Figure 3: Overview of the eleven different
operating modes that can be selected

In power down mode, all functional blocks are shut down. In this mode, no magnetic measurements are performed and power consumption drops to 7nA.

In “fast” mode, the readout speed is optimized. While the measurement result is read out, the next magnetic field measurement can

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