TLE5011_11 Datasheet, PDF (8/45 Pages) Infineon Technologies AG – GMR Angle Sensor

TLE5011
Functional Description
2
Functional Description
2.1
General
The GMR angle sensor is implemented in vertical integration. This means that the GMR active areas are
integrated above the logic portion of the TLE5011 device. GMR elements change their resistance depending on
the direction of the magnetic field.
Four individual GMR elements are connected to one Wheatstone sensor bridge. These GMR elements sense
either of two components of the applied magnetic field:
• X component, V_X (cosine)
• Y component, V_Y (sine)
The advantage of a full-bridge structure is that the amplitude of the GMR signal is doubled.
GMR Resistors
S ^0°
V_X
V_Y
N
ADCX+ ADCX-
GND ADCY+ ADCY-
VDDG
90°
Figure 1 Sensitive Bridges of the GMR Angle Sensor
Note: In Figure 1, the arrows in the resistor symbols denote the direction of the reference layer, which is used for
the further explanation (Figure 2).
The output signal of each bridge is only unambiguous over 180° between two maxima. Therefore two bridges are
orientated orthogonally to each other to measure the 360° angle range.
Using the ARCTAN function, the true 360° angle value can be calculated that is represented by the relation of the
cosine (here X) and sine (here Y) signals.
Because only the relative values influence the result, the absolute size of the two signals is of minor importance.
Therefore, most influences on the amplitudes are compensated.
Final Data Sheet
8
V2.0, 2011-03