TLE5009-E2000 Datasheet, PDF (24/32 Pages) Infineon Technologies AG – GMR-Based Angular Sensor

TLE5009
Specification
3.4.4.3 Angle Calculation
To get highly accurate angle values, the following angle calculation must be performed. Figure 13 shows the
implementation within a microcontroller.
Calibrations-
Algorithm
Offset_
corr
Gain_
corr
Angle_
corr
Sensor X
+
* ^X_tmp
Sensor Y
+
Figure 13 Implementation of angle calculation
* ^{Y_tmp Y-Corr}
atan
(Cordic)
Offset Correction (Offset_corr)
After the X and Y values are read out, the room temperature offset value must be subtracted (Equation (22)):
X₁ = X − O_X
(22)
Y₁ = Y − O_Y
Amplitude Normalization (Gain_corr)
The next step is to normalize the X and Y values by using the mean values determined in the calibration.
X₂
=
X₁
A_XM
(23)
Y₂
=
Y₁
A_YM
Non-Orthogonality Correction (Angle_corr)
The influence of the non-orthogonality can be compensated for by using Equation (24), in which only the Y
channel must be corrected.
Y₃
=
Y₂
−
X ₂ *sin(−ϕ )
cos(−ϕ )
(24)
Resulting Angle
After correction of all errors, the resulting angle can be calculated using the arctan function¹⁾.
α
=
arctan(
Y₃
X₂
)
−ϕ_X
(25)
1) Microcontroller library function “arctan2(Y₃,X₂)” works better to resolve 360°
Data Sheet
24
Rev. 1.1, 2012-04