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1,075
1,050
1,025
1,000
0,975
0,950
0,925
-50
Figure 5-1 Example thermal behavior of magnetic remanence M(T) and application sensitivity polynomial
S
(T) with reference temperature 48°C.
app
The reference temperature T
TLE4997 that is configured in the EEPROM, applies at this reference temperature.
In case the calibration of the offset and gain for the output charateristic is done after the calibration of the
temperature compensation, the choice of T
configured separately. A choice of T
in the definition of TCAL in
The application sensitivity polynomial S
temperature dependency of the remanence, as stated in
(
) M
⋅
(
) cons
S
T
T
App
J
R
A
M
is the remanence of the permanent magnet as a function of temperature and T
R
the application that relates to the junction temperature T
⋅
(
U I ⋅
T
T
R
=
+
J
A
th
R
is the thermal resistance of the TLE4997 as specified in the data sheet, U is the supply voltage and I is the
th
supply current.
After determining the application sensitivity polynomial S
sensor parameters TL
compensation of the Hall sensing element drift (given by the precalibrated values TL
cancellation of the thermal reduction of the magnet's remanence (given by S
(
) S
≈
S
T
DSPfinal
J
DSPpre
S
(T
) is the integrated temperature polynomial given by the combination of
DSPfinal
J
Equation
(5.2), with the final parameters TL
with the pre-configured parameters TL
After determination of the application sensitivity polynomial coefficients and readout of the pre-configured TL
TQ
, and TT parameters via the programming interface, the optimum TL
pre
derived from
Equation (5.6)
User's Manual
0
is a degree of freedom that can be chosen by the user, such that the gain of the
0
is not relevant. In this case, the gain at a specific temperature is
0
= 48°C is recommended for simplicity (to match the reference temperature
0
Equation
(5.2)).
has to be determined in the application to approximately cancel the
App
≈
tan
t
)
and TQ
for the final sensor configuration have to be adapted to combine the
final
final
(
) S
⋅
(
)
T
T
J
App
J
final
and TQ
pre
and programmed into the TLE4997.
Calibration of TLE4997 Temperature Compensation
50
100
T
(°C)
J
Equation (5.4)
by
Equation
(5.5).
J
from a sensitivity measurement over temperature, the
App
and TQ
. S
(T
) is the integrated temperature polynomial
final
DSPpre
J
.
pre
26
User's Manual
MR(T)
Sapp(T)
MR(T)*Sapp(T)
150
and illustrated in
Figure
is the ambient temperature in
A
and TQ
pre
), as stated in
Equation
App
Equation (5.1)
and TQ
parameters have to be
final
final
TLE4997
5-1.
(5.4)
(5.5)
) and the
pre
(5.6).
(5.6)
and
,
pre
v01_01, 2019-08
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