Infineon Technologies TLE5012B User Manual Download Page 23

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TLE5012B

Specification

User’s Manual

Rev. 1.2, 2018-02

Figure 4-3 Parameter correction with autocalibration mode 3

The autocalibration mode 1 is the quickest mode to correct the parameters. Mode 2 is the slowest method, but
since the parameters are updated by one digit only, it offers robustness against corrupted maxima - minima pair
(in case of a spike, for example).

Condition for usability of Autocalibration:

The autocalibration algorithm relies on the collection of maximum and minimum values of the raw X- and Y-signals
of the sensing elements, therefore it is suitable for applications where a rotor is continuously turning (full 360°
rotations). Compensation parameters for offset and amplitude synchronicity error are calculated from these
minima and maxima only if the temperature did not change by more than 5 Kelvin during their collection, to avoid
temperature-drift induced errors.
For the sensor to be accurate in autocalibration mode, it has to be assured in the application that the calibration
parameters are updated frequently. Thus, autocalibration should only be used in applications where the magnet
regularly rotates by at least one full turn (internal TLE5012B check of full turn requires maximum 1.5 revolutions)
at a temperature which is constant within 5 Kelvin.

Enabling/Disabling of Autocalibration:

When switching autocalibration on or off, the TLE5012B may erroneously trigger the S_FUSE error bit in the status
register, which indicates a configuration CRC error, which is also displayed permanently in the Safety Word of the
SSC communication.
When autocalibration is ON and has to be disabled: write the correct CRC for autocalibration OFF before disabling
autocalibration. This way the sensor will see a consistent state when the first runtime CRC check is done again
and no CRC error will occur. The correct CRC must be calculated on the microcontroller side.
When autocalibration is OFF and has to be enabled or just restarted: after switching the autocalibration mode ON,
the Status Register should be read via SSC after three t

update

periods and an occurring S_FUSE error should be

ignored.

Changing TLE5012B default Configuration, if Autocalibration is enabled

Changing certain TLE5012B default configurations while autocalibration is enabled could lead to corrupted
autocalibration parameters. Therefore, disable autocalibration prior to change the angle direction (ANG_DIR bit
on MOD_2 register), prediction (PREDICT bit on MOD_2 register) or the angle base (ANG_BASE bits on MOD_3
register). Once these parameters have been changed, enable autocalibration again.
An initialization sequence for the case of changing angle direction is shown in

Table 4-1

. This sequence is also

valid for prediction and for angle base. In case of angle base additonal write after the first write is required in order
to re-configure the new angle base value.

-633

- 646

-651

- 653

-658

- 664

-670

-665

-660

-655

-650

-645