Datasheet

TMC4671 Datasheet • IC Version V1.3 | Document Revision V2.00 • 2020-Apr-17

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Figure 23: Hall Sensor Angles

Hall sensors give absolute positions within an electrical period with a resolution of 60

as 16 bit positions

(s16 resp. u16) PHI. With activated interim Hall position interpolation, the user gets high resolution interim

positions when the motor is running at a speed above 60 rpm.

4.6.5 Digital Hall Sensor - Interim Position Interpolation

For lower torque ripple the user can switch on the position interpolation of interim Hall positions. This

function is useful for motors that are compatible with sine wave commutation, but equipped with digital

Hall sensors. When the position interpolation is switched on, it becomes active on speeds above 60 rpm.

For lower speeds it automatically disables itself. This is especially important when the motor has to be at

rest. Hall sensor position interpolation might fail when Hall sensors are not properly placed in the motor.

Please adjust Hall sensor positions for this case.

4.6.6 Digital Hall Sensors - Masking, Filtering, and PWM center sampling

Sometimes digital Hall sensor signals get disturbed by switching events in the power stage. The TMC4671

can automatically mask switching distortions by correct setting of the HALL_MASKING register. When a

switching event occurs, the Hall sensor signals are held for HALL_MASKING value times 10 ns. This way,

Hall sensor distortions are eliminated.

Uncorrelated distortions can be ﬁltered via a digital ﬁlter of conﬁgurable length. If the input signal to the

ﬁlter does not change for HALL_DIG_FILTER_LENGTH times 5 us, the signal can pass the ﬁlter. This ﬁlter

eliminates issues with bouncing Hall signals. naming with Elliot: Masking is better then Blanking

Spikes on Hall signals (Hx that stands for H1, H2, H3) disturb the FOC loop when Hall signals are used for

commutation or for initialization of incremental encoders. Spikes on hall signal lines might occur when

Hall signals are feed on singled ended signal lines in parallel to motor power lines due to electromagnetic

cross talk in a single cable. Long Hall signal lines might cause digital Hall signal cross talk even in separate

fed cables. Cables that provide Hall signals without spikes should be preferred. A good ground for digital

Hall signals is important for clean Hall signals. A good ground shield of the motor might help for clean Hall

signals. In best case, Hall signals are fed within separate shielded signal lines together with diﬀerential line

drivers.

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