Datasheet

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

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Figure 24: Outline of noisy Hall signals (left) due to electromagnetic interference with PWM switching and noise

cleaned Hall signals (right) by PWM center synced sampling of Hall signal vector (H1 H2 H3)

The best is avoiding spikes on digital Hall signals. Nevertheless, to enable lower cost motors with lower

performance Hall signal shielding, the TMC4671 is equipped with Hall Signal spike suppression and PWM

centered Hall signal vector sampling.

To reduce possible current ripple that might by caused by noisy Hall signals, the sampling of the Hall signal

vector can by programmed for sampling once per PWM period at its center. The PWM centered Hall signal

sampling is programmable by HALL_MODE(4) control bit. Continuous sampling is default. This function is

not available for TMC4671-ES engineering samples.

Figure 25: Hall Signal PWM Center Sampling on PWM_CENTER

The PWM center synchronized needs to be qualiﬁed for high speed applications due to reduction of Hall

signals for PWM frequency. The PWM center might have en inﬂuence on Hall signal interpolation and need

to be qualiﬁed if Hall signal interpolation is enabled.

For additional spike suppression, the TMC4671 is equipped with a digital hall signal blanking, to sup-

port lower performance cabling environments. The blank time for the Hall signals is programmable

(HALL_BLANK) in steps of 10 ns from 0 ns up to 4095 ns. The Hall signal blanking time should be pro-

grammed as long as necessary for safe suppression of spikes of maximum duration. On the other side,

the Hall signal blanking should be programmed as short as possible to avoid disturbance by too strong

ﬁltering that might also disturbe the FOC.

Figure 26: Hall Signal Blanking

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