The inrush time, tINRUSH, is set using
the 16-bit TINRUSH register. As described earlier, tINRUSH
has a dual purpose:
- tINRUSH is
duration of time for which the stall detection scheme ignores the motor
inrush current. This prevents false detection of stall during start up.
Stall detection is blanked for this duration of time. A detailed description
can be found in the Stall Detection section.
- Additionally,
tINRUSH is also the duration of time for which the soft-start
and stop feature ramps up the speed or voltage from 0 to a value set by
WSET_VSET, or ramps down the speed or voltage from the existing
value to 0.
- When EN_SS is set to
0b, the TINRUSH register bit settings directly
reflect the tINRUSH time. Time tINRUSH can be
set to a value between 5 ms (0000h) and 6.7 s (FFFFh). Default value
is 1 s.
- When EN_SS is set to
1b during motor speed or voltage regulation mode, the target motor
speed or voltage is soft-started and stopped over the duration of
tINRUSH as describe above. In this case,
tINRUSH = TINRUSH x WSET_VSET. As an example, if
WSET_VSET = 10 and intended tINRUSH time is 1 s, then
TINRUSH is to be set to 100 ms.