TMC5130A DATASHEET (Rev. 1.14 / 2017-MAY-15)
58
7.6 Freewheeling and Passive Braking
stealthChop provides different options for motor standstill. These options can be enabled by setting
the standstill current IHOLD to zero and choosing the desired option using the FREEWHEEL setting.
The desired option becomes enabled after a time period specified by TPOWERDOWN and
IHOLD_DELAY. The PWM_SCALE regulation becomes frozen once the motor target current is at zero
current in order to ensure a quick startup.
Parameter
Description
General enable for use of stealthChop (register 0
GCONF)
Setting Comment
en_pwm_
mode
Do not use stealthChop
stealthChop enabled
stealthChop also is
1
TPWMTHRS Specifies the upper velocity for operation in 0 …
stealthChop voltage PWM mode. Entry the TSTEP 1048575 disabled if TSTEP falls
reading (time between two microsteps) when
operating at the desired threshold velocity.
below TCOOLTHRS or
THIGH
pwm_
autoscale
Enable automatic current scaling using current 0
Forward controlled mode
Automatic scaling with
current regulator
fPWM=2/1024 fCLK
measurement or use forward controlled velocity
based mode.
1
PWM_FREQ PWM frequency selection. Use the lowest setting 0
giving good results. The frequency measured at
each of the chopper outputs is half of the
1
2
3
fPWM=2/683 fCLK
fPWM=2/512 fCLK
fPWM=2/410 fCLK
effective chopper frequency fPWM
.
PWM_GRAD User defined PWM amplitude (gradient) for 1 … 15
With pwm_autoscale=1
velocity based scaling or regulation loop gradient
0 … 255 With pwm_autoscale=0
when pwm_autoscale=1.
PWM_AMPL User defined PWM amplitude (offset) for velocity 0 … 255
based scaling or amplitude limit for re-entry into
stealthChop mode when pwm_autoscale=1.
pwm_
symmetric
Activate to force a symmetric PWM for each cycle. 0
Normal operation
A symmetric PWM cycle
is enforced
Reduces the number of updates to the PWM cycle.
Special use only.
1
FREEWHEEL Stand still option when motor current setting is 0
Normal operation
Freewheeling
Coil shorted using LS
drivers
Coil shorted using HS
drivers
zero (I_HOLD=0). Only available with stealthChop
enabled. The freewheeling option makes the
motor easy movable, while both coil short options
realize a passive brake. Mode 2 will brake more
intensely than mode 3, because low side drivers
(LS) have lower resistance than high side drivers.
1
2
3
PWM_SCALE Read back of the actual stealthChop voltage PWM 0 … 255 The scaling value
scaling as determined by the current regulation. (read
Can be used to detect motor load and stall when only)
autoscale=1.
becomes frozen when
operating in a different
chopper mode
Driver off
TOFF
TBL
General enable for the motor driver, the actual 0
value does not influence stealthChop
Comparator blank time. This time needs to safely 0
1 … 15
Driver enabled
16 tCLK
24 tCLK
36 tCLK
54 tCLK
cover the switching event and the duration of the
ringing on the sense resistor. Choose a setting of
1 or 2 for typical applications. For higher
capacitive loads, 3 may be required. Lower
settings allow stealthChop to regulate down to
lower coil current values.
1
2
3
IRUN
IHOLD
Run and hold current setting for stealth Chop
operation – only used with pwm_autoscale=1
See chapter on current
setting for details
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TRINAMIC [ TRINAMIC MOTION CONTROL GMBH & CO. KG. ]
