TMC2225 DATASHEET (Rev. 1.15 / 2023-FEB-16)
30
5.4.2 PWMCONF – Voltage PWM Mode StealthChop
0X70: PWMCONF – VOLTAGE MODE PWM STEALTHCHOP
Bit Name
Function
Comment
31 PWM_LIM PWM automatic scale
30
amplitude limit when
29
switching on
28
27 PWM_REG Regulation loop
26
gradient
25
24
Limit for PWM_SCALE_AUTO when switching back from
SpreadCycle to StealthChop. This value defines the upper
limit for bits 7 to 4 of the automatic current control
when switching back. It can be set to reduce the current
jerk during mode change back to StealthChop.
It does not limit PWM_GRAD or PWM_GRAD_AUTO offset.
(Default = 12)
User defined maximum PWM amplitude change per half
wave when using pwm_autoscale=1. (1…15):
1: 0.5 increments (slowest regulation)
2: 1 increment (default with OTP2.1=1)
3: 1.5 increments
4: 2 increments
…
8: 4 increments (default with OTP2.1=0)
...
15: 7.5 increments (fastest regulation)
23 -
reserved
set to 0
22 -
reserved
set to 0
21 freewheel1 Allows different
20 freewheel0 standstill modes
19 pwm_
PWM automatic
autograd gradient adaptation
Stand still option when motor current setting is zero
(I_HOLD=0).
%00: Normal operation
%01: Freewheeling
%10: Coil shorted using LS drivers
%11: Coil shorted using HS drivers
0 Fixed value for PWM_GRAD
(PWM_GRAD_AUTO = PWM_GRAD)
1 Automatic tuning (only with pwm_autoscale=1)
PWM_GRAD_AUTO is initialized with PWM_GRAD
and becomes optimized automatically during
motion.
Preconditions
1. PWM_OFS_AUTO has been automatically
initialized. This requires standstill at IRUN for
>130ms to a) detect standstill b) wait > 128
chopper cycles at IRUN and c) regulate
PWM_OFS_AUTO so that
-1 < PWM_SCALE_AUTO < 1
2. Motor running and PWM_SCALE_SUM < 255 and
1.5 * PWM_OFS_AUTO * (IRUN+1)/32
< PWM_SCALE_SUM <
4 * PWM_OFS_AUTO * (IRUN+1)/32.
Time required for tuning PWM_GRAD_AUTO
About 8 fullsteps per change of +/-1.
18 pwm_
PWM automatic
autoscale amplitude scaling
0 User defined feed forward PWM amplitude. The
current settings IRUN and IHOLD are not enforced
by regulation but scale the PWM amplitude, only!
The resulting PWM amplitude (limited to 0…255) is:
PWM_OFS * ((CS_ACTUAL+1) / 32)
+ PWM_GRAD * 256 / TSTEP
1 Enable automatic current control (Reset default)
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