Datasheet
TMC2209 DATASHEET (Rev. 1.03 / 2019-JUN-26) 48
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target current
target current - hysteresis start
target current + hysteresis start
on sd fd sd
target current + hysteresis end
target current - hysteresis end
HDEC
Figure 7.3 SpreadCycle chopper scheme showing coil current during a chopper cycle
These parameters control SpreadCycle mode:
Even at HSTRT=0 and HEND=0, the TMC2209 sets a minimum hysteresis via analog circuitry.
EXAMPLE:
A hysteresis of 4 has been chosen. You might decide to not use hysteresis decrement. In this case
set:
HEND=6 (sets an effective end value of 6-3=3)
HSTRT=0 (sets minimum hysteresis, i.e. 1: 3+1=4)
In order to take advantage of the variable hysteresis, we can set most of the value to the HSTRT, i.e.
4, and the remaining 1 to hysteresis end. The resulting configuration register values are as follows:
HEND=0 (sets an effective end value of -3)
HSTRT=6 (sets an effective start value of hysteresis end +7: 7-3=4)
Parameter
Description
Setting
Comment
TOFF
Sets the slow decay time (off time). This setting also
limits the maximum chopper frequency.
For operation with StealthChop, this parameter is not
used, but it is required to enable the motor. In case
of operation with StealthChop only, any setting is
OK.
Setting this parameter to zero completely disables all
driver transistors and the motor can free-wheel.
0
chopper off
1…15
off time setting
N
CLK
= 24 + 32*TOFF
(1 will work with minimum
blank time of 24 clocks)
TBL
Comparator blank time. This time needs to safely
cover the switching event and the duration of the
ringing on the sense resistor. For most
applications, a setting of 1 or 2 is good. For highly
capacitive loads, a setting of 2 or 3 will be
required.
0
16 t
CLK
1
24 t
CLK
2
32 t
CLK
3
40 t
CLK
HSTRT
Hysteresis start setting. This value is an offset from
the hysteresis end value HEND.
0…7
HSTRT=1…8
This value adds to HEND.
HEND
Hysteresis end setting. Sets the hysteresis end value
after a number of decrements. The sum HSTRT+HEND
must be ≤16. At a current setting of max. 30
(amplitude reduced to 240), the sum is not limited.
0…2
-3…-1: negative HEND
3
0: zero HEND
4…15
1…12: positive HEND