TMC5161 DATASHEET (Rev. 1.01 / 2018-NOV-20)
17
3.3 MOSFETs and Slope Control
The TMC5161 integrates a discrete MOSFET power stage in order to yield a complete driver. The
MOSFET driver stage allows adaptation of parameters like gate driver current and blank time, in order
to optimally fit the driver with the MOSFETs for the given application. The tiny internal driver stage
operates at 10ns slope with minimum gate driver current setting, which is absolutely sufficient for
minimum power dissipation. Due to the fast slopes, minimum BBM time setting is sufficient.
V12VOUT
Miller plateau
Lx
0V
VVM
Output
slope
Output
slope
BMx
0V
-1.2V
VVM+V12VOUT
VVM
Hx
0V
VCX-VBMx
Miller plateau
Hx-
BMx
0V
tBBM
Effective break-before-make time
tBBM
tBBM
Load pulling BMx down
Figure 3.3 Slopes, Miller plateau and blank time
Load pulling BMx up
The following DRV_CONF parameters allow adapting the driver to the MOSFET bridge:
Parameter
Description
Setting Comment
BBMTIME
Break-before-make time setting to ensure non- 0…8
overlapping switching of high-side and low-side
MOSFETs. BBMTIME allows fine tuning of times in
increments shorter than a clock period.
time[ns]
100ns*32/(32-BBMTIME)
Ensure ~30% headroom
Reset Default: 0
As the TMC5161 switches very fast, a setting of 0
is sufficient.
BBMCLKS
Like BBMTIME, but in multiple of a clock cycle.
The longer setting rules (BBMTIME vs. BBMCLKS).
0 to 2 recommended.
0…15
0: off, use BBMTIME
Reset Default: OTP 4 or 2
As the TMC5161 switches very fast, a setting of 0
is sufficient. However, there is only negligible
difference with settings 2 or 4.
DRV_
STRENGTH
Selection of gate driver current. Higher settings 0…2
give faster slopes. 0 recommended.
Reset Default = 2
0 recommended.
00: ~100ns (reset default)
01: ~200ns
10: ~300ns
11: ~400ns
FILT_ISENSE Filter time constant of sense amplifier to suppress 0…3
ringing and coupling from second coil operation
Hint: Increase setting if motor chopper noise
occurs due to cross-coupling of both coils.
(Reset Default = %00)
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