Datasheet

TMC5160 DATASHEET (Rev. 1.01 / 2017-NOV-29) 20
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Figure 3.6 Ringing of output (blue) and Gate voltages (Yellow, Cyan) with untuned brige
Figure 3.7 Switching event with optimized components (without / after bulk diode conduction)
BRIDGE OPTIMIZATION EXAMPLE
A stepper driver for 6A of motor current has been designed using the MOSFET AOD4126 in the
standard schematic.
The MOSFETs have a low gate capacitance and offer roughly 50ns slope time at the lowest driver
strength setting. At lowest driver strength setting, switching quality is best (Figure 3.6), but still
shows a lot of ringing. Low side gate resistors have been added to slightly increase switching slope
time following high-side bulk diode conduction by increasing the effect of Gate-Drain (Miller) charge.
High side gate resistors have been added for symmetry. Tests showed, that 1nF output capacitors
dramatically reduce ringing of the power bridge following bulk diode conduction (Figure 3.7). Figure
3.8 shows the actual components and values after optimization.