Datasheet

LMD18245
SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com
ONE-PHASE-ON FULL STEP DRIVE (WAVE DRIVE)
To make the motor take full steps, windings A and B can be energized in the sequence
A→B→A*→B*→A→ …,
where A represents winding A energized with current in one direction and A* represents winding A energized
with current in the opposite direction. The motor takes one full step each time one winding is de-energized and
the other is energized. To make the motor step in the opposite direction, the order of the above sequence must
be reversed. Figure 15 shows the winding currents and digital control signals for a wave drive application of the
typical application circuit.
TWO-PHASE-ON FULL STEP DRIVE
To make the motor take full steps, windings A and B can also be energized in the sequence
AB→A*B→A*B*→AB*→AB→ …,
and because both windings are energized at all times, this sequence produces more torque than that produced
with wave drive. The motor takes one full step at each change of direction of either winding current. Figure 16
shows the winding currents and digital control signals for this application of the typical application circuit, and
Figure 17 shows, for a single phase, the winding current and voltage at the output of the associated current
sense amplifier.
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