Datasheet

LMD18245
www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013
Top Trace: Phase A Winding Current at 1A/div
Bottom Trace: Phase A Sense Voltage at 5V/div
Horizontal: 1 ms/div
*500 steps/second
Figure 17. Winding Current and Voltage at the Output of the Associated Current Sense Amplifier
HALF STEP DRIVE WITHOUT TORQUE COMPENSATION
To make the motor take half steps, windings A and B can be energized in the sequence
A→AB→B→A*B→A*→
A*B*→B*→AB*→A→ …
The motor takes one half step each time the number of energized windings changes. It is important to note that
although half stepping doubles the step resolution, changing the number of energized windings from two to one
decreases (one to two increases) torque by about 40%, resulting in significant torque ripple and possibly noisy
operation. Figure 18 shows the winding currents and digital control signals for this half step application of the
typical application circuit.
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