AN4158 Datasheet, PDF (8/34 Pages) STMicroelectronics – Peak current control with automatic decay adjustment

Stepper motor basics
AN4158
Figure 3. Magnetic field directions in full step and half step driving modes
Phase A
4a ¹ 1a
4
N
3a
3
2
S
2a
Rotor
Stator phases
Phase B
AM15105v1
Mixing the above mentioned two full step driving modes, half step driving is obtained. In half
step driving the stator magnetic field is rotated by 45° at a time (i.e.: half of the full step
rotation) and the resulting rotor movement is half of that obtained using full step driving.
Table 3 summarizes the driving sequences for the different driving modes.
Full step 1ph on
(wave driving)
1
2
3
4
Table 3. Driving sequences
Full step 2ph on
(normal driving)
Half step
Phase A
current
1
Positive
1
2
Positive
3
Zero
2
4
Negative
5
Negative
3
6
Negative
7
Zero
4
8
Positive
Phase B
current
Zero
Positive
Positive
Positive
Zero
Negative
Negative
Negative
Stator magnetic
field position
1
1a
2
2a
3
3a
4
4a
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DocID023635 Rev 2