PBL3717A Datasheet, PDF (8/11 Pages) STMicroelectronics – STEPPER MOTOR DRIVER

PBL3717A
Quarter Step Operation
It is preferable to realize the quarter step operation
at full power otherwise the steps will be of very ir-
regular size.
The extra quarter steps are added to the half steps
sequence by puttingone coil on half current accord-
ing to the sequence. _{__}
AB
→
A
2
B
→
B→
A
2
B→
AB →
A
B
2
→
A
etc.
Motor Selection
As the PBL3717A provides constant current drive,
with a switching operation, care must be takento se-
lect stepper motors with low hysteresis losses to
prevent motor over heat.
Figure 6 : Source Saturation Voltage versus
Output Current (recircuit period)
L -C Filter
To reduce EMI and chopping losses in the motor a
low pass L -C filter can be inserted across the out-
puts of the PBL3717A as shown on the followingpic-
ture.
L
≈
1
10
LM
C
≈
4
⋅
10^−10
L
Figure 7 : Source Saturation Voltage versus
Output Current (conduction period)
Figure 8 : Sink Saturation Voltage versus
Output Current
Figure 9 : Comparator Threshold versus
Junction Temperature
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