pbl3717as STMicroelectronics, pbl3717as Datasheet - Page 7

• Manufacturer Part Number: pbl3717as
• Description: Stepper Motor Driver
• Manufacturer: STMicroelectronics

Figure 5 : Input and Output Sequences for Half Step and Full Step Operation
APPLICATION INFORMATIONS
Figure 3 shows a typical application in which two
PBL3717A control a two phase bipolar stepper mo-
tor.
Programming
The logic inputs I
the amplitude of the current flowing in the motor
winding according to the truth table of page 2. A high
level on the "PHASE" logic input sets the direction
of that current from output A to output B ; a low level
from output B to output A.
It is recommended that unused inputs are tied to
pin 6 (V
noise problem.
The current levels can be varied continuously by
changing the ref. voltage on pin 11.
Control of the Motor
The stepper motor can rotate in either directions ac-
cording to the sequence of the input signals. It is
possible to obtain a full step, a half step and a quar-
ter step operation.
ss
) or pin 4 (GND) as appropriate to avoid
0
and I
1
set at three different levels
Full Step Operation
Both the windings of the stepper motor are ener-
gized all the time with the same current I
I
quired.
Calling A the condition with winding A energized in
one direction and A in the other direction, the se-
quence for full step rotation is :
For the rotation in the other direction the sequence
must be reserved.
In the full step operation the torque is constant each
step.
Half Step Operation
Power is applied alternately to one winding then
both according to the sequence :
Like full step this can be done at any current level ;
the torque is not constant but it is lower when only
one winding is energized.
A coil is turned off by setting I
0
AB
and I
1
remain fixed at whatever torque value is re-
B
AB
AB
AB
A
AB
AB
0
and I
AB etc.
B
1
AB
both high.
PBL3717A
MA
A etc.
= I
MB
7/11
.