February 1999
PBL 3717/2
Stepper Motor
Drive Circuit
Description
PBL 3717/2 is a bipolar monolithic circuit intended to control and drive the current in
one winding of a stepper motor.
The circuit consists of a LS-TTL compatible logic input stage, a current sensor, a
monostable multivibrator and a high power H-bridge output stage with built-in
protection diodes.
Two PBL 3717/2 and a small number of external components form a complete
control and drive unit for LS-TTL or microprocessor-controlled stepper motor
systems.
Key Features
• Half-step and full-step modes.
• Switched mode bipolar constant
current drive.
• Wide range of current control
5 - 1200 mA.
• Wide voltage range 10 - 50 V.
• Designed for unstabilized motor
supply voltage.
• Current levels can be selected in
steps or varied continuously.
• Thermal overload protection.
• Built-in recirculation diodes.
V
CC
Schmitt
Trigger
Time
Delay
V
MM
V
MM
L
Phase
I1
I0
V
R
MA
MB
&
+
–
+
–
+
–
GND
&
&
&
≥
1
≥
1
P
B
1
1
1
37
17
/
16-pin plastic
batwing DIP
Output Stage
28-pin plastic
PLCC package
Monostable
t
off
= 0.69 • R • C
T
T
L
PB
PBL 3717/2
E
3
7
71
Current Sensor
T
Figure 1. Block diagram.
1
2
L
B /2
P 17
37
/2
20-pin SO wide
batwing package
ERICSSON [ ERICSSON ]
