®
PBL3717A
STEPPER MOTOR DRIVER
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FULL STEP - HALF STEP - QUARTER STEP
OPERATING MODE
BIPOLAR OUTPUT CURRENT UP TO 1 A
FROM 10 V UP TO 46 V MOTOR SUPPLY
VOLTAGE
LOW SATURATION VOLTAGE WITH INTE-
GRATED BOOTSTRAP
BUILT IN FAST PROTECTION DIODES
EXTERNALLY
SELECTABLE
CURRENT
LEVEL
OUTPUT CURRENT LEVEL DIGITALLY OR
ANALOGUE CONTROLLED
THERMAL PROTECTION WITH SOFT INTER-
VENTION
Powerdip 12 + 2 + 2
(Plastic Package)
ORDER CODE :
PBL3717A
DESCRIPTION
The PBL3717A is a monolithic IC which controls and
drives one phase of a bipolar stepper motor with
chopper control of the phase current. Current levels
may be selected in three steps by means of two logic
inputs which select one of three current compara-
tors. When both of these inputs are high the device
is disabled. A separate logic input controls the direc-
tion of current flow.
A monostable, programmed by an external RC net-
work, sets the current decay time.
The power section is a full H-bridge driver with four
internal clamp diodes for current recirculation. An
external connection to the lower emitters is available
for the insertion of a sensing resistor. Two
PBL3717As and few external components form a
complete stepper motor drive subsystem.
The raccomended operating ambient temperature
ranges is from 0 to 70
°C.
The PBL3717A is supplied in a 12 + 2 + 2 lead Pow-
erdip package.
July 2003
PIN CONNECTION
(top view)
1/11
PBL3717A
PIN FUNCTIONS
N°
1
2
3
4
5
6
7
8
Name
UTPUT B
PULSE TIME
SUPPLY VOLTAGE B
GROUND
GROUND
LOGIC SUPPLY
INPUT 1
PHASE
Function
Output Connection (with pin 15). The output stage is a ”H” bridge formed by four
transistors and four diodes suitable for switching applications.
A parallel RC network connected to this pin sets the OFF time of the lower power
transistors. The pulse generator is a monostable triggered by the rising edge of
the output of the comparators (t
off
= 0.69 R
T
C
T
).
Supply Voltage Input for Half Output Stage
See also pin 14.
Ground Connection. With pins 5, 12 and 13 also conducts heat from die to
printed circuit copper.
See pin 4.
Supply Voltage Input for Logic Circuitry
This pin and pin 9 (INPUT 0) are logic inputs which select the outputs of the
three comparators to set the current level. Current also depends on the sensing
resistor and reference voltage. See truth table.
This TTL-compatible logic input sets the direction of current flow through the
load. A high level causes current to flow from OUTPUT A (source) to OUTPUT
B (sink). A schmitt trigger on this input provides good noise immunity and a delay
circuit prevents output stage short circuits during switching.
See INPUT 1 (pin 7) .
Input connected to the three comparators. The voltage across the sense resistor
is feedback to this input through the low pass filter R
C
C
C
. The lower power
transistor are disabled when the sense voltage exceeds the reference voltage of
the selected comparator. When this occurs the current decays for a time set by
R
T
C
T
, t
off
= 0.69 R
T
C
T
.
A voltage applied to this pin sets the reference voltage of the three comparators,
this determining the output current (also thus depending on R
s
and the two inputs
INPUT 0 and INPUT 1).
See pin 4.
See pin 4.
Supply Voltage Input for Half Output Stage. See also pin 13.
See pin 1.
Connection to Lower Emitters of Output Stage for Insertion of Current Sense
Resistor
9
10
INPUT 0
COMPARATOR
INPUT
11
12
13
14
15
16
REFERENCE
GROUND
GROUND
SUPPLY VOLTAGE A
OUTPUT A
SENSE RESISTOR
TRUTH TABLE
Inpu t 0 (pin 9)
H
L
H
L
Input 1 (pin 7)
H
H
L
L
No Current
Low Current
Medium Current
High Current
2/11
PBL3717A
Figure 3 :
Two Phase Bipolar Stepper Motor Driver
Figure 4 :
P.C. Board and Component Layout of the Circuit of fig. 3 (1 : 1 scale)
6/11
