Semiconductor Group
1
1998-02-01
2-Phase Stepper-Motor Driver
Overview
Bipolar
IC
TCA 3727
Features
2 x 0.75 amp. / 50 V outputs
Integrated driver, control logic and current control
(chopper)
Fast free-wheeling diodes
Max. supply voltage 52 V
Outputs free of crossover current
Offset-phase turn-ON of output stages
Z-diode for logic supply
Low standby-current drain
Full, half, quarter, mini step
P-DIP-20-6
P-DSO-24-3
Description
TCA 3727 is a bipolar, monolithic IC for driving bipolar stepper motors, DC motors and
other inductive loads that operate on constant current. The control logic and power
output stages for two bipolar windings are integrated on a single chip which permits
switched current control of motors with 0.75 A per phase at operating voltages up to
50 V.
Type
Ordering Code
Package
TCA 3727
Q67000-A8302
P-DIP-20-6
TCA 3727 G
Q67000-A8335
P-DSO-24-3
TCA 3727
Semiconductor Group
4
1998-02-01
Pin Definitions and Functions
Pin No.
Function
1, 2, 19, 20
(1, 2, 23, 24)
1)
Digital control inputs
I
X0,
I
X1 for the magnitude of the current of
the particular phase.
3
Input Phase 1; controls the current through phase winding 1. On
H-potential the phase current flows from Q11 to Q12, on L-potential in
the reverse direction.
5, 6, 15, 16
(5, 6, 7, 8, 17,
18, 19, 20)
1)
Ground; all pins are connected internally.
4
Oscillator; works at approx. 25 kHz if this pin is wired to ground
across 2.2 nF.
8 (10)
1)
Resistor
R
1
for sensing the current in phase 1.
7, 10 (9, 12)
1)
Push-pull outputs Q11, Q12 for phase 1 with integrated
free-wheeling diodes.
9 (11)
1)
Supply voltage; block to ground, as close as possible to the
I
C, with
a stable electrolytic capacitor of at least 10
F in parallel with a
ceramic capacitor of 220 nF.
12 (14)
1)
Logic supply voltage; either supply with 5 V or connect to +
V
S
across a series resistor. A Z-diode of approx. 7 V is integrated. In both
cases block to ground directly on the
I
C with a stable electrolytic
capacitor of 10
F in parallel with a ceramic capacitor of 100 nF.
11, 14
(13, 16)
1)
Push-pull outputs Q22, Q21 for phase 2 with integrated free
wheeling diodes.
13 (15)
1)
Resistor
R
2
for sensing the current in phase 2.
I
X1
I
X0 Phase Current Example of
Motor Status
H
H
0
No current
H
L
1/3
I
max
Hold
LH
2/3
I
max
Set
LL
I
max
Accelerate
typical
I
max
with
R
sense
= 1
: 750 mA
TCA 3727
Semiconductor Group
5
1998-02-01
1)
TCA 3727 G only
17 (21)
1)
Inhibit input; the IC can be put on standby by low potential on this
pin. This reduces the current consumption substantially.
18 (22)
1)
Input phase 2; controls the current flow through phase winding 2. On
H-potential the phase current flows from Q21 to Q22, on L potential in
the reverse direction.
Pin Definitions and Functions (cont'd)
Pin No.
Function