2-Phase Stepper-Motor Driver
TCA 3727
Overview
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
Bipolar IC
P-DIP-20-6
P-DSO-24-3
Type
TCA 3727
TCA 3727 G
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.
Ordering Code
Q67000-A8302
Q67000-A8335
Package
P-DIP-20-6
P-DSO-24-3
Semiconductor Group
1
1998-02-01
TCA 3727
The direction and value of current are programmed for each phase via separate control
inputs. A common oscillator generates the timing for the current control and turn-on with
phase offset of the two output stages. The two output stages in a full-bridge configuration
have integrated, fast free-wheeling diodes and are free of crossover current. The logic is
supplied either separately with 5 V or taken from the motor supply voltage by way of a
series resistor and an integrated Z-diode. The device can be driven directly by a
microprocessor with the possibility of all modes from full step through half step to mini
step.
Semiconductor Group
2
1998-02-01
TCA 3727
TCA 3727
Ι
10
Ι
11
Phase 1
OSC
GND
GND
Q11
Ι
20
Ι
21
Phase 2
Inhibit
GND
GND
Q21
Ι
10
Ι
11
Phase 1
OSC
GND
GND
GND
GND
Q11
R
1
+
V
S
Q12
TCA 3727 G
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
IEP00696
R
1
V
S
Q12
R
2
V
L
Q22
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
IEP00898
Ι
20
Ι
21
Phase 2
Inhibit
GND
GND
GND
GND
Q21
R
2
+
V
L
Q22
Figure 1
Pin Configuration
(top view)
Semiconductor Group
3
1998-02-01
TCA 3727
Pin Definitions and Functions
Pin No.
1, 2, 19, 20
(1, 2, 23, 24)
1)
Function
Digital control inputs
IX0, IX1
for the magnitude of the
current
of
the particular phase.
IX1
H
H
LH
LL
3
IX0
Phase Current Example of
Motor Status
H
L
0
1/3
I
max
2/3
I
max
No current
Hold
Set
Accelerate
typical
I
max
with
R
sense
= 1
Ω
: 750 mA
I
max
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.
Ground;
all pins are connected internally.
5, 6, 15, 16
(5, 6, 7, 8, 17,
18, 19, 20)
1)
4
8 (10)
1)
7, 10 (9, 12)
1)
9 (11)
1)
Oscillator;
works at approx. 25 kHz if this pin is wired to ground
across 2.2 nF.
Resistor
R
1
for sensing the current in phase 1.
Push-pull outputs Q11, Q12
for phase 1 with integrated
free-wheeling diodes.
Supply voltage;
block to ground, as close as possible to the
IC,
with
a stable electrolytic capacitor of at least 10
µF
in parallel with a
ceramic capacitor of 220 nF.
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
IC
with a stable electrolytic
capacitor of 10
µF
in parallel with a ceramic capacitor of 100 nF.
Push-pull outputs Q22, Q21
for phase 2 with integrated free
wheeling diodes.
Resistor
R
2
for sensing the current in phase 2.
12 (14)
1)
11, 14
(13, 16)
1)
13 (15)
1)
Semiconductor Group
4
1998-02-01
TCA 3727
Pin Definitions and Functions
(cont’d)
Pin No.
17 (21)
1)
18 (22)
1)
Function
Inhibit input;
the IC can be put on standby by low potential on this
pin. This reduces the current consumption substantially.
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.
1)
TCA 3727 G only
Semiconductor Group
5
1998-02-01
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