Semiconductor Group 1 1998-12-16
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 2 1998-12-16
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.
Figure 1 Pin Configuration
(top view)
TCA 3727 TCA 3727 G
IEP00696
21
Phase 2
Inhibit
GND
GND
Q21Q11
GND
GND
OSC
11
10 11
10
Q22
912
813
714
615
516
417
318
219
120
12
RR
V
S
Q12
V
L
Ι
Phase 1
Ι
Ι
20
Ι
Q12 Q22
Q21
GND
GND
OSC
Phase 1 Phase 2
11
Ι
R
1
IEP00898
10
Ι
GND
Q11
V
S
++
L
V
2
R
Inhibit
Ι20
Ι21
GND
241 232 223 214 205 196 187 178 169 1510 1411 1312
GND
GND
GND
GND
TCA 3727
Semiconductor Group 3 1998-12-16
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
µ
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
µ
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.
IX1 IX0 Phase Current Example of
Motor Status
H H 0 No current
H L 1/3 Imax Hold
LH 2/3 Imax Set
LL Imax Accelerate
typical Imax with
Rsense = 1 Ω : 750 mA
TCA 3727
Semiconductor Group 4 1998-12-16
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
TCA 3727
Semiconductor Group 5 1998-12-16
Figure 2 Block Diagram TCA 3727
IEB00697
12 9
7
10
8
Q11
Q12
R
1
4
1
2
3
OSC
Function
Logic
+
V
LS
V
+
Ι
GND
Phase 1
Phase 1
Phase 1
5, 6, 15, 16
Phase 2
Phase 2
Phase 2
Logic
Function
Inhibit
18
19
20
17
2
R
Q22
Q21
13
11
14
Inhibit
10
11Ι
20Ι
21Ι
TCA 3727
Semiconductor Group 6 1998-12-16
Figure 3 Block Diagram TCA 3727 G
IEB00899
D14D13
D12D11
T14
T12
T13
T11
14 11
9
12
10
Q11
Q12
R
1
4
1
2
3
Oscillator
Functional
Logic
+
V
LS
V
+
Ι
11
GND
Phase 1
Phase 1
Phase 1
5-8, 17-19
Phase 2
Phase 2
Phase 2
Logic
Functional
Inhibit
22
23
24
21
2
R
Q22
Q21
15
13
16
T21
T23
T22
T24
D21 D22
D23 D24
Inhibit
10
Ι
Ι20
Ι21
TCA 3727
Semiconductor Group 7 1998-12-16
Absolute Maximum Ratings
T
A
= – 40 to 125
°
C
Parameter Symbol Limit Values Unit Remarks
min. max.
Supply voltage
V
S
052 V–
Logic supply voltage
V
L
0 6.5 V Z-diode
Z-current of
V
L
I
L
–50 mA–
Output current
I
Q
– 1 1 A –
Ground current
I
GND
– 2 2 A –
Logic inputs
V
I
xx
– 6
V
L
+ 0.3 V
I
XX
; Phase 1, 2; Inhibit
R1 , R2, oscillator input voltage VRX,
VOSC
– 0.3 VL + 0.3 V –
Junction temperature Tj
Tj
–
–125
150 °C
°C–
max. 10,000 h
Storage temperature Tstg – 50 125 °C–
TCA 3727
Semiconductor Group 8 1998-12-16
Operating Range
Parameter Symbol Limit Values Unit Remarks
min. max.
Supply voltage VS550V–
Logic supply voltage VL4.5 6.5 V without series
resistor
Case temperature TC– 40 110 °C measured on pin 5
Pdiss = 2 W
Output current IQ– 1000 1000 mA –
Logic inputs VIXX – 5 VLVIXX ; Phase 1, 2;
Inhibit
Thermal Resistances
Junction ambient
Junction ambient
(soldered on a 35 µm thick 20 cm2
PC board copper area)
Junction case
Junction ambient
Junction ambient
(soldered on a 35 µm thick 20 cm2
PC board copper area)
Junction case
Rth ja
Rth ja
Rth jc
Rth ja
Rth ja
Rth jc
–
–
–
–
–
–
56
40
18
75
50
15
K/W
K/W
K/W
K/W
K/W
K/W
P-DIP-20-3
P-DIP-20-3
measured on pin 5
P-DIP-20-3
P-DSO-24-3
P-DSO-24-3
measured on pin 5
P-DSO-24-3
TCA 3727
Semiconductor Group 9 1998-12-16
Characteristics
VS = 40 V; VL = 5 V; – 25 °C ≤ Tj ≤ 125 °C
Parameter Symbol Limit Values Unit Test Condition
min. typ. max.
Current Consumption
from + VS
from + VS
from + VL
from + VL
IS
IS
IL
IL
–
–
–
–
0.2
16
1.7
18
0.5
20
3
25
mA
mA
mA
mA
Vinh = L
Vinh = H
IQ1/2 = 0, IXX = L
Vinh = L
Vinh = H
IQ1/2 = 0, IXX = L
Oscillator
Output charging current
Charging threshold
Discharging threshold
Frequency
IOSC
VOSCL
VOSCH
fOSC
–
–
–
18
110
1.3
2.3
25
–
–
–
35
µA
V
V
kHz
–
–
–
COSC = 2.2 nF
Phase Current Selection (R1; R2)
Current Limit Threshold
No current
Hold
Setpoint
Accelerate
Vsense n
Vsense h
Vsense s
Vsense a
–
200
460
740
0
250
540
825
–
300
620
910
mV
mV
mV
mV
IX0 = H; IX1 = H
IX0 = L; IX1 = H
IX0 = H; IX1 = L
IX0 = L; IX1 = L
Logic Inputs
(IX1 ; IX0 ; Phase x)
Threshold
L-input current
L-input current
H-input current
VI
IIL
IIL
IIH
1.4
(H→L)
– 10
– 100
–
–
–
–
–
2.3
(L→H)
–
–
10
V
µA
µA
µA
–
VI = 1.4 V
VI = 0 V
VI = 5 V
TCA 3727
Semiconductor Group 10 1998-12-16
Standby Cutout (inhibit)
Threshold
Threshold
Hysteresis
VInh
(L→H)
VInh
(H→L)
VInhhy
2
1.7
0.3
3
2.3
0.7
4
2.9
1.1
V
V
V
–
–
–
Internal Z-Diode
Z-voltage VLZ 6.5 7.4 8.2 V IL = 50 mA
Power Outputs
Diode Transistor Sink Pair
(D13, T13; D14, T14; D23, T23; D24, T24)
Saturation voltage
Saturation voltage
Reverse current
Forward voltage
Forward voltage
Vsatl
Vsatl
IRl
VFl
VFl
–
–
–
–
–
0.3
0.5
–
0.9
1
0.6
1
300
1.3
1.4
V
V
µA
V
V
IQ = – 0.5 A
IQ = – 0.75 A
VQ = 40 V
IQ = 0.5 A
IQ = 0.75 A
Diode Transistor Source Pair
(D11, T11; D12, T12; D21, T21; D22, T22)
Saturation voltage
Saturation voltage
Saturation voltage
Saturation voltage
Reverse current
Forward voltage
Forward voltage
Diode leakage current
VsatuC
VsatuD
VsatuC
VsatuD
IRu
VFu
VFu
ISL
–
–
–
–
–
–
–
–
0.9
0.3
1.1
0.5
–
1
1.1
1
1.2
0.7
1.4
1
300
1.3
1.4
2
V
V
V
V
µA
V
V
mA
IQ = 0.5 A;
charge
IQ = 0.5 A;
discharge
IQ = 0.75 A;
charge
IQ = 0.75 A;
discharge
VQ = 0 V
IQ = – 0.5 A
IQ = – 0.75 A
IF = – 0.75 A
Characteristics (cont’d)
VS = 40 V; VL = 5 V; – 25 °C ≤ Tj ≤ 125 °C
Parameter Symbol Limit Values Unit Test Condition
min. typ. max.
TCA 3727
Semiconductor Group 11 1998-12-16
Quiescent Current IS, IL versus
Supply Voltage VS
Output Current IQX versus
Junction Temperature Tj
Quiescent Current IS, IL versus
Junction Temperature Tj
Operating Condition:
VL = 5 V
VInh = H
COSC = 2.2 nF
Rsense = 1 Ω
Load: L = 10 mH
R = 2.4 Ω
fphase = 50 Hz
mode: fullstep
0102030V50
0
10
20
30
40
mA
Ι
XX
= H
= L
XX
Ι
j
T
= 25 C
S
Ι
L
Ι
L
Ι
IED01655
V
S
Ι
S
,
L
Ι
-25 0 25 50 75 100 C 150
j
T
QX
Ι
IED01657
0
200
800
400
600
mA
-25 0 25 50 75 100 150C
IED01656
XX
Ι
= H
= L
Ι
XX
= 40V
L
Ι
L
Ι
Ι
S
j
T
0
10
40
20
ΙΙ
S
,
30
L
mA
V
S
TCA 3727
Semiconductor Group 12 1998-12-16
Output Saturation Voltages Vsat
versus Output Current IQ
Typical Power Dissipation Ptot versus
Output Current IQ (Non Stepping)
Forward Current IF of Free-Wheeling
Diodes versus Forward Voltages VF
Permissible Power Dissipation Ptot
versus Case Temperature TC
0
00.5
0.2
0.4
0.6
1.0 V1.5
V
F
Ι
F
0.8
A
T
j
= 25 C
Fl
VV
Fu
0
00.5
0.2
0.4
0.6
1.0 V1.5
V
F
Ι
F
0.8
A
T
j
1.0
= 25 C
Fl
VV
Fu
IED01167
P-DSO-24
P-DIP-20
Measured
at pin 5.
IED01660
0
6
8
W
tot
P
12
100-25 0 5025 75 C 175
T
c
10
4
2
125
TCA 3727
Semiconductor Group 13 1998-12-16
Input Characteristics of Ixx, Phase X,
Inhibit
Oscillator Frequency fOSC versus
Junction Temperature Tj
Input Current of Inhibit versus
JunctionTemperature Tj
V
L
= 5V
-6 -5 -2 3.9 2 6
IED01661
0.8
0.4
0
0.4
mA
IXX
Ι
0.8
V
V
IXX
0.2
0.6
0.6
0.2
15
20
25
30
kHz
-25 0 25 50 75 100 125 C 150
V
S
L
V
OSZ
C
= 40V
= 5V
= 2.2nF
OSC
f
j
T
IED01663
TCA 3727
Semiconductor Group 14 1998-12-16
Figure 4 Test Circuit
Figure 5 Application Circuit
IES00706
1
2
3
17
20
19
18
12 9
7
10
14
11
413 8
GNDOSC 5, 6
15, 16
R
1
1Ω
R
2
Ω1
2.2 nF
Phase 1
Phase 2
Inhibit
V
L
V
S
Q11
Q12
Q21
Q22
TCA 3727
220 nF 100 F
µ
220 nF100 F
µ
Ι
L
Ι
S
Ι
GND
Ι
OSC
V
OSC
Ι
Q
Ι
Fu
Ι
R
Ι
Ru
Satl
-
-
V
Satu
V
Fu
V
S
-
V
Ι
V
Ι
Ι
Ι
Ι
ΙL
H
L
H
Ι
10
11
Ι
Ι
Ι
21
20
V
Fl
-
Sense
V
V
V
Sense
IES00707
1
2
3
17
20
19
18
12 3
7
10
14
11
4138
GNDOSC 5, 6
15, 16
R
1
1Ω
R
2
Ω1
2.2 nF
Micro
Controller
Ι
11
20
21
Phase 1
Phase 2
Inhibit
V
L
V
S
Q11
Q12
Q21
Q22
TCA 3727
M
220 nF 100 F
µ
+40 V+5 V
220 nF100 F
µ
10
Ι
Ι
Ι
TCA 3727
Semiconductor Group 15 1998-12-16
Figure 6 Full-Step Operation
t
IED01666
Accelerate Mode Normal Mode
acc
set
L
H
L
H
L
H
Ι
Phase 1
i
Q1
i
Ι
Ι
10
11
set
i
i
acc
i
set
i
acc
i
Q2
Ι
acc
set
i
Ι
21
20
Ι
H
H
L
L
L
H
Phase 2
t
t
t
t
t
t
t
TCA 3727
Semiconductor Group 16 1998-12-16
Figure 7 Half-Step Operation
t
t
t
t
t
t
IED01667
t
Accelerate Mode Normal Mode
t
21
Ι
20
Phase 2
Ι
L
L
H
H
H
L
Q2
Ι
-
-
-
i
set
acc
i
i
set
acc
i
acc
i
Q1
Ι
-
Phase 1
set
i
set
i
L
acc
i
H
10
Ι
11
Ι
H
H
L
L
TCA 3727
Semiconductor Group 17 1998-12-16
Figure 8 Quarter-Step Operation
TCA 3727
Semiconductor Group 18 1998-12-16
Figure 9 Mini-Step Operation
H
L
H
L
H
L
i
set
i
hold
Ι
10
Ι
11
Phase 1
Ι
Q1
t
IED01665
acc
i
set
i
i
hold
acc
i
i
acc
set
i
set
hold
acc
hold
i
i
i
i
Ι
Q2
L
H
H
L
L
H
Ι
Ι
20
21
Phase 2
t
t
t
t
t
t
t
TCA 3727
Semiconductor Group 19 1998-12-16
Figure 10 Current Control
Osc
V
0
Ι
GND
V
Q12
V
S
+
0
S
+
V
V
+
S
+
V
S
t
t
V
FU
sat 1
V
satu D
V
satu C
V
phase x
phase x
Operating conditions:
V
R
L
S
= 40 V
= 10 mH
= 20
IED01177
0
Ω
2.4 V
1.4 V
0
t
t
V
Q11
V
Q22
V
Q21
t
t
T
V
L
= 5 V
Inhibit
xx
V
V
V
phase x
= H
= L
= H
TCA 3727
Semiconductor Group 20 1998-12-16
Figure 11 Phase Reversal and Inhibit
Inhibit
Oscillator
High Imped. Oscillator
High Imped.
Phase 1 Phase Changeover
High
Impedance
High
Impedance
High
Impe-
dance
Slow Current Decay
Fast Current Decay
IED01178
Ι
GND
V
Osc
2.3 V
1.3 V
0
L
L
Ι
N
0
t
V
Q11 satl
V
Fu
VV
satu C satu D
V
Fl
V
S
V
+
Phase 1
Ι
Fast
Current
Decay by
Inhibit
Slow
Current Decay
Operating Conditions:
V
S
= 40 V
V
= 5 V
Ιphase 1
L
phase 1
R
Ι
1X
= 20
= L;
V
+
S
Q12
V
= 10 mH
Ω
1X
Ι
= H
t
t
t
t
t
t
TCA 3727
Semiconductor Group 21 1998-12-16
Calculation of Power Dissipation
The total power dissipation Ptot is made up of
saturation losses Psat (transistor saturation voltage and diode forward voltages),
quiescent losses Pq(quiescent current times supply voltage) and
switching losses Ps(turn-ON / turn-OFF operations).
The following equations give the power dissipation for chopper operation without phase
reversal. This is the worst case, because full current flows for the entire time and
switching losses occur in addition.
Ptot = 2 × Psat + Pq + 2 × Ps
where Psat ≅ IN { Vsatl × d + VFu (1 – d ) + VsatuC × d + VsatuD (1 – d ) }
Pq = Iq × VS + IL × VL
IN= nominal current (mean value)
Iq= quiescent current
iD= reverse current during turn-on delay
iR= peak reverse current
tp= conducting time of chopper transistor
tON = turn-ON time
tOFF = turn-OFF time
tDON = turn-ON delay
tDOFF = turn-OFFdelay
T= cycle duration
d= duty cycle tp/T
Vsatl = saturation voltage of sink transistor (T3, T4)
VsatuC = saturation voltage of source transistor (T1, T2) during charge cycle
VsatuD = saturation voltage of source transistor (T1, T2) during discharge cycle
VFu = forward voltage of free-wheeling diode (D1, D2)
VS= supply voltage
VL= logic supply voltage
IL= current from logic supply
PSVS
T
------ iDtDON
×2
----------------------iDiR
+tON
×
4
------------------------------IN
2
-----tDOFF tOFF
+++
≅
TCA 3727
Semiconductor Group 22 1998-12-16
Figure 12
Figure 13
Dx3 Dx4
Dx1 Dx2
V
S
+
Tx3
Tx1
Tx4
Tx2
L
V
sense
sense
R
IES01179
IET01210
Voltage and
Current at
Chopper
Transistor
t
D
t
ON OFF
t
OFF
t
p
t
V
satl
V
SFu
V
+
i
D
i
R
Ι
N
Turn-ON Turn-OFF
+
V
FuS
V
t
DON
TCA 3727
Semiconductor Group 23 1998-12-16
Application Hints
The TCA 3727 is intended to drive both phases of a stepper motor. Special care has
been taken to provide high efficiency, robustness and to minimize external components.
Power Supply
The TCA 3727 will work with supply voltages ranging from 5 V to 50 V at pin Vs. As the
circuit operates with chopper regulation of the current, interference generation problems
can arise in some applications. Therefore the power supply should be decoupled by a
0.22 µF ceramic capacitor located near the package. Unstabilized supplies may even
afford higher capacities.
Current Sensing
The current in the windings of the stepper motor is sensed by the voltage drop across R1
and R2. Depending on the selected current internal comparators will turn off the sink
transistor as soon as the voltage drop reaches certain thresholds (typical 0 V, 0.25 V,
0.5 V and 0.75 V); (R1 , R2 = 1 Ω). These thresholds are neither affected by variations of
VL nor by variations of VS.
Due to chopper control fast current rises (up to 10 A/µs) will occure at the sensing
resistors R1 and R2. To prevent malfunction of the current sensing mechanism R1 and R2
should be pure ohmic. The resistors should be wired to GND as directly as possible.
Capacitive loads such as long cables (with high wire to wire capacity) to the motor should
be avoided for the same reason.
Synchronizing Several Choppers
In some applications synchrone chopping of several stepper motor drivers may be
desireable to reduce acoustic interference. This can be done by forcing the oscillator of
the TCA 3727 by a pulse generator overdriving the oscillator loading currents
(approximately ≥± 100 µA). In these applications low level should be between 0 V and 1 V
while high level should be between 2.6 V and VL.
Optimizing Noise Immunity
Unused inputs should always be wired to proper voltage levels in order to obtain highest
possible noise immunity.
To prevent crossconduction of the output stages the TCA 3727 uses a special break
before make timing of the power transistors. This timing circuit can be triggered by short
glitches (some hundred nanoseconds) at the Phase inputs causing the output stage to
become high resistive during some microseconds. This will lead to a fast current decay
during that time. To achieve maximum current accuracy such glitches at the Phase
inputs should be avoided by proper control signals.
TCA 3727
Semiconductor Group 24 1998-12-16
Thermal Shut Down
To protect the circuit against thermal destruction, thermal shut down has been
implemented. To provide a warning in critical applications, the current of the sensing
element is wired to input Inhibit. Before thermal shut down occures Inhibit will start to pull
down by some hundred microamperes. This current can be sensed to build a
temperature prealarm.
TCA 3727
Semiconductor Group 25 1998-12-16
Package Outlines
P-DSO-24-3
(Plastic Dual Small Outline Package)
15.6
-0.4
24 13
112
Index Marking
1)
1.27
2)
0.35
+0.15
0.2 24x
-0.2
2.65 max
0.1
0.2
-0.1
2.45
1)
-0.2
7.6
0.35 x 45˚
8˚ max
0.23
+0.09
10.3
±0.3
0.4
+0.8
1) Does not include plastic or metal protrusions of 0.15 max rer side
2) Does not include dambar protrusion of 0.05 max per side
GPS05144
Sorts of Packing
Package outlines for tubes, trays etc. are contained in our
Data Book “Package Information”. Dimensions in mm
SMD = Surface Mounted Device
TCA 3727
Semiconductor Group 26 1998-12-16
Sorts of Packing
Package outlines for tubes, trays etc. are contained in our
Data Book “Package Information”. Dimensions in mm
P-DIP-20-6
(Plastic Dual In-line Package)
GPD05587
