2-Phase Stepper-Motor Driver
TCA 3727
Overview
Bipolar IC
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
Type
Ordering Code
Package
TCA 3727
Q67000-A8302
P-DIP-20-6
TCA 3727 G
Q67000-A8335
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.
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
TCA 3727 G
Ι 10
1
20
Ι 20
Ι 11
2
19
Ι 21
Phase 1
3
18
Phase 2
OSC
4
17
Inhibit
GND
5
16
GND
GND
6
15
GND
Q11
7
14
Q21
R1
8
13
R2
VS
9
12
VL
Q12
10
11
Q22
Ι10
Ι11
Phase 1
OSC
GND
GND
GND
GND
Q11
R1
+ VS
Q12
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
Ι 20
Ι 21
Phase 2
Inhibit
GND
GND
GND
GND
Q21
R2
+VL
Q22
IEP00898
IEP00696
Figure 1
Pin Configuration (top view)
Semiconductor Group
3
1998-02-01
TCA 3727
Pin Definitions and Functions
Pin No.
Function
1, 2, 19, 20
(1, 2, 23, 24) 1)
Digital control inputs IX0, IX1 for the magnitude of the current of
the particular phase.
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
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 R1 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 IC, with
a stable electrolytic capacitor of at least 10 µF in parallel with a
ceramic capacitor of 220 nF.
12 (14) 1)
Logic supply voltage; either supply with 5 V or connect to + VS
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.
11, 14
(13, 16) 1)
Push-pull outputs Q22, Q21 for phase 2 with integrated free
wheeling diodes.
13 (15) 1)
Resistor R2 for sensing the current in phase 2.
Semiconductor Group
4
1998-02-01
TCA 3727
Pin Definitions and Functions (cont’d)
Pin No.
Function
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.
1)
TCA 3727 G only
Semiconductor Group
5
1998-02-01
TCA 3727
+ VL
12
4
+ VS
9
OSC
7
Ι10
1
Ι11
2
Phase 1
3
Inhibit
17
Phase 1
10
Function
Logic
Phase 1
8
20
Ι 21
19
Phase 2
18
R1
Q21
Phase 2
11
Function
Logic
Phase 2
13
5, 6, 15, 16
GND
Figure 2
Q12
Inhibit
14
Ι 20
Q11
Q22
R2
IEB00697
Block Diagram TCA 3727
Semiconductor Group
6
1998-02-01
TCA 3727
+ VL
14
4
+ VS
11
Oscillator
D11
D12
T11
Ι10
T12
Q11
1
Phase 1
D13
Ι11
2
Phase 1
3
Inhibit
21
Functional
Logic
Phase 1
D14
T13
T14
Q12
R1
Inhibit
D21
Ι20
12
10
D22
T21
T22
16
Q21
24
Phase 2
D23
Ι21
23
Phase 2
22
Functional
Logic
Phase 2
T23
D24
T24
13
15
5-8, 17-19
GND
Figure 3
9
Q22
R2
IEB00899
Block Diagram TCA 3727 G
Semiconductor Group
7
1998-02-01
TCA 3727
Absolute Maximum Ratings
TA = – 40 to 125 °C
Parameter
Symbol
Limit Values Unit Remarks
min. max.
VS
VL
Logic supply voltage
IL
Z-current of VL
IQ
Output current
IGND
Ground current
VIxx
Logic inputs
R1 , R2, oscillator input voltage VRX,
VOSC
Tj
Junction temperature
Tj
Tstg
Storage temperature
Supply voltage
Semiconductor Group
0
52
V
–
0
6.5
V
Z-diode
–
50
mA
–
–1
1
A
–
–2
2
A
–
VL + 0.3 V
– 0.3 VL + 0.3 V
–6
IXX ; Phase 1, 2; Inhibit
–
–
–
125
150
°C
°C
–
max. 1,000 h
– 50
125
°C
–
8
1998-02-01
TCA 3727
Operating Range
Parameter
Symbol Limit Values Unit Remarks
min.
max.
5
50
V
–
Logic supply voltage
VS
VL
4.5
6.5
V
without series
resistor
Case temperature
TC
– 40
110
°C
Supply voltage
measured on pin 5
Pdiss = 2 W
Output current
IQ
VIXX
– 1000 1000 mA
–
–5
VL
V
Rth ja
Junction ambient
Rth ja
Junction ambient
2
(soldered on a 35 µm thick 20 cm
PC board copper area)
Rth jc
Junction case
–
–
56
40
K/W P-DIP-20-3
K/W P-DIP-20-3
–
18
K/W measured on pin 5
P-DIP-20-3
Rth ja
Junction ambient
Rth ja
Junction ambient
2
(soldered on a 35 µm thick 20 cm
PC board copper area)
Rth jc
Junction case
–
–
75
50
K/W P-DSO-24-3
K/W P-DSO-24-3
–
15
K/W measured on pin 5
P-DSO-24-3
Logic inputs
IXX ; Phase 1, 2;
Inhibit
Thermal Resistances
Semiconductor Group
9
1998-02-01
TCA 3727
Characteristics
VS = 40 V; VL = 5 V; – 25 °C ≤ Tj ≤ 125 °C
Parameter
Symbol
Limit Values
min.
typ.
max.
Unit Test Condition
Current Consumption
from + VS
from + VS
IS
IS
–
–
0.2
16
0.5
20
mA
mA
Vinh = L
Vinh = H
IQ1/2 = 0, IXX = L
Vinh = L
Vinh = H
IQ1/2 = 0, IXX = L
from + VL
from + VL
IL
IL
–
–
1.7
18
3
25
mA
mA
IOSC
VOSCL
VOSCH
fOSC
–
–
–
18
110
1.3
2.3
25
–
–
–
35
µA
V
V
kHz
COSC = 2.2 nF
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
Threshold
VI
–
–
IIL
IIL
IIH
2.3
(L→H)
–
–
10
V
L-input current
L-input current
H-input current
1.4
(H→L)
– 10
– 100
–
µA
µA
µA
VI = 1.4 V
VI = 0 V
VI = 5 V
Oscillator
Output charging current
Charging threshold
Discharging threshold
Frequency
–
–
–
Phase Current Selection (R1; R2)
Current Limit Threshold
No current
Hold
Setpoint
Accelerate
Logic Inputs
(IX1 ; IX0 ; Phase x)
Semiconductor Group
10
–
–
–
1998-02-01
TCA 3727
Characteristics (cont’d)
VS = 40 V; VL = 5 V; – 25 °C ≤ Tj ≤ 125 °C
Parameter
Symbol
Limit Values
Unit Test Condition
min.
typ.
max.
2
3
4
V
–
1.7
2.3
2.9
V
–
VInhhy
0.3
0.7
1.1
V
–
VLZ
6.5
7.4
8.2
V
IL = 50 mA
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
IQ = 0.5 A;
Standby Cutout (inhibit)
Threshold
VInh
(L→H)
Threshold
VInh
(H→L)
Hysteresis
Internal Z-Diode
Z-voltage
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
–
–
–
–
–
Diode Transistor Source Pair
(D11, T11; D12, T12; D21, T21; D22, T22)
Saturation voltage
VsatuC
–
0.9
1.2
V
Saturation voltage
VsatuD
–
0.3
0.7
V
Saturation voltage
VsatuC
–
1.1
1.4
V
Saturation voltage
VsatuD
–
0.5
1
V
Reverse current
Forward voltage
Forward voltage
Diode leakage current
IRu
VFu
VFu
ISL
–
–
–
–
–
1
1.1
1
300
1.3
1.4
2
µA
V
V
mA
Semiconductor Group
11
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
1998-02-01
TCA 3727
Quiescent Current IS, IL versus
Supply Voltage VS
Quiescent Current IS, IL versus
Junction Temperature Tj
IED01655
40
IED01656
40
mA
mA
Ι S, Ι L
Ι S, Ι L
T j = 25 C
30
V S = 40V
30
Ι XX = L
ΙL
20
Ι XX = H
ΙL
20
ΙL
Ι XX = L
ΙL
10
10
Ι XX = H
ΙS
ΙS
0
0
10
20
30
V
VS
0
50
Output Current IQX versus
Junction Temperature Tj
Ι QX
0
25
50
75 100 C 150
Tj
Operating Condition:
IED01657
800
-25
VL
VInh
COSC
Rsense
=5V
=H
= 2.2 nF
=1Ω
Load: L = 10 mH
R = 2.4 Ω
fphase = 50 Hz
mode: fullstep
mA
600
400
200
0
-25
0
25
50
Semiconductor Group
75 100 C 150
Tj
12
1998-02-01
TCA 3727
Output Saturation Voltages Vsat
versus Output Current IQ
Forward Current IF of Free-Wheeling
Diodes versus Forward Voltages VF
ΙF
IED01167
1.0
A
V Fl
V Fu
0.8
T j = 25 C
0.6
0.4
0.2
0
0
0.5
1.0
V
1.5
VF
Typical Power Dissipation Ptot versus
Output Current IQ (Non Stepping)
Permissible Power Dissipation Ptot
versus Case Temperature TC
IED01660
12
Measured
at pin 5.
W
Ptot
10
P-DSO-24
8
6
P-DIP-20
4
2
0
-25
Semiconductor Group
13
0
25 50 75 100 125 C 175
Tc
1998-02-01
TCA 3727
Input Characteristics of Ixx, Phase X,
Inhibit
Input Current of Inhibit versus
JunctionTemperature Tj
IED01661
0.8
mA
Ι IXX 0.6
V L = 5V
0.4
0.2
0
0.2
0.4
0.6
0.8
-6
-5
-2
3.9
2
V
6
V IXX
Oscillator Frequency fOSC versus
Junction Temperature Tj
IED01663
30
V S = 40V
V L = 5V
COSZ = 2.2nF
kHz
f OSC
25
20
15
-25 0
25 50 75 100 125 C 150
Tj
Semiconductor Group
14
1998-02-01
TCA 3727
100 µF
220 nF
Ι ΙL
Ι ΙH
1
Ι10
2
Ι11
3
17
VΙ L
VΙ H
ΙS
12
9
VL
VS
VS
Phase 1
Inhibit
Ι 20
19
Ι 21
Q21
Q22
13
Ι OSC VOSC
8
R2
1Ω
VSense
2.2 nF
VSatu
- VFu
7
ΙQ
- Ι Fu
10
Q12
TCA 3727
Phase 2
OSC
4
100 µF
220 nF
Q11
20
18
ΙL
-ΙR
Ι Ru
VSatl
14
11
- VFl
GND
5, 6
15, 16
R1
1Ω
VSense
Ι GND
IES00706
Figure 4
Test Circuit
+5 V
+40 V
100 µF
1
2
3
Micro
Controller
17
20
19
18
Ι10
12
VL
3
VS
Phase 1
Inhibit
Q12
10
TCA 3727
Q21
Ι 20
Ι 21
Phase 2
OSC
4
7
Q11
Ι11
2.2 nF
100 µF
220 nF
220 nF
Q22
13
R2
1Ω
8
R1
1Ω
14
11
M
GND
5, 6
15, 16
IES00707
Figure 5
Application Circuit
Semiconductor Group
15
1998-02-01
TCA 3727
Normal Mode
Accelerate Mode
H
Ι 10
L
t
H
Ι 11
L
t
H
Phase 1
L
t
i acc
i set
Ι Q1
t
i set
i acc
i acc
i set
Ι Q2
t
i set
i acc
Phase 2
Ι 20
Ι 21
t
H
L
t
H
L
t
H
L
IED01666
Figure 6
Full-Step Operation
Semiconductor Group
16
1998-02-01
TCA 3727
Normal Mode
Accelerate Mode
Ι 10
H
L
Ι 11
H
L
t
t
H
L
Phase 1
t
i acc
i set
Ι Q1
t
- i set
- i acc
i acc
i set
Ι Q2
t
- i set
- i acc
Phase 2
H
L
Ι 20
H
L
Ι 21
H
L
t
t
t
IED01667
Figure 7
Half-Step Operation
Semiconductor Group
17
1998-02-01
TCA 3727
Figure 8
Quarter-Step Operation
Semiconductor Group
18
1998-02-01
TCA 3727
H
Ι 10
L
t
H
Ι 11
L
t
H
Phase 1
L
t
i acc
i set
i hold
Ι Q1
t
i hold
i set
i acc
i acc
i set
i hold
Ι Q2
t
i hold
i set
i acc
Phase 2
Ι 20
Ι 21
H
L
t
H
L
t
H
L
t
IED01665
Figure 9
Mini-Step Operation
Semiconductor Group
19
1998-02-01
TCA 3727
V Osc
2.4 V
1.4 V
0
T
t
Ι GND
0
t
V Q12
+ VS
V FU
V sat 1
0
t
V Q11
V satu D
+ VS
V satu C
t
V Q22
+ VS
0
t
V Q21
+ VS
t
Operating conditions:
VS
VL
L phase x
R phase x
V phase x
V Inhibit
V xx
= 40 V
=5V
= 10 mH
= 20 Ω
=H
=H
=L
IED01177
Figure 10 Current Control
Semiconductor Group
20
1998-02-01
TCA 3727
Inhibit
L
V Osc
t
2.3 V
1.3 V
0
Oscillator
High Imped.
Oscillator
High Imped.
t
Phase Changeover
Phase 1
L
Ι GND
t
ΙN
0
t
V Fu
V Q11
Vsatu C
Vsatu D
+V S
High
Impedance
V Fl
V satl
High
Impedance
t
V Q12
+V S
High
Impedance
t
Ι Phase 1
Slow Current Decay
Operating Conditions:
= 40 V
VS
=5V
VΙ
L phase 1 = 10 mH
R phase 1 = 20 Ω
Ι 1X
= L; Ι 1X = H
t
Fast Current Decay
Slow
Current Decay
Fast
Current
Decay by
Inhibit
IED01178
Figure 11 Phase Reversal and Inhibit
Semiconductor Group
21
1998-02-01
TCA 3727
Calculation of Power Dissipation
The total power dissipation Ptot is made up of
(transistor saturation voltage and diode forward voltages),
saturation losses Psat
(quiescent current times supply voltage) and
quiescent losses Pq
(turn-ON / turn-OFF operations).
switching losses Ps
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
V S i D × t DON i D + i R × t ON I N
P S ≅ ------ ---------------------- + ------------------------------ + ----- t DOFF + t OFF
T
2
2
4
IN
Iq
iD
iR
tp
tON
tOFF
tDON
tDOFF
T
d
Vsatl
VsatuC
VsatuD
VFu
VS
VL
IL
= nominal current (mean value)
= quiescent current
= reverse current during turn-on delay
= peak reverse current
= conducting time of chopper transistor
= turn-ON time
= turn-OFF time
= turn-ON delay
= turn-OFFdelay
= cycle duration
= duty cycle tp/T
= saturation voltage of sink transistor (T3, T4)
= saturation voltage of source transistor (T1, T2) during charge cycle
= saturation voltage of source transistor (T1, T2) during discharge cycle
= forward voltage of free-wheeling diode (D1, D2)
= supply voltage
= logic supply voltage
= current from logic supply
Semiconductor Group
22
1998-02-01
TCA 3727
+V S
Tx1
Dx1
Dx2
Tx2
L
Tx3
Dx3
Dx4
Tx4
V sense
R sense
IES01179
Figure 12
Voltage and
Current at
Chopper
Transistor
Turn-ON
Turn-OFF
iR
ΙN
iD
VS + VFu
VS + VFu
Vsatl
t D ON
t D OFF
t ON
tp
t OFF
t
IET01210
Figure 13
Semiconductor Group
23
1998-02-01
TCA 3727
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 Š± 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.
Semiconductor Group
24
1998-02-01
TCA 3727
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.
Semiconductor Group
25
1998-02-01
TCA 3727
Package Outlines
x
8˚ ma
7.6 -0.2 1)
+0.09
0.35 x 45˚
0.23
2.65 max
2.45 -0.2
0.2 -0.1
P-DSO-24-3
(Plastic Dual Small Outline Package)
0.4 +0.8
1.27
0.35 +0.15 2)
0.2 24x
24
1
0.1
10.3 ±0.3
13
15.6 -0.4 1)
12
Index Marking
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
Sorts of Packing
Package outlines for tubes, trays etc. are contained in our
Data Book “Package Information”.
SMD = Surface Mounted Device
Semiconductor Group
26
GPS05144
Dimensions in mm
1998-02-01
TCA 3727
GPD05587
P-DIP-20-6
(Plastic Dual In-line Package)
Sorts of Packing
Package outlines for tubes, trays etc. are contained in our
Data Book “Package Information”.
Semiconductor Group
27
Dimensions in mm
1998-02-01