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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 andother inductive loads that operate on constant current. The control logic and poweroutput stages for two bipolar windings are integrated on a single chip which permitsswitched current control of motors with 0.75 A per phase at operating voltages up to50 V.
Type Ordering Code Package
TCA 3727 Q67000-A8302 P-DIP-20-6
TCA 3727 G Q67000-A8335 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 controlinputs. A common oscillator generates the timing for the current control and turn-on withphase offset of the two output stages. The two output stages in a full-bridge configurationhave integrated, fast free-wheeling diodes and are free of crossover current. The logic issupplied either separately with 5 V or taken from the motor supply voltage by way of aseries resistor and an integrated Z-diode. The device can be driven directly by amicroprocessor with the possibility of all modes from full step through half step to ministep.
Semiconductor Group 2 1998-02-01
TCA 3727
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
9 12
8 13
7 14
6 15
5 16
4 17
3 18
2 19
1 20
1 2RR
V S
Q12
VL
Ι
Phase 1
Ι
Ι
20
Ι
Q12 Q22
Q21
GNDGND
OSCPhase 1 Phase 2
11Ι
R1
IEP00898
10Ι
GND
Q11
VS+ +
LV2R
Inhibit
Ι20Ι21
GND
241232223214205196187178169151014111312
GNDGNDGND
GND
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.
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.
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 withRsense = 1 Ω : 750 mA
Semiconductor Group 4 1998-02-01
TCA 3727
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. OnH-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
Semiconductor Group 5 1998-02-01
TCA 3727
Figure 2 Block Diagram TCA 3727
IEB00697
12 9
7
10
8
Q11
Q12
R1
4
1
2
3
OSC
FunctionLogic
+ VL SV+
Ι
GND
Phase 1
Phase 1
Phase 1
5, 6, 15, 16
Phase 2
Phase 2
Phase 2
LogicFunction
Inhibit
18
19
20
17
2R
Q22
Q21
13
11
14
Inhibit
10
11Ι
20Ι
21Ι
Semiconductor Group 6 1998-02-01
TCA 3727
Figure 3 Block Diagram TCA 3727 G
IEB00899
D14D13
D12D11
T14
T12
T13
T11
14 11
9
12
10
Q11
Q12
R1
4
1
2
3
Oscillator
FunctionalLogic
+VL SV+
Ι
11
GND
Phase 1
Phase 1
Phase 1
5-8, 17-19
Phase 2
Phase 2
Phase 2
LogicFunctional
Inhibit
22
23
24
21
2R
Q22
Q21
15
13
16T21
T23
T22
T24
D21 D22
D23 D24
Inhibit
10
Ι
Ι20
Ι21
Semiconductor Group 7 1998-02-01
TCA 3727
Absolute Maximum Ratings
TA = – 40 to 125 °CParameter Symbol Limit Values Unit Remarks
min. max.
Supply voltage VS 0 52 V –
Logic supply voltage VL 0 6.5 V Z-diode
Z-current of VL IL – 50 mA –
Output current IQ – 1 1 A –
Ground current IGND – 2 2 A –
Logic inputs VIxx – 6 VL + 0.3 V IXX ; Phase 1, 2; Inhibit
R1 , R2, oscillator input voltage VRX, VOSC
– 0.3 VL + 0.3 V –
Junction temperature TjTj
––
125150
°C°C
–max. 1,000 h
Storage temperature Tstg – 50 125 °C –
Semiconductor Group 8 1998-02-01
TCA 3727
Operating Range
Parameter Symbol Limit Values Unit Remarks
min. max.
Supply voltage VS 5 50 V –
Logic supply voltage VL 4.5 6.5 V without series resistor
Case temperature TC – 40 110 °C measured on pin 5Pdiss = 2 W
Output current IQ – 1000 1000 mA –
Logic inputs VIXX – 5 VL V IXX ; Phase 1, 2;Inhibit
Thermal Resistances
Junction ambientJunction ambient (soldered on a 35 µm thick 20 cm2
PC board copper area)Junction case
Junction ambientJunction ambient(soldered on a 35 µm thick 20 cm2 PC board copper area)Junction case
Rth jaRth ja
Rth jc
Rth jaRth ja
Rth jc
––
–
––
–
5640
18
7550
15
K/WK/W
K/W
K/WK/W
K/W
P-DIP-20-3P-DIP-20-3
measured on pin 5P-DIP-20-3
P-DSO-24-3P-DSO-24-3
measured on pin 5P-DSO-24-3
Semiconductor Group 9 1998-02-01
TCA 3727
CharacteristicsVS = 40 V; VL = 5 V; – 25 °C ≤ Tj ≤ 125 °CParameter Symbol Limit Values Unit Test Condition
min. typ. max.
Current Consumption
from + VSfrom + VS
from + VLfrom + VL
ISIS
ILIL
––
––
0.216
1.718
0.520
325
mAmA
mAmA
Vinh = LVinh = HIQ1/2 = 0, IXX = LVinh = LVinh = HIQ1/2 = 0, IXX = L
Oscillator
Output charging currentCharging thresholdDischarging thresholdFrequency
IOSCVOSCLVOSCHfOSC
–––18
1101.32.325
–––35
µAVVkHz
–––COSC = 2.2 nF
Phase Current Selection (R1; R2)Current Limit Threshold
No currentHoldSetpointAccelerate
Vsense nVsense hVsense sVsense a
–200460740
0250540825
–300620910
mVmVmVmV
IX0 = H; IX1 = HIX0 = L; IX1 = HIX0 = H; IX1 = LIX0 = L; IX1 = L
Logic Inputs(IX1 ; IX0 ; Phase x)
Threshold
L-input currentL-input currentH-input current
VI
IILIILIIH
1.4(H→L)– 10– 100–
–
–––
2.3(L→H)––10
V
µAµAµA
–
VI = 1.4 VVI = 0 VVI = 5 V
Semiconductor Group 10 1998-02-01
TCA 3727
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 voltageSaturation voltageReverse currentForward voltageForward voltage
VsatlVsatlIRlVFlVFl
–––––
0.30.5–0.91
0.613001.31.4
VVµAVV
IQ = – 0.5 AIQ = – 0.75 AVQ = 40 VIQ = 0.5 AIQ = 0.75 A
Diode Transistor Source Pair(D11, T11; D12, T12; D21, T21; D22, T22)
Saturation voltage
Saturation voltage
Saturation voltage
Saturation voltage
Reverse currentForward voltageForward voltageDiode leakage current
VsatuC
VsatuD
VsatuC
VsatuD
IRu
VFuVFuISL
–
–
–
–
––––
0.9
0.3
1.1
0.5
–11.11
1.2
0.7
1.4
1
3001.31.42
V
V
V
V
µAVVmA
IQ = 0.5 A;chargeIQ = 0.5 A;dischargeIQ = 0.75 A;chargeIQ = 0.75 A;dischargeVQ = 0 VIQ = – 0.5 AIQ = – 0.75 AIF = – 0.75 A
Characteristics (cont’d)VS = 40 V; VL = 5 V; – 25 °C ≤ Tj ≤ 125 °CParameter Symbol Limit Values Unit Test Condition
min. typ. max.
Semiconductor Group 11 1998-02-01
TCA 3727
Quiescent Current IS, IL versusSupply Voltage VS
Output Current IQX versusJunction Temperature Tj
Quiescent Current IS, IL versusJunction Temperature Tj
Operating Condition:
VL = 5 VVInh = HCOSC = 2.2 nFRsense = 1 ΩLoad: L = 10 mH
R = 2.4 Ωfphase = 50 Hzmode: fullstep
0 10 20 30 V 500
10
20
30
40
mA
Ι XX = H
= LXXΙ
jT = 25 C
SΙ
LΙ
LΙ
IED01655
VS
Ι S , LΙ
-25 0 25 50 75 100 C 150
jT
QXΙ
IED01657
0
200
800
400
600
mA
-25 0 25 50 75 100 150C
IED01656
XXΙ = H
= LΙ XX
= 40V
LΙ
LΙΙ S
jT
0
10
40
20
ΙΙ S ,
30
L
mA
VS
Semiconductor Group 12 1998-02-01
TCA 3727
Output Saturation Voltages Vsatversus Output Current IQ
Typical Power Dissipation Ptot versusOutput Current IQ (Non Stepping)
Forward Current IF of Free-WheelingDiodes versus Forward Voltages VF
Permissible Power Dissipation Ptotversus Case Temperature TC
00
0.5
0.2
0.4
0.6
1.0 V 1.5
V F
Ι F
0.8
A
T j
1.0
= 25 C
FlV V Fu
IED01167
P-DSO-24
P-DIP-20
Measuredat pin 5.
IED01660
0
6
8
WtotP
12
100-25 0 5025 75 C 175T c
10
4
2
125
Semiconductor Group 13 1998-02-01
TCA 3727
Input Characteristics of Ixx, Phase X, Inhibit
Oscillator Frequency fOSC versusJunction 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
IXXΙ
0.8
VVIXX
0.2
0.6
0.6
0.2
15
20
25
30
kHz
-25 0 25 50 75 100 125 C 150
V SLVOSZC
= 40V= 5V= 2.2nFOSCf
jT
IED01663
Semiconductor Group 14 1998-02-01
TCA 3727
Figure 4 Test Circuit
Figure 5 Application Circuit
IES00706
1
2
3
17
20
19
18
12 9
7
10
14
11
4 13 8GNDOSC
5, 615, 16
R 11 Ω
R 2Ω12.2 nF
Phase 1
Phase 2
Inhibit
VL VS
Q11
Q12
Q21
Q22
TCA 3727
220 nF 100 Fµ220 nF100 Fµ Ι L Ι S
Ι GND
Ι OSC VOSC
Ι Q
Ι Fu
Ι R
Ι Ru
Satl
-
-
VSatu
VFu
VS
-
VΙVΙ
Ι Ι
Ι Ι L
H
L
H
Ι
10
11
Ι
Ι
Ι
21
20
VFl-
SenseV
V
VSense
IES00707
1
2
3
17
20
19
18
12 3
7
10
14
11
4 13 8GNDOSC
5, 615, 16R 1
1 ΩR 2
Ω12.2 nF
MicroController
Ι
11
20
21
Phase 1
Phase 2
Inhibit
VL VS
Q11
Q12
Q21
Q22
TCA 3727
M
220 nF 100 Fµ
+40 V+5 V
220 nF100 Fµ
10
Ι
Ι
Ι
Semiconductor Group 15 1998-02-01
TCA 3727
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
seti
i acc
i set
i acc
i
Q2Ι
acc
seti
Ι 21
20Ι H
H
L
L
L
HPhase 2
t
t
t
t
t
t
t
Semiconductor Group 16 1998-02-01
TCA 3727
Figure 7 Half-Step Operation
t
t
t
t
t
t
IED01667
t
Accelerate Mode Normal Mode
t
21Ι
20
Phase 2
ΙL
L
H
H
H
L
Q2Ι
-
-
-
i set
acci
i
set
acc
i
acci
Q1Ι
-
Phase 1
seti
seti
L
acci
H
10
Ι11
ΙH
H
L
L
Semiconductor Group 17 1998-02-01
TCA 3727
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
acci
seti
i hold
acci
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
Semiconductor Group 19 1998-02-01
TCA 3727
Figure 10 Current Control
OscV
0
Ι GND
V Q12V S+
0
S+ V
V+ S
+ V S
t
t
V FUsat 1V
satu DV satu CV
phase x
phase x
Operating conditions:
V
RL
S = 40 V
= 10 mH= 20
IED01177
0
Ω
2.4 V
1.4 V0
t
t
V Q11
V Q22
V Q21
t
t
T
V L = 5 V
Inhibit
xx
VV
V phase x= H= L
= H
Semiconductor Group 20 1998-02-01
TCA 3727
Figure 11 Phase Reversal and Inhibit
Inhibit
OscillatorHigh Imped.
OscillatorHigh Imped.
Phase 1Phase Changeover
HighImpedance
HighImpedance
HighImpe-dance
Slow Current Decay
Fast Current Decay
IED01178
Ι GND
V Osc 2.3 V
1.3 V0
L
LΙ N
0
t
V Q11satlV
FuV Vsatu C satu DV
FlV
SV+
Phase 1Ι
FastCurrent
Decay byInhibitSlow
Current Decay
Operating Conditions:V S = 40 VV = 5 VΙ
phase 1L
phase 1RΙ 1X
= 20= L;
V+ SQ12V
= 10 mHΩ1XΙ = H
t
t
t
t
t
t
Semiconductor Group 21 1998-02-01
TCA 3727
Calculation of Power Dissipation
The total power dissipation Ptot is made up ofsaturation losses Psat (transistor saturation voltage and diode forward voltages),quiescent losses Pq (quiescent current times supply voltage) andswitching losses Ps (turn-ON / turn-OFF operations).
The following equations give the power dissipation for chopper operation without phasereversal. This is the worst case, because full current flows for the entire time andswitching 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 currentiD = reverse current during turn-on delayiR = peak reverse currenttp = conducting time of chopper transistortON = turn-ON timetOFF = turn-OFF timetDON = turn-ON delaytDOFF = turn-OFFdelayT = cycle durationd = duty cycle tp/TVsatl = saturation voltage of sink transistor (T3, T4)VsatuC = saturation voltage of source transistor (T1, T2) during charge cycleVsatuD = saturation voltage of source transistor (T1, T2) during discharge cycleVFu = forward voltage of free-wheeling diode (D1, D2)VS = supply voltageVL = logic supply voltageIL = current from logic supply
PS
VS
T------
iD tDON×2
----------------------iD iR+ tON×
4------------------------------
IN
2-----tDOFF tOFF++ +
≅
Semiconductor Group 22 1998-02-01
TCA 3727
Figure 12
Figure 13
Dx3 Dx4
Dx1 Dx2
V S+
Tx3
Tx1
Tx4
Tx2
L
V sense
senseR
IES01179
IET01210
Voltage andCurrent atChopperTransistor
t D t ON OFFtOFFt
pt
Vsatl
VS FuV+
i D
i RΙ N
Turn-ON Turn-OFF
+VFuSV
tDON
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 hasbeen 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 thecircuit operates with chopper regulation of the current, interference generation problemscan arise in some applications. Therefore the power supply should be decoupled by a0.22 µF ceramic capacitor located near the package. Unstabilized supplies may evenafford higher capacities.
Current Sensing
The current in the windings of the stepper motor is sensed by the voltage drop across R1and R2. Depending on the selected current internal comparators will turn off the sinktransistor 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 ofVL nor by variations of VS.
Due to chopper control fast current rises (up to 10 A/µs) will occure at the sensingresistors R1 and R2. To prevent malfunction of the current sensing mechanism R1 and R2should 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 shouldbe avoided for the same reason.
Synchronizing Several Choppers
In some applications synchrone chopping of several stepper motor drivers may bedesireable to reduce acoustic interference. This can be done by forcing the oscillator ofthe 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 and1 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 highestpossible noise immunity.
To prevent crossconduction of the output stages the TCA 3727 uses a special breakbefore make timing of the power transistors. This timing circuit can be triggered by shortglitches (some hundred nanoseconds) at the Phase inputs causing the output stage tobecome high resistive during some microseconds. This will lead to a fast current decayduring that time. To achieve maximum current accuracy such glitches at the Phaseinputs 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 beenimplemented. To provide a warning in critical applications, the current of the sensingelement is wired to input Inhibit. Before thermal shut down occures Inhibit will start to pulldown by some hundred microamperes. This current can be sensed to build atemperature prealarm.
Semiconductor Group 25 1998-02-01
TCA 3727
Package Outlines
P-DSO-24-3(Plastic Dual Small Outline Package)
15.6-0.4
24 13
1 12
Index Marking
1)
1.272)0.35 +0.15
0.2 24x-0
.2
2.65
max
0.1
0.2
-0.1
2.45
1)-0.27.6
0.35 x 45˚
8˚ m
ax
0.23
+0.0
9
10.3 ±0.3
0.4 +0.8
1) Does not include plastic or metal protrusions of 0.15 max rer side2) Does not include dambar protrusion of 0.05 max per side GPS05144
Sorts of PackingPackage outlines for tubes, trays etc. are contained in our Data Book “Package Information”.
Dimensions in mmSMD = Surface Mounted Device
Semiconductor Group 26 1998-02-01
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