Data Sheet 1 2004-03-01

2-Phase Stepper-Motor Driver

Bipolar-IC

TLE 4728 G

• Error-flag for overload, open load, overtemperature• SMD package P-DSO-24-3

Description

TLE 4728 G is a bipolar, monolithic IC for driving bipolar stepper motors, DC motors andother inductive loads that operate by 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 0.7 A per phase at operating voltages up to 16 V.

The direction and value of current are programmable 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 full-bridge configurationinclude fast integrated free wheeling diodes and are free of crossover current. Thedevice can be driven directly by a microprocessor in several modes by programmingphase direction and current control of each bridge independently.

With the two error outputs the TLE 4728 G signals malfunction of the device. Setting thecontrol inputs high resets the error flag and by reactivating the bridges one by one thelocation of the error can be found.

Type Ordering Code Package

TLE 4728 G Q67006-A9077 P-DSO-24-9

Overview

Features

• 2 × 0.7 amp. full bridge outputs• Integrated driver, control logic and current control

(chopper)• Fast free-wheeling diodes• Max. supply voltage 45 V• Output stages are free of crossover current• Offset-phase turn-ON of output stages• All outputs short-circuit proof

TLE 4728 G

Data Sheet 2 2004-03-01

Figure 1 Pin Configuration (top view)

IEP01211

Q12 12 13 Q2211 14 Error 210 159 16 Q218 17 GND7 186 19

GND 5 20OSC 4 21

Phase 1 3 222 23

Ι 1 24

GNDGNDError 1

1011Ι

GNDGNDGNDQ11R1VS+

2R

Ι 2120Ι

GND

Phase 2

TLE 4728 G

TLE 4728 G

Data Sheet 3 2004-03-01

Pin Definitions and Functions

Pin No. Function

1, 2, 23, 24 Digital control inputs IX0, IX1 for the magnitude of the current of the particular phase.

1) “No current” in both bridges inhibits the circuit and current consumption will sink below 3 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 ... 8, 17 ... 20 Ground; all pins are connected at leadframe internally.

4 Oscillator; works at approx. 25 kHz if this pin is wired to ground across 2.2 nF.

10 Resistor R1 for sensing the current in phase 1.

9, 12 Push-pull outputs Q11, Q12 for phase 1 with integrated free-wheeling diodes.

11 Supply voltage; block to ground, as close as possible to the IC, with a stable electrolytic capacitor of at least 47 µF in parallel with a ceramic capacitor of 100 nF.

14 Error 2 output; signals with “low” the errors: short circuit to ground of one or more outputs or overtemperature.

13, 16 Push-pull outputs Q22, Q21 for phase 2 with integrated free-wheeling diodes.

15 Resistor R2 for sensing the current in phase 2.

Iset = 450 mA with Rsense = 1 Ω

IX1 IX0 Phase Current Example of Motor Status

H H 0 No current1)

H L 0.155 × Iset Hold

L H Iset Normal mode

L L 1.55 × Iset Accelerate

TLE 4728 G

Data Sheet 4 2004-03-01

Figure 2 Block Diagram

21 Error 1 output; signals with “low” the errors: open load or short circuit to + VS of one or more outputs or short circuit of the load or overtemperature.

22 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

TLE 4728 G

Data Sheet 5 2004-03-01

Note: Stresses above those listed here may cause permanent damage to thedevice. Exposure to absolute maximum rating conditions for extendedperiods may affect device reliability.

Absolute Maximum Ratings

Tj = – 40 to 150 °C

Parameter Symbol Limit Values Unit Remarks

min. max.

Supply voltage VS – 0.3 45 V –

Error outputs VErrIErr

– 0.3–

453

VmA

––

Output current IQ – 1 1 A –

Ground current IGND – 2 – A –

Logic inputs VIXX – 15 15 V IXX; Phase 1, 2

Oscillator voltage VOSC – 0.3 6 V –

R1, R2 input voltage VRX – 0.3 5 V –

Junction temperature TjTj

––

125150

°C°C

–Max. 10,000 h

Storage temperature Tstg – 50 125 °C –

Thermal resistancesJunction-ambientJunction-ambient

(soldered on a 35 µm thick20 cm2 PC board copperarea)

Junction-case

Rth jaRth ja

Rth jc

––

–

7550

15

K/WK/W

K/W

––

Measured on pin 5

TLE 4728 G

Data Sheet 6 2004-03-01

Note: In the operating range, the functions given in the circuit description are fulfilled.

For details see next four pages.These parameters are not 100% tested in production, but guaranteed by design.

Operating Range

Parameter Symbol Limit Values Unit Remarks

min. max.

Supply voltage VS 5 16 V –

Case temperature TC – 40 110 °C Measured on pin 5 Pdiss = 2 W

Output current IQ – 800 800 mA –

Logic inputs VIXX – 5 6 V IXX; Phase 1, 2

Error outputs VErrIErr

–0

251

VmA

––

CharacteristicsVS = 6 to 16 V; Tj = – 40 to 130 °C

Parameter Symbol Limit Values Unit Test Condition

min. typ. max.

Current Consumption

From + VSFrom + VS

ISIS

0.820

1.730

2.750

mAmA

IXX = HIXX = L;IQ1, 2 = 0 A

Oscillator

Output charging currentCharging thresholdDischarging thresholdFrequency

IOSCVOSCLVOSCHfOSC

900.81.718

1201.32.324

1351.92.930

µAVVkHz

–––COSC = 2.2 nF

TLE 4728 G

Data Sheet 7 2004-03-01

Phase Current (VS = 9 … 16 V)

Mode “no current”Voltage threshold of current Comparator at Rsense in mode:HoldSetpointAccelerate

IQ

VchVcsVca

– 2

40410630

0

70450700

2

100510800

mA

mVmVmV

IX0 = H; IX1 = H

IX0 = L; IX1 = HIX0 = H; IX1 = LIX0 = L; IX1 = L

Logic Inputs (IX1; IX0; Phase X)

ThresholdHysteresisL-input currentL-input currentH-input current

VIVIHyIILIILIIH

1.2–– 10– 100– 1

1.750– 1– 200

2.2–1– 510

VmVµAµAµA

––VI = 1.2 VVI = 0 VVI = 5 V

Error Outputs

Saturation voltageLeakage current

VErrSatIErrL

50–

200–

50010

mVµA

IErr = 1 mAVErr = 25 V

Thermal Protection

ShutdownPrealarmDelta

TjsdTjpa∆Tj

14012010

15013020

16014030

°C°CK

IQ1, 2 = 0 AVErr = L∆Tj = Tjsd – Tjpa

Characteristics (cont’d)VS = 6 to 16 V; Tj = – 40 to 130 °C

Parameter Symbol Limit Values Unit Test Condition

min. typ. max.

TLE 4728 G

Data Sheet 8 2004-03-01

Power Outputs

Diode Transistor Sink Pair(D13, T13; D14, T14; D23, T23; D24, T24)

Saturation voltageSaturation voltageReverse currentForward voltageForward voltage

VsatIVsatIIRIVFIVFI

0.10.25000.60.7

0.30.510000.91

0.50.815001.21.3

VVµAVV

IQ = – 0.45 AIQ = – 0.7 AVS = VQ = 40 VIQ = 0.45 AIQ = 0.7 A

Diode Transistor Source Pair(T11, D11; T12, D12; T21, D21; T22, D22)

Saturation voltageSaturation voltage

Saturation voltageSaturation voltage

Reverse currentForward voltageForward voltageDiode leakage current

VsatuCVsatuD

VsatuCVsatuD

IRuVFuVFuISL

0.60.1

0.70.2

4000.70.80

10.3

1.20.5

80011.13

1.20.6

1.50.8

12001.31.410

VV

VV

µAVVmA

IQ = 0.45 A; chargeIQ = 0.45 A;dischargeIQ = 0.7 A; chargeIQ = 0.7 A; dischargeVS = 40 V,VQ = 0 VIQ = – 0.45 AIQ = – 0.7 AIF = – 0.7 A

Error Output Timing

Time Phase X to IXXTime IXX to Phase XDelay Phase X to Error 2Delay Phase X to Error 1Delay IXX to Error 2Reset delay after Phase XReset delay after IXX

tPItIPtPEsctPEoltIEsctRPtRI

–––––––

51245153031

15–803060105

µsµsµsµsµsµsµs

–––––––

Characteristics (cont’d)VS = 6 to 16 V; Tj = – 40 to 130 °C

Parameter Symbol Limit Values Unit Test Condition

min. typ. max.

TLE 4728 G

Data Sheet 9 2004-03-01

Diagrams

Timing between IXX and Phase X to prevent setting the error flag

Operating conditions:+ VS = 14 V, Tj = 25 °C, Ierr = 1 mA, load = 3.3 mH, 1 Ω

Figure 3

Figure 4

t PIIET01888

Phase X

XXΙ

a) If tPI < typ. 5 µs, an error “open load” will be set.

t IPIET01889

Phase X

XXΙ

b) If tIP < typ. 12 µs, an error “open load” will be set.

TLE 4728 G

Data Sheet 10 2004-03-01

This time strongly depends on + VS and inductivity of the load, see diagram below.

Time tIP versus Load Inductivity

Propagation Delay of the Error Flag

Operating conditions:+ VS = 14 V, Tj = 25 °C, Ierr = 1 mA, load = 3.3 mH, 1 Ω

Figure 5

t PEsc

Error 2

IET01883

Phase X

a) IXX = L, error condition: short circuit to GND.

typ. tPEsc: 45 µs

TLE 4728 G

Data Sheet 11 2004-03-01

Figure 6

Figure 7

t PEol

Error 1

IET01884

Phase X

b) IXX = L, error condition: open load (equivalent: short circuit to + VS).

typ. tPEol: 15 µs

t IEscIET01885

Error 2

XXΙ

c) Phase X = H or L, const.; error condition: short circuit to GND.

typ. tIEsc: 30 µs

tIEsc is also measured under the condition: begin of short circuit to GND till error flag set.

TLE 4728 G

Data Sheet 12 2004-03-01

Figure 8

Figure 9

t RPIET01886

Error X

Phase x

d) IXX = L, reset of error flag when error condition is not true.

typ. tRP: 3 µs

t RIIET01887

Error X

XXΙ

typ. tRI: 1 µs

e) Phase X = H or L, const.; reset of error flag when error condition is not true.

TLE 4728 G

Data Sheet 13 2004-03-01

Quiescent Current IS versus Supply VoltageVS; bridges not chopping; Tj = 25 °C

Oscillator Frequency fOsc versusJunction Temperature Tj

Quiesc. Current IS versus Junct. Temp. Tj; bridges not chopping, VS = 14 V

Output Current IQX versus JunctionTemperature Tj

IED01827

50

V

mA

V

SΙ

10 15

20

40

60=Ι QX

0.70 A

20

10

30

50

S

0.45 A

0.07 A

-5015

0

20

VC OSC

S

15010050 C

T j

Osc

kHzf

25

30IED01829

= 14 V= 2.2 nF

IED01828

-500

C

mA

T

SΙ

0 50

20

40

60

=Ι QX 0.70 A

150

10

30

50

j

0.50 A

0.07 A

500

-500

0

300

100

400

200R X

VS = 14 V

15010050 C

T j

700

800

600QXΙ

mA

X1 = H, X0 = HΙ

IED01830

Ι

X1 = H, X0 = LΙ Ι

= 1Ω

TLE 4728 G

Data Sheet 14 2004-03-01

Output Saturation Voltages Vsatversus 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 versusCase Temp. TC (measured at pin 5)

V

00

0.2

0.5

1.0

0.60.4 0.8A

Ι Q

satuDVV satl

satuC

satV= 14 VV

1.5

VT j

S= 25 C

2.0IED01831

both phases active

00

0.2

1

2

0.60.4 0.8A

Ι Q

SV = 14 V

totP= 10 mHL

OSC

phase x

phase x

C3TC

WR

= 25 C= 2.2 nF

= 2

4IED01832

Ω

IED01218

00

0.5 1.0 1.5V

0.2

0.4

0.6

0.8

1.0

A

VF

Ι F

= 25 ˚C

VFuVFl

T j

IED01833

-250

W

CT

totP

0 25 75

4

8

12

16

=Tjmax

150 C

120 C

125 175

2

6

10

C

TLE 4728 G

Data Sheet 15 2004-03-01

Input Characteristics of IXX, Phase X

Output Leakage Current

-20

=

-120-4-6 -2

-60

-100

-40

-80

jT

20 64 V

xxV Ι

40 C 25 C

150 C

xxi Ι

A

0

20

40

Phase X

xxΙ

IED01834

µ

0-0.8

-0.4

0

0.4

10 20 30 V

V Q

40

SV = 16 V

mA

0.8

Ι R

1.2

SV = 40 V

IED01835

TLE 4728 G

Data Sheet 16 2004-03-01

Figure 10 Application Circuit

Figure 11 Test Circuit

IES01223

Phase 1

Error 1

Phase 2

1

2

3

21

24

23

22

9

12

16

13

11

4 15 10 5, 6, 7, 8,

TLE 4728G

Q11

Q12

Q21

Q22

R2

1Ω Ω11R

2.2 nF

OSC GND

M

Microcontroller

100 nF

VS

µ100 F

+12 V

11Ι10Ι

21Ι20Ι

14 Error 2

17, 18, 19, 20

StepperMotor

V

V

V Err

2.2 nF

Osc

OSC

OSCΙ

Ι

Ι Ι

Ι

ErrorErr

X

XX, Phase XΙRl

Fu

sense

V C

SLΙ GNDΙ

GND R

1

RsenseΙ

V Fl

Output

V+ S

QΙ

satuV

Ι

V

V satl

IES01836

RuΙ

100 nF100 FSΙ

V S

Ω

µ

TLE 4728 G

TLE 4728 G

Data Sheet 17 2004-03-01

Figure 12 Full Step Operation

t

IED01776

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

TLE 4728 G

Data Sheet 18 2004-03-01

Figure 13 Half Step Operation

t

t

t

t

t

t

IED01777

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

TLE 4728 G

Data Sheet 19 2004-03-01

Figure 14 Current Control in Chop-Mode

V Osc

OscV

OscV

0

0

Ι Rsense 1

Rsense 2Ι

V Q12

0caV

Q11V

V Q22

+V Q21

V S

Q1Ιi acc

i acc

Q2Ιt

t

t

t

t

t

t

V FUsatlV

satu DV satu CV

phase x

phase x

Operating conditions:

V

RL

S = 14 V

Ω= 10 mH= 4

Phase = H

IED01778

0

ΙXX

+V S

+V S

+V S

= L

TLE 4728 G

Data Sheet 20 2004-03-01

Figure 15 Phase Reversal and Inhibit

OscV

Ι Rsense 1

S+ VQ11V

Phase 1Ι

t

t

t

phase 1

phase 1

Operating conditions:

V

RL

S == 14 V= 1 mH= 4

= L for t >

IED01779

t

t

2.3 V

1.3 V

0 V

OscillatorHigh Imped.

Phase change-overHL

Phase 1

0

HighImpedance

setΙ

slow current decay

setΙ-

1T

fast currentdecay

= 2XΙ = H

H for t < T 1

1TΙΙΙ

111110

+

V Q12

V S HighImpedance

t

slow current decay

Ω

TLE 4728 G

Data Sheet 21 2004-03-01

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 × Pswhere

Psat ≅ IN VsatI × d + VFu (1 – d ) + VsatuC × d + VsatuD ( 1 – d )

Pq = Iq × VS

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-OFF delayT = cycle durationd = duty cycle tp / TVsatl = saturation voltage of sink transistor (TX3, TX4)VsatuC = saturation voltage of source transistor (TX1, TX2) during charge cycleVsatuD = saturation voltage of source transistor (TX1, TX2) during discharge cycleVFu = forward voltage of free-wheeling diode (DX1, DX2)VS = supply voltage

PqVS

T------

iD tDON×2

----------------------iD iR+( ) tON×

4----------------------------------

IN

2----- tDOFF tOFF+( )+ +

≅

TLE 4728 G

Data Sheet 22 2004-03-01

Figure 16

Figure 17 Voltage and Current on Chopper Transistor

IET01209

D x 1 D x 2

D x 3 D x 4

T x 2

L

T x 4

T x 3

T x 1

R

+VS

CV

sense

IET01210

Voltage andCurrent atChopperTransistor

t D t ON OFFtOFFt

pt

Vsatl

VS FuV+

i D

i RΙ N

Turn-ON Turn-OFF

+VFuSV

tDON

TLE 4728 G

Data Sheet 23 2004-03-01

Application Hints

The TLE 4728 G 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 TLE 4728 G will work with supply voltages ranging from 5 V to 16 V at pin VS. Surgesexceeding 16 V at VS wont harm the circuit up to 45 V, but whole function is notguaranteed. As soon as the voltage drops below approximately 16 V the TLE 4728 Gworks promptly again.

As the circuit operates with chopper regulation of the current, interference generationproblems can arise in some applications. Therefore the power supply should bedecoupled by a 0.1 µF ceramic capacitor located near the package. Unstabilizedsupplies may even afford higher capacities.

Current Sensing

The current in the windings of the stepper motor is sensed by the voltage drop acrossRsense. Depending on the selected current internal comparators will turn off the sinktransistor as soon as the voltage drop reaches certain thresholds (typical 0 V, 0.07 V,0.45 V and 0.7 V). These thresholds are not affected by variations of VS. Consequentlyunstabilized supplies will not affect the performance of the regulation. For precise currentlevel it must be considered, that internal bounding wire (typ. 60 mΩ) is a part of Rsense.

Due to chopper control fast current rises (up to 10 A/µs) will occur at the sensingresistors. To prevent malfunction of the current sensing mechanism Rsense should bepure ohmic. The resistors should be wired to GND as directly as possible. Capacitiveloads such as long cables (with high wire to wire capacity) to the motor should beavoided for the same reason.

Synchronizing Several Choppers

In some applications synchrone chopping of several stepper motor drivers may bedesirable to reduce acoustic interference. This can be done by forcing the oscillator ofthe TLE 4728 G by a pulse generator overdriving the oscillator loading currents(approximately ± 120 µA). In these applications low level should be between 0 V and0.8 V while high level should between 3 V and 5 V.

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 TLE 4728 G 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 decay

TLE 4728 G

Data Sheet 24 2004-03-01

during that time. To achieve maximum current accuracy such glitches at the phaseinputs should be avoided by proper control signals.

To lower EMI a ceramic capacitor of max. 3 nF is advisable from each output to GND.

Thermal Shut Down

To protect the circuit against thermal destruction, thermal shut down has beenimplemented.

Error Monitoring

The error outputs signal corresponding to the logic table the errors described below.

Logic Table

Overtemperature is implemented as pre-alarm; it appears approximately 20 K beforethermal shut down. To detect an open load, the recirculation of the inductive load iswatched. If there is no recirculation after a phase change-over, an internal error flipflopis set. Because in most kinds of short circuits there won’t flow any current through themotor, there will be no recirculation after a phase change-over, and the error flipflop foropen load will be set, too. Additionally an open load error is signaled after a phasechange-over during hold mode.

Only in the case of a short circuit to GND, the most probably kind of a short circuit inautomotive applications, the malfunction is signaled dominant (see d) in logic table) by aseparate error flag. Simultaneously the output current is disabled after 30 µs to preventdisturbances.

A phase change-over or putting both current control inputs of the affected bridge on highpotential resets the error flipflop. Being a separate flipflop for every bridge, the error canbe located in easy way.

Kind of Error Error Output

Error 1 Error 2

a) No error H H

b) Short circuit to GND H L

c) Open load 1)

1) Also possible: short circuit to + VS or short circuit of the load.

L H

d) b) and c) simultaneously H L

e) Temperature pre-alarm L L

TLE 4728 G

Data Sheet 25 2004-03-01

Package Outlines

P-DSO-24-9 (Plastic Dual Small Outline Package)

Lead width can be 0.61 max. in dambar areaDoes not include plastic or metal protrusion of 0.15 max. per side

Index Marking

1.27

+0.150.35

15.61

24

2)

-0.41)

12

0.2

13

24x0.1

2.65

MA

X.

0.2

-0.1

2.45

-0.2

0.4 +0.8

10.3 ±0.3

0.35 x 45˚

-0.27.6 1)

0.23

+0.0

9

MA

X.

8˚

1)

2)

Sorts of PackingPackage outlines for tubes, trays etc. are contained in our Data Book “Package Information”.

Dimensions in mmSMD = Surface Mounted Device