Datasheet A2927SEB Datasheet (Allegro)

2927

DUAL FULL-BRIDGE
PWM MOTOR DRIVER

PRELIMINARY INFORMATION

(Subject to change without notice)

September 16, 1997

REF 1

V

44

PWM 1

24

21

I

1

PHASE

43

θ

PWM 2

25

REF 2

V

ENABLE

424140

1

θ

26

PHASE

1

1

LOGIC SUPPLY

RC

1

CC

V

EN

2

2

EN

27

28

2

2

2

RC

ENABLE

Dwg. PP-021

1

1A

OUT

6

GND

7

8

9

10

11

12

13

14

15

16

GND

17 29

18

2A

OUT

1B

1

E

SENSE

4

5

1

2

19

20

2

2

E

SENSE

OUT

3

21

2B

OUT

10

I

I

2

1

BB

V

22

23

20

I

LOAD SUPPLY

11

Data Sheet

29319.23

2927

DUAL FULL-BRIDGE

PWM MOTOR DRIVER

The A2927SEB motor driver is designed to drive both windings of a
bipolar stepper motor or bidirectionally control two dc motors. Both
bridges are capable of sustaining 50 V and include internal pulse-width
modulation (PWM) control of the output current to 1.5 A.

GND

39

38

37

36

35

34

33

32

31

30

GND

For PWM current control, the maximum output current is determined
by the user’s selection of a reference voltage and sensing resistor. Two
logic-level inputs select output current limits of 0, 33%, 67%, or 100%
of the maximum level. A PHASE input to each bridge determines load
current direction. Active-low ENABLE inputs control the four drivers in
each bridge.

Internally generated delays prevent cross-over currents when
switching current direction. Special power-up sequencing is not required.
Thermal protection circuitry disables the outputs if the chip temperature
exceeds safe operating limits.

The A2927SEB is supplied in a 44-lead power PLCC for surface­mount applications. Its batwing construction provides for maximum
package power dissipation in the smallest possible construction.

ABSOLUTE MAXIMUM RATINGS

at T

≤ +150°C

J

Motor Supply Voltage, VBB................... 50 V

Output Current, I
Logic Supply Voltage, V

......................... ±1.5 A

OUT

................... 7.0 V

CC

Logic Input Voltage Range,

V

............................... -0.3 V to +7.0 V

IN

Output Emitter Voltage, V

.................. 1.0 V

E

Package Power Dissipation,

P

........................................ See Graph

D

Operating Temperature Range,

T

................................. -20°C to +85°C

A

DISCONTINUED PRODUCT

Storage Temperature Range,

T

............................... -55°C to +150°C

S

Output current rating may be limited by duty cycle,
ambient temperature, and heat sinking. Under any
set of conditions, do not exceed the specified peak
current rating or a junction temperature of +150°C.

— FOR REFERENCE ONLY

FEATURES

■ 1.5 A Output Current

■ 50 V Output Sustaining Voltage

■ Internal Flyback Diodes

■ Digital Control of Output Current

■ Undervoltage Lockout

■ Internal Thermal Shutdown Circuitry

Always order by complete part number: A2927SEB .

2927

22

365

4412

1

44

DUAL FULL-BRIDGE
PWM MOTOR DRIVER

PWM CURRENT-CONTROL CIRCUITRY

CHANNEL 1
PIN NUMBERS
SHOWN.

I

0

I

1

V

REF

40 kΩ

20 kΩ

10 kΩ

÷10

OUT

V

BB

A

OUT

B

E

SENSE

R

C

R

S

–
+

C

C

ONE

SHOT

RC

R

T

SOURCE
DISABLE

C

T

Dwg. EP-007-4

TRUTH TABLE

12.5

R = 6°C/W

θJT

10

7.5

5.0

2.5

0

ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS

25

R = 35°C/W

θJA

50 75 100 125 150

TEMPERATURE IN °C

Dwg. GP-020-1

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
Copyright © 1997 Allegro MicroSystems, Inc.

Enable Phase Out

A

Out

LHHL
LLLH

HXZZ

X = Don’t care
Z = High impedance

B

2927

DUAL FULL-BRIDGE
PWM MOTOR DRIVER

ELECTRICAL CHARACTERISTICS at T

= +25°C, V

A

= 50 V, VCC = 5.0 V, V

BB

= 5.0 V (unless

REF

otherwise noted).

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units
Output Drivers (OUT

Motor Supply Range V
Output Leakage Current I

Output Saturation Voltage V

Flyback Diode Forward Volt. V
Driver Supply Current I

Control Logic

or OUTB)

A

BB

CEX

CE(SAT

F

BB(ON)

I

BB(OFF)

I

= ±1.5 A, L = 15 mH 10 — 50 V

OUT

V

= V

OUT

BB

V

= 0 — <-1.0 -5.0 µA

OUT

)

Sink Driver, I
Sink Driver, I
Source Driver, I
Source Driver, I

= +1.0 A* — 0.5 0.7 V

OUT

= +1.5 A* — 0.8 0.9 V

OUT

= -1.0 A* — 1.8 1.9 V

OUT

= -1.5 A* — 1.9 2.0 V

OUT

— <1.0 5.0 µA

IF = 1.5 A — 1.6 2.0 V
Both Bridges ON, No Load — 6.5 9.0 mA
Both Bridges OFF — 4.0 4.0 mA

Input Voltage V

Input Current I

Reference Voltage Range V
Current Limit Threshold V

IN(1)

V

IN(0)

IN(1)

I

IN(0)

REF

REF/VSENSE

(at trip point)

Thermal Shutdown Temp. T
Total Logic Supply Current I

Negative current is defined as coming out of (sourcing) the specified device pin.
Typical Data is for design information only.
* Pulse test (<10 ms).

J

CC(ON)

I

CC(OFF)

All Inputs 2.4 — — V
All Inputs — — 0.8 V
V

= 2.4 V — <1.0 20 µA

IN

VIN = 0.8 V — -3.0 -200 µA
Operating 1.5 — 7.5 V
I0 = I1 = 0.8 V 9.5 10 10.5 —
I

= 2.4 V, I1= 0.8 V 13.5 15 16.5 —

0

I

= 0.8 V, I1 = 2.4 V 25.5 30 34.5 —

0

I0 = I1 = VEN = 0.8 V, No Load — 90 105 mA
I0 = I1 = 2.4 V, No Load — 10 12 mA

— 170 — °C

2927

DUAL FULL-BRIDGE
PWM MOTOR DRIVER

APPLICATIONS INFORMATION

PWM CURRENT CONTROL:

The UDN2927EB dual bridge is designed
to drive both windings of a bipolar stepper
motor. Output current is sensed and con­trolled independently in each bridge by an
external sense resistor (RS), internal com­parator, and monostable multivibrator.

V

PWM OUTPUT CURRENT WAVEFORM

PHASE

When the bridge is turned ON, current
increases in the motor winding and it is
sensed by the external sense resistor until
the sense voltage (V

) reaches the level

SENSE

set at the comparator’s input:

I

TRIP

= V

REF

/10 R

S

The comparator then triggers the mon­ostable which turns OFF the source driver of
the bridge. The actual load current peak will
be slightly higher than the trip point (espe­cially for low-inductance loads) because of
the internal logic and switching delays. This
delay (td) is typically 2 µs. After turn-off, the
motor current will normally decay, circulating
through the external ground clamp diode and
sink transistor. The source driver’s OFF time
(and therefore the magnitude of the current
decrease) is determined by the monostable’s
external RC timing components, where t

=

off

RTCT within the range of 20 kΩ to 100 kΩ
and 200 pF to 500 pF.

When the source driver is re-enabled, the
winding current (the sense voltage) is again
allowed to rise to the comparator’s threshold.
This cycle repeats itself, maintaining the
average motor winding current at the desired
level.

+

I

0

OUT

–

I

TRIP

t

d

t

off

Dwg. WM-003-1A

LOAD CURRENT PATHS

V

BB

Special circuitry has been included to
prevent runaway current control when the
fixed OFF time (t

) is set too short. This

off

circuitry prevents the source driver from
being re-enabled until the load current has
decayed to below the I

TRIP

level.

R

S

BRIDGE ON
SOURCE OFF
ALL OFF

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

Dwg. EP-006-14

2927

DUAL FULL-BRIDGE
PWM MOTOR DRIVER

CURRENT-CONTROL

TRUTH TABLE

I

0

LLV
HLV
LHV
HH 0

Loads with high distributed capacitances may result in
high turn-ON current peaks. This peak (appearing across
RS) will attempt to trip the comparator, resulting in errone­ous current control or high-frequency oscillations. An
external RCCC low-pass filter may be needed to delay the
action of the comparator.

LOGIC CONTROL OF OUTPUT CURRENT:

Two logic level inputs (I0 and I1) allow digital selection
of the motor winding current at 100%, 67%, 33%, or 0% of
the maximum level per the table. The 0% output current
condition turns OFF all drivers in the bridge and can be
used as an output enable function. These logic level
inputs greatly enhance the implementation of µP-con­trolled drive formats.

During half-step operations, the I0 and I1 inputs allow
the µP to control the motor at a constant torque between
all positions in an eight-step sequence. This is accom­plished by digitally selecting 100% drive current when only
one phase is ON and 67% drive current when two phases
are ON.

The logic control inputs can also be used to select a
reduced current level (and reduced power dissipation) for
‘hold’ conditions and/or increased current (and available
torque) for start-up conditions.

I

1

Output Current

/10 RS = I

REF

/15 RS = 2/3 I

REF

/30 RS = 1/3 I

REF

TRIP

TRIP

TRIP

GENERAL:

Both bridges have internal flyback diodes (connected
from the outputs to VBB) for protection against inductive
transients. External ground-clamp diodes (connected
from the outputs to ground) are required; Schottky
ground-clamp diodes are recommended to minimize on­chip power dissipation.

To avoid excessive voltage spikes on the LOAD
SUPPLY terminal (VBB), a large-value capacitor (≥47 µF)
should be connected from VBB to ground as close as
possible to the device. Under no circumstances should
the voltage at LOAD SUPPLY exceed 50 V. A low-value
(0.1 µF) ceramic capacitor at this terminal may be used
for high-frequency noise suppression.

The PHASE input to each bridge determines the
direction motor winding current flows. An internally
generated deadtime (approximately 3 µs) prevents
crossover currents that can occur when switching the
PHASE input.

All four drivers in the bridge output can be turned OFF
(VEN ≥ 2.4 V or I0 = I1 ≥ 2.4 V), resulting in a fast current
decay through the internal flyback and external ground­clamp diodes. The fast current decay is desirable in half­step and high-speed applications. All logic inputs float
high; the ENABLE input must be tied low if it is not used.

Varying the reference voltage (V

) provides continu-

REF

ous control of the peak load current for micro-stepping
applications, within the specified limits for V

REF

.

Thermal protection circuitry turns OFF all drivers
when the junction temperature reaches approximately
+170°C. It is only intended to protect the device from
failures due to excessive junction temperature and should
not imply that output short circuits are permitted. The
output drivers are reenabled when the junction tempera­ture cools to approximately +160°C.

2927

DUAL FULL-BRIDGE
PWM MOTOR DRIVER

Dimensions in Inches

(controlling dimensions)

28

18

0.319

0.291

0.319

0.291

8.10

7.39

0.021

0.013

0.050

BSC

0.020

MIN

0.180

0.165

29

0.032

0.026

0.695

0.685

0.656

0.650

39

40

Dimensions in Millimeters

(for reference only)

28

29

0.812

0.661

0.656

0.650

144

0.695

0.685

INDEX AREA

2

17

7

6

Dwg. MA-005-44A in

18

17

0.51

MIN

17.65

17.40

16.662

16.510

39

40

16.662

16.510

8.10

7.39

0.533

0.331

1.27

BSC

4.57

4.20

NOTES: 1. Exact body and lead configuration at vendor’s option within limits shown.

2. Lead spacing tolerance is non-cumulative.

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

144

17.65

17.40

INDEX AREA

2

7

6

Dwg. MA-005-44A mm

2927

DUAL FULL-BRIDGE
PWM MOTOR DRIVER

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2927

DUAL FULL-BRIDGE
PWM MOTOR DRIVER

BRIDGE & HALF-BRIDGE DRIVERS

SELECTION GUIDE

IN ORDER OF 1) OUTPUT CURRENT AND 2) OUTPUT VOLTAGE

Output Ratings *

Internal Internal Part

mA V Description Diodes Outputs Protection Number †

±650 30 Dual PWM Full Bridge X Bipolar X 3966

30 Dual PWM Full Bridge X Bipolar X 3968

±750 45 Dual PWM Full Bridge X Bipolar X 2916

45 Dual PWM Full Bridge X Bipolar X 2919
45 Dual PWM Full Bridge X Bipolar X 6219

±800 33 Dual PWM Full Bridge X Bipolar X 3964
±900 14 3-Ø Back-EMF Controller/Driver X DMOS X 8902-A

Features

±1000 7.0 3-Ø Back-EMF Controller/Driver X NMOS X 8984
±1300 50 PWM Full Bridge X Bipolar X 3953
±1500 45 Dual PWM Full Bridge X Bipolar X 2917

45 Dual PWM Full Bridge X Bipolar X 2918
50 PWM Microstepping Full Bridge X
50 PWM Microstepping Full Bridge X

±2000 45 3-Ø Brushless Controller/Driver X Darlington X 2936

50 Dual Full Bridge X Darlington X 2998
50 PWM Full-Bridge X Darlington X 3951
50 PWM Full-Bridge X Darlington X 3952

±3000 45 PWM Control X Darlington – 2962
±3400 45 PWM Control X Bipolar X 2961
±4000 14 3-Ø Brushless Controller/Driver X DMOS X 8925

* Current is maximum specified test condition, voltage is maximum rating. See specification for sustaining voltage limits or over­current protection voltage limits.

† Complete part number includes additional characters to indicate operating temperature range and package style.

Darlington/Satlington™
Darlington/Satlington™

X 3955
X 3957

Allegro MicroSystems, Inc. reserves the right to make, from time to time, such departures from the

detail specifications as may be required to permit improvements in the design of its products.

The information included herein is believed to be accurate and reliable. However, Allegro
MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or other
rights of third parties which may result from its use.

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]