A2927: Dual Full-Bridge PWM Motor Driver

2927
DUAL FULL-BRIDGE
PWM MOTOR DRIVER
GND
LOGIC SUPPLY
40
PWM 1
GND
37
1
36
11
35
12
34
13
U
D
VBB
33
14
2
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.
T
C
38
9
10
32
15
31
Y
L
N
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.
O
R
P EO
D
C
E
N
U
E
N R
I
E
T
F
N
E
O
R
C
R
S
I
O
D F
—
30
16
PWM 2
29
28
RC 2
27
ENABLE
2
26
V REF 2 25
PHASE 2
I21 24
I20 23
OUT 2B 21
LOAD SUPPLY 22
SENSE 2 20
E2
19
OUT 2A 18
GND
EN 2
17
θ2
GND
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.
39
7
8
DUAL FULL-BRIDGE
PWM MOTOR DRIVER
VCC
ENABLE 1
RC1
41
PHASE 1
43
42
EN1
θ1
I11
2
VREF 1
3
1
OUT 1B
I10
4
44
SENSE 1
5
1
OUT 1A
E
6
PRELIMINARY INFORMATION
(Subject to change without notice)
September 16, 1997
Data Sheet
29319.23
2927
Dwg. PP-021
ABSOLUTE MAXIMUM RATINGS
at TJ ≤ +150°C
Motor Supply Voltage, VBB ................... 50 V
Output Current, IOUT ......................... ±1.5 A
Logic Supply Voltage, VCC ................... 7.0 V
Logic Input Voltage Range,
VIN ............................... -0.3 V to +7.0 V
Output Emitter Voltage, VE .................. 1.0 V
Package Power Dissipation,
PD ........................................ See Graph
Operating Temperature Range,
TA ................................. -20°C to +85°C
Storage Temperature Range,
TS ............................... -55°C to +150°C
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.
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
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.
Always order by complete part number: A2927SEB .
2927
DUAL FULL-BRIDGE
PWM MOTOR DRIVER
PWM CURRENT-CONTROL CIRCUITRY
VBB
CHANNEL 1
PIN NUMBERS
SHOWN.
22
OUT A
OUT
6
B
3
V REF 44
5
20 kΩ
÷10
E
SENSE –
4
40 kΩ
RC
10 kΩ
I0 2
R
I1 1
ONE
SHOT
+
S
SOURCE
DISABLE
41 RC
CC
R
C
T
T
Dwg. EP-007-4
12.5
T
R θJ
=6
10
/W
°C
ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS
TRUTH TABLE
Enable
Phase
OutA
OutB
L
L
H
H
L
X
H
L
Z
L
H
Z
X = Don’t care
Z = High impedance
7.5
5.0
2.5
R
θJA
= 35
°C/W
0
25
50
75
100
TEMPERATURE IN °C
125
150
Dwg. GP-020-1
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 1997 Allegro MicroSystems, Inc.
2927
DUAL FULL-BRIDGE
PWM MOTOR DRIVER
ELECTRICAL CHARACTERISTICS at TA = +25°C, VBB = 50 V, VCC = 5.0 V, VREF = 5.0 V (unless
otherwise noted).
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Output Drivers (OUTA or OUTB)
Motor Supply Range
VBB
IOUT = ±1.5 A, L = 15 mH
10
—
50
V
Output Leakage Current
ICEX
VOUT = VBB
—
<1.0
5.0
µA
VOUT = 0
—
<-1.0
-5.0
µA
Sink Driver, IOUT = +1.0 A*
—
0.5
0.7
V
Sink Driver, IOUT = +1.5 A*
—
0.8
0.9
V
Source Driver, IOUT = -1.0 A*
—
1.8
1.9
V
Source Driver, IOUT = -1.5 A*
—
1.9
2.0
V
Output Saturation Voltage
VCE(SAT)
Flyback Diode Forward Volt.
VF
IF = 1.5 A
—
1.6
2.0
V
Driver Supply Current
IBB(ON)
Both Bridges ON, No Load
—
6.5
9.0
mA
IBB(OFF)
Both Bridges OFF
—
4.0
4.0
mA
VIN(1)
All Inputs
2.4
—
—
V
VIN(0)
All Inputs
—
—
0.8
V
IIN(1)
VIN = 2.4 V
—
<1.0
20
µA
IIN(0)
VIN = 0.8 V
—
-3.0
-200
µA
Reference Voltage Range
VREF
Operating
1.5
—
7.5
V
Current Limit Threshold
VREF/VSENSE
I0 = I1 = 0.8 V
9.5
10
10.5
—
I0 = 2.4 V, I1= 0.8 V
13.5
15
16.5
—
I0 = 0.8 V, I1 = 2.4 V
25.5
30
34.5
—
—
170
—
°C
Control Logic
Input Voltage
Input Current
(at trip point)
Thermal Shutdown Temp.
TJ
Total Logic Supply Current
ICC(ON)
I0 = I1 = VEN = 0.8 V, No Load
—
90
105
mA
ICC(OFF)
I0 = I1 = 2.4 V, No Load
—
10
12
mA
Negative current is defined as coming out of (sourcing) the specified device pin.
Typical Data is for design information only.
* Pulse test (<10 ms).
2927
DUAL FULL-BRIDGE
PWM MOTOR DRIVER
APPLICATIONS INFORMATION
PWM OUTPUT CURRENT WAVEFORM
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.
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 (VSENSE) reaches the level
set at the comparator’s input:
V PHASE
+
I
OUT
0
–
I TRIP
ITRIP = VREF/10 RS
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 toff =
RTCT within the range of 20 kΩ to 100 kΩ
and 200 pF to 500 pF.
td
t off
Dwg. WM-003-1A
LOAD CURRENT PATHS
V
BB
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.
Special circuitry has been included to
prevent runaway current control when the
fixed OFF time (toff) is set too short. This
circuitry prevents the source driver from
being re-enabled until the load current has
decayed to below the ITRIP level.
RS
BRIDGE ON
SOURCE OFF
ALL OFF
Dwg. EP-006-14
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
2927
DUAL FULL-BRIDGE
PWM MOTOR DRIVER
CURRENT-CONTROL
TRUTH TABLE
I0
I1
Output Current
L
L
VREF /10 RS = ITRIP
H
L
VREF /15 RS = 2/3 ITRIP
L
H
VREF /30 RS = 1/3 ITRIP
H
H
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.
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 (VREF) provides continuous control of the peak load current for micro-stepping
applications, within the specified limits for VREF.
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)
18
28
29
17
0.032
0.026
0.319
0.291
0.695
0.685
0.021
0.013
0.656
0.650
0.319
0.291
0.050
INDEX AREA
BSC
39
7
40
0.020
44
1
2
6
0.656
0.650
MIN
0.695
0.685
0.180
0.165
Dwg. MA-005-44A in
Dimensions in Millimeters
(for reference only)
18
28
29
17
0.812
0.661
8.10
7.39
17.65
17.40
0.533
0.331
16.662
16.510
8.10
7.39
INDEX AREA
1.27
BSC
7
39
40
0.51
MIN
4.57
4.20
44
1
2
6
16.662
16.510
17.65
17.40
Dwg. MA-005-44A mm
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 (508) 853-5000
2927
DUAL FULL-BRIDGE
PWM MOTOR DRIVER
This page intentionally left blank
2927
DUAL FULL-BRIDGE
PWM MOTOR DRIVER
BRIDGE & HALF-BRIDGE DRIVERS
SELECTION GUIDE
IN ORDER OF 1) OUTPUT CURRENT AND 2) OUTPUT VOLTAGE
Features
Output Ratings *
Internal
Diodes
Outputs
Internal
Protection
Dual PWM Full Bridge
Dual PWM Full Bridge
X
X
Bipolar
Bipolar
X
X
3966
3968
45
45
45
Dual PWM Full Bridge
Dual PWM Full Bridge
Dual PWM Full Bridge
X
X
X
Bipolar
Bipolar
Bipolar
X
X
X
2916
2919
6219
±800
33
Dual PWM Full Bridge
X
Bipolar
X
3964
±900
14
3-Ø Back-EMF Controller/Driver
X
DMOS
X
8902-A
±1000
7.0
3-Ø Back-EMF Controller/Driver
X
NMOS
X
8984
±1300
50
PWM Full Bridge
X
Bipolar
X
3953
±1500
45
45
50
50
Dual PWM Full Bridge
Dual PWM Full Bridge
PWM Microstepping Full Bridge
PWM Microstepping Full Bridge
X
X
X
X
Bipolar
Bipolar
Darlington/Satlington™
Darlington/Satlington™
X
X
X
X
2917
2918
3955
3957
±2000
45
50
50
50
3-Ø Brushless Controller/Driver
Dual Full Bridge
PWM Full-Bridge
PWM Full-Bridge
X
X
X
X
Darlington
Darlington
Darlington
Darlington
X
X
X
X
2936
2998
3951
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
mA
V
Description
±650
30
30
±750
Part
Number †
* 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.
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 (508) 853-5000
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