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2918 DUAL FULL-BRIDGE PWM MOTOR DRIVER
2918
DUAL FULL-BRIDGE PWM MOTOR DRIVER
The A2918SWH and A2918SWV motor drivers are designed to drive both windings of a bipolar stepper motor or bidirectionally control two dc motors. All bridges are capable of sustaining 45 V and include internal pulse-width modulation (PWM) control of the output current to 1.5 A. For PWM current control, the maximum output current is determined by the user's selection of a reference voltage and sensing resistor. A PHASE input to each bridge determines load current direction. Active low ENABLE inputs control the four drivers in each bridge. The bridges include both ground clamp and flyback diodes for protection against inductive transients. 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 A2918SWH/V are supplied in an 18-lead power-tab package with staggered lead forming. The tab is internally insulated from the device and requires no external isolation. The A2918SWH/V are available for operation from -40C to +85C. To order, change the suffix from 'S-' to 'E-'. These devices are also available on special order for operation to +125C.
Data Sheet 29319.24A
OUT1A OUT2A E2 OUT2B LOAD SPLY SENSE 2 ENABLE2 PHASE2 RC2 GROUND LOGIC SPLY RC1 PHASE1 ENABLE1 REFERENCE SENSE1 OUT1B E1
1 2 3 4 5 6 7 8 9 10
VCC PWM 2 2 VBB 1
11 12 13
PWM 1
14
VREF
TSD
15 16 17 18
Dwg. PP-051
ABSOLUTE MAXIMUM RATINGS
at TJ +150C
FEATURES
s s s s s s s 1.5 A Continuous Output Current 45 V Output Sustaining Voltage Internal PWM Current Control Low Output Saturation Voltage Internal Clamp Diodes Internal Thermal Shutdown Circuitry Similar to Dual PBL3718 or Dual PBL3770
Motor Supply Voltage, VBB . . . . . . . . . 45 V Output Current, IOUT (t w20 s) . . 1.75 A (Continuous) . . . . . . . . . . . . . . 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, V E . . . . . . . . . 1.5 V Package Power Dissipation, PD . . . . . . . . . . . . . . . . . . . . See Graph Operating Temperature Range, TA . . . . . . . . . . . . . . . . -20C to +85C Storage Temperature Range, TS . . . . . . . . . . . . . . . -40C to +150C
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 +150C.
Always order by complete part number: Part Number A2918SWH A2918SWV Application For Horizontal Mount For Vertical Mount
2918 DUAL FULL-BRIDGE PWM MOTOR DRIVER
FUNCTIONAL BLOCK DIAGRAM
LOGIC SUPPLY OUT 1B LOAD SUPPLY OUT 2A OUT 1A OUT 2B
11 VCC
1
17
5
2
4
TSD VBB
PWM 1
1
2
ENABLE1 14
PWM 2
PHASE 1 13
8
PHASE 2
7
ENABLE2
SOURCE DISABLE - + /10 VREF /10 - +
SOURCE DISABLE
ONE SHOT
ONE SHOT
SENSE 1
SENSE 2
E1
E2
RC1
RT CT
CC
RS
REFERENCE
GROUND
RC
RS
RC2
RT
Dwg. FP-033
12
16
R C 18
15
10
3
6
9
CC
CT
10
ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS
8
R JT /W C =9
6
TRUTH TABLE
Enable L L H Phase H L X OutA H L Z OutB L H Z
4
R
JA
2
=2 8C /W
X = Don't care Z = High impedance
0 25 50 75 100 TEMPERATURE IN C 125 150
Dwg. GP-043
115 Northeast Cutoff, Box 15036 W Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright (c) 1991, 1993, Allegro MicroSystems, Inc.
2918 DUAL FULL-BRIDGE PWM MOTOR DRIVER
ELECTRICAL CHARACTERISTICS at TA = +25C, VBB = 45 V, VCC = 4.75 V to 5.25 V, VREF = 5.0 V (unless otherwise noted).
Limits Characteristic Output Drivers (OUTA or OUTB) Motor Supply Range Output Leakage Current V BB ICEX VOUT = VBB VOUT = 0 Output Sustaining Voltage Output Saturation Voltage VCE(sus) VCE(SAT) IOUT = 1.5 A, L = 3.0 mH Sink Driver, IOUT = +1.0 A Sink Driver, IOUT = +1.5 A Source Driver, IOUT = -1.0 A Source Driver, IOUT = -1.5 A Clamp Diode Leakage Current Clamp Diode Forward Voltage Driver Supply Current IR VF IBB(ON) IBB(OFF) Control Logic Input Voltage VIN(1) VIN(0) Input Current IIN(1) IIN(0) Reference Voltage Range Current Limit Threshold Thermal Shutdown Temp. Total Logic Supply Current VREF VREF /VSENSE TJ ICC(ON) ICC(OFF) VEN = 0.8 V, No Load VEN = 2.4 V, No Load All Inputs All Inputs VIN = 2.4 V VIN = 0.8 V Operating At Trip Point 2.4 -- -- -- 1.5 9.5 -- -- -- -- -- <1.0 -3.0 -- 10 170 105 10 -- 0.8 20 -200 VCC 10.5 -- 140 12 V V A A V -- C mA mA VR = 45 V IF = 1.5 A Both Bridges ON, No Load Both Bridges OFF 10 -- -- 45 -- -- -- -- -- -- -- -- -- <1.0 <-1.0 -- 0.7 0.9 1.8 1.9 <1.0 1.6 12 8.0 45 50 -50 -- 0.8 1.1 2.0 2.2 50 2.0 15 10 V A A V V V V V A V mA mA Symbol Test Conditions Min. Typ. Max. Units
Negative current is defined as coming out of (sourcing) the specified device pin. Typical Data is for design information only.
2918 DUAL FULL-BRIDGE PWM MOTOR DRIVER
PWM OUTPUT CURRENT WAVEFORM APPLICATIONS INFORMATION
PWM Current Control The A2918SWH/V dual bridges are 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 ), an internal comparator, and an internal monostable multivibrator. When the bridge is turned ON, current increases in the motor winding and it is sensed by RS until the sense voltage (V SENSE) reaches the level set at the comparator's input: ITRIP = VREF /10 RS
Dwg. WM-003-1A
V PHASE
+ I OUT 0 -
I TRIP
td
t off
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 internal logic and switching delays. This delay (td) is 2 s typically. After turn-off, the motor current decays, circulating through the ground clamp diode and sink transistor. The source driver's OFF time toff, 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 k to 100 k and 200 pF to 500 pF. When the source driver is re-enabled, the winding current (the sense voltage) again is 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 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. 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 possible erroneous current control or high-frequency oscillations. An external RC CC low-pass filter may be used to delay the action of the comparator, and thus ignore turn-on spikes.
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2918 DUAL FULL-BRIDGE PWM MOTOR DRIVER
General To avoid excessive voltage spikes on the LOAD SUPPLY pin (VBB), a large-value capacitor (47 F) should be connected from VBB to the ground pin as close as possible to the device. Under no circumstances should the voltage at VBB exceed 45 V. The PHASE input to each bridge determines the direction motor winding current flows. An internally generated deadtime, of approximately 3 s, prevents crossover currents that can occur when switching the PHASE input. All four drivers in the bridge output can be turned OFF, with VEN 2.4, resulting in a fast current decay through the internal ground clamp and flyback diodes. The fast current decay is desirable in half-step and high-speed applications. 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. Thermal protection circuitry turns OFF all drivers when the junction temperature reaches approximately +170C. It is intended only 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 re-enabled when the junction temperature cools to approximately +145C.
LOAD CURRENT PATHS
V BB
RS
BRIDGE ON SOURCE OFF ALL OFF
Dwg. EP-006-1
2918 DUAL FULL-BRIDGE PWM MOTOR DRIVER
A2918SWH for horizontal mounting
Dimensions in Inches (for reference only)
1.228 1.213 0.968 0.953 0.653 0.638 0.196 0.182 0.126 x 0.150 0.070 0.063
o 0.131
0.120
0.637 0.623
0.397 0.382 0.204 0.158
0.519 0.504
0.141 0.095 0.022
1
18
1.240 1.225
0.091 0.083 0.260 0.213 0.318 0.272
0.086 0.040
0.033 0.022
0.066 0.016
Dwg. MP-006 in
Dimensions in Millimeters (controlling dimensions)
31.2 30.8 3.35 3.05 24.6 24.2 16.6 16.2 3.2 x 3.8 5.0 4.6 1.8 1.6
16.2 15.8
10.1 9.7 5.2 4.0
13.2 12.8
3.6 0.57 2.4 0.54
1
18
31.5 31.1
2.3 2.1 6.6 5.4 8.1 6.9
2.2 1.0
0.85 0.55
1.68 0.4
Dwg. MP-006 mm
NOTES: 1. 2.
Exact body and lead configuration at vendor's option within limits shown. Lead spacing tolerance is non-cumulative.
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2918 DUAL FULL-BRIDGE PWM MOTOR DRIVER
A2918SWV for vertical mounting
Dimensions in Inches (for reference only)
1.228 1.213 0.968 0.953 0.131 0.120 0.653 0.638 0.196 0.182 0.126 x 0.150 0.070 0.063
0.637 0.623
0.397 0.382
0.519 0.504 0.283 0.245 0.421 0.363 0.104 0.089
0.033 0.022
1
0.066 0.027 1.240 1.225
18
0.022 0.185 0.130
Dwg. MP-004 in
Dimensions in Millimeters (controlling dimensions)
31.2 30.8 24.6 24.2 3.35 3.05 16.6 16.2 3.2 x 3.8 5.0 4.6 1.8 1.6
16.2 15.8
10.1 9.7
13.2 12.8
7.2 6.2 2.65 2.25
10.7 9.2 0.85 0.55
1
1.68 0.7 31.5 31.1
18
0.57 0.54
4.7 3.3
Dwg. MP-004 mm
NOTES: 1. 2.
Exact body and lead configuration at vendor's option within limits shown. Lead spacing tolerance is non-cumulative.
2918 DUAL FULL-BRIDGE PWM MOTOR DRIVER
MOTOR DRIVERS SELECTION GUIDE
Function Output Ratings * 2.0 A 10 mA 20 mA 20 mA 900 mA 400 mA 300 mA 900 mA 4.0 A 1.0 A 750 mA 1.5 A 750 mA 2.0 A 2.0 A 1.3 A 1.5 A 800 mA 650 mA 750 mA 1.8 A 1.25 A 1A 1.2 A 500 mA 800 mA 350 mA Part Number INTEGRATED CIRCUITS FOR BRUSHLESS DC MOTORS 3-Phase Controller/Drivers Hall-Effect Latched Sensors 2-Phase Hall-Effect Sensor/Controller Hall-Effect Complementary-Output Sensor 2-Phase Hall-Effect Sensor/Driver 2-Phase Hall-Effect Sensor/Driver Hall-Effect Complementary-Output Sensor/Driver 3-Phase Back-EMF Controller/Driver 3-Phase Controller/DMOS Driver 3-Phase Back-EMF Controller/Driver PWM Current-Controlled Dual Full Bridge PWM Current-Controlled Dual Full Bridges PWM Current-Controlled Dual Full Bridge Dual Full-Bridge Driver PWM Current-Controlled Full Bridge PWM Current-Controlled Full Bridge PWM Current-Controlled Microstepping Full Bridges PWM Current-Controlled Dual Full Bridge PWM Current-Controlled Dual Full Bridge PWM Current-Controlled Dual Full Bridge Unipolar Stepper-Motor Quad Driver Unipolar Stepper-Motor Translator/Driver Unipolar Stepper-Motor Quad Drivers Unipolar Microstepper-Motor Quad Driver Voice-Coil Motor Driver Voice-Coil Motor Driver Voice-Coil (and Spindle) Motor Driver * 45 V 24 V 25 V 25 V 14 V 26 V 60 V 14 V 14 V 7V 45 V 45 V 45 V 50 V 50 V 50 V 50 V 33 V 30 V 45 V 50 V 50 V 46 V 46 V 6V 16 V 7V 2936 and 2936-120 3175 and 3177 3235 3275 3625 3626 5275 8902-A 8925 8984 2916 2917 and 2918 2919 2998 3952 3953 3955 and 3957 3964 3966 and 3968 6219 2544 5804 7024 and 7029 7042 8932-A 8958 8984
INTEGRATED BRIDGE DRIVERS FOR DC AND BIPOLAR STEPPER MOTORS
OTHER INTEGRATED CIRCUIT & PMCM MOTOR DRIVERS
Current is maximum specified test condition, voltage is maximum rating. See specification for sustaining voltage limits or over-current protection voltage limits. Negative current is defined as coming out of (sourcing) the output. 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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