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Details, datasheet, quote on part number:2918
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Datasheet text preview:
2918
OUT1A OUT2A E2 OUT2B LOAD SPLY SENSE 2
1 2 3 4 5 6 7 8 9
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.
2
ENABLE2 PHASE2 RC2
GROUND LOGIC SPLY
REFERENCE
ABSOLUTE MAXIMUM RATINGS
at TJ +150°C
Motor Supply Voltage, VBB . . . . . . . . . 45 V Output Current, IOUT (tw20 µs) . . ±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, VE . . . . . . . . . 1.5 V Package Power Dissipation, PD . . . . . . . . . . . . . . . . . . . . See Graph Operating Temperature Range, TA . . . . . . . . . . . . . . . . -20°C to +85°C Storage Temperature Range, TS . . . . . . . . . . . . . . . -40°C to +150°C
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.
T C. U LY DN O O gn R si P E de D NC w EE e U R rn IN E fo TFB NEE O R 17 C R 29 IS O N D F UD -- Use
PWM 2 VBB
Data Sheet 29319.24A
10 11 12
1
VCC
RC1
PHASE1
13 14 15 16 17 18
PWM 1
ENABLE1
VREF
TSD
SENSE1 OUT1B E1
Dwg. PP-051
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 -40°C to +85°C. To order, change the suffix from 'S' to 'E'. These devices are also available on special order for operation to +125°C.
FEATURES
I I I I I I I
± 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
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
PWM 2
PHASE 1 13
8
PHASE 2
ENABLE1 14
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 18 C
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 8°C /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 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 1991, 1993, Allegro MicroSystems, Inc.
2918
DUAL FULL-BRIDGE PWM MOTOR DRIVER
ELECTRICAL CHARACTERISTICS at TA = +25°C, 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 IC E X VOUT = VBB VOUT = 0 Output Sustaining Voltage Output Saturation Voltage V CE(sus) V CE(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 I BB(ON) IB B ( O F F ) Control Logic Input Voltage V IN(1) V IN(0) Input Current II N ( 1 ) II N ( 0 ) Reference Voltage Range Current Limit Threshold Thermal Shutdown Temp. Total Logic Supply Current VR E F V REF / VSENSE TJ I CC(ON) IC C ( O F F ) 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 VC C 10.5 -- 140 12 V V µA µA 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 µA µA V V V V V µA 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.
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2918
DUAL FULL-BRIDGE PWM MOTOR DRIVER
PWM OUTPUT CURRENT WAVEFORM APPLICATIONS INFORMATION
PWM Current Control
V PHASE
+ I OUT 0
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 (VSENSE) reaches the level set at the comparator's input: ITRIP = VREF/10 RS
Dwg. WM-003-1A
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 µs 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 RCCC 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 µF) 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 µs, 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 +170°C. 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 +145°C.
LOAD CURRENT PATHS
V BB
RS
BRIDGE ON SOURCE OFF ALL OFF
Dwg. EP-006-1
The products described here are manufactured in Japan by Sanken Electric Co., Ltd. for sale by Allegro MicroSystems, Inc. Sanken Electric Co., Ltd. and Allegro MicroSystems, Inc. reserve the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of their products. Therefore, the user is cautioned to verify that the information in this publication is current before placing any order. These products are not authorized for use as critical components in life-support appliances, devices, or systems without express written approval. The information included herein is believed to be accurate and reliable. However, Sanken Electric Co., Ltd. and Allegro MicroSystems, Inc. assume no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.
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