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UDN2916A
STEPPER MOTOR DRIVER
ADVANCE DATA
ABLE TO DRIVE BOTH WINDINGS OF BIPOLAR STEPPER MOTOR OUTPUT CURRENT UP TO 750mA EACH WINDING WIDE VOLTAGE RANGE 10V TO 50V HALF-STEP, FULL-STEP AND MICROSTEPPING MODE BUILT-IN PROTECTION DIODES INTERNAL PWM CURRENT CONTROL LOW OUTPUT SATURATION VOLTAGE DESIGNED FOR UNSTABILIZED MOTOR SUPPLY VOLTAGE INTERNAL THERMAL SHUTDOWN DESCRIPTION The UDN2916A is a bipolar monolithic integrated circuits intended to control and drive both winding of a bipolar stepper motor or bidirectionally control two DC motors. The UDN2916A with a few external components form a complete control and drive circuit for LSTTL or microprocessor controlled stepper motor system. The power stage is a dual full bridge capable of sustaining 50V and including four diodes for current recirculation. BLOCK DIAGRAM
Powerdip 20+2+2 ORDERING NUMBER: UDN2916A
A cross conduction protection is provided to avoid simultaneous cross conduction during switching current direction. An internal pulse-width-modulation (PWM) controls the output current to 750mA with peak startup current up to 1A. Wide range of current control from 750mA (each bridge) is permitted by means of two logic inputs and an external voltage reference. A phase input to each bridge determines the load current direction. A thermal protection circuitry disables the outputs if the chip temperature exceeds safe operating limits.
November 1991
ThAdvanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
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UDN2916A
PIN CONNECTION (Top view)
PIN FUNCTIONS
N 1;2 3;23 4;22 Name OUTPUT A SENSE RESISTOR COMPARATOR INPUT See pins 5;21 Connection to Lower Emitters of Output Stage for Insertion of Current Sense Resistor Input connected to the comparators. The voltage across the sense resistor is feedback to this input throught the low pass filter RC CC. The higher power transistors are disabled when the sense voltage exceeds the reference voltage of the selected comparator. When this occurs the current decays for a time set by RT C T (toff = 1.1 RT CT). See fig. 1. Output Connection. The output stage is a "H" bridge formed by four transistors and four diodes suitable for switching applications. See pins 7;18 Ground Connection. With pins 6 and 19 also conducts heat from die to printed circuit copper. See INPUT 1 (pins 9;17) These pins and pins 8;20 (INPUT 0) are logic inputs which select the outputs of the comparators to set the current level. Current also depends on the sensing resistor and reference voltage. See Funcional Description. This TTL-compatible logic inputs sets the direction of current flow through the load. A high level causes current to flow from OUTPUT A (source) to OUTPUT B (sink). A schmitt trigger on this input provides good noise immunity and a delay circuit prevents output stage short circuits during switching. A voltage applied to this pin sets the reference voltage of the comparators, this determining the output current (also thus depending on Rs and the two inputs INPUT 0 and INPUT 1). A parallel RC network connected to this pin sets the OFF time of the higher power transistors. The pulse generator is a monostable triggered by the output of the comparators (toff = 1.1 RT CT). Supply Voltage Input for Logic Circuitry Supply Voltage Input for the Output Stages. Function
5;21 6;19 7;18 8;20 9;17
OUTPUT B GROUND GROUND INPUT 0 INPUT 1
10;16
PHASE
11;15
REFERENCE VOLTAGE
12;14
RC
13 24 2/8
Vss - LOGIC SUPPLY VS - LOAD SUPPLY
UDN2916A
ABSOLUTE MAXIMUM RATINGS
Symbol VS Io Io VSS VIN Vsense TJ Top Tstg Supply Voltage Output Current (peak) Output Current (continuous) Logic Supply Voltage Logic Input Voltage Range Sense Output Voltage Junction Temperature Operating Temperature Range Storage Temperature Range Parameter Value 50 1 0.75 7 -0.3 to +7 1.5 +150 0 to 70 -55 to +150 Unit V A A V V V C C C
THERMAL DATA
Symbol Description Max Max Value 14 60 Unit C/W C/W R thj-case Thermal Resistance Junction-case R thj-ambient Thermal Resistance Junction-ambient
ELECTRICAL CHARACTERISTICS (Tamb = 25C, Ttab 70C, VS = 50V, VSS = 4.75V to 5.25V, VREF = 5V; unless otherwise specified) See fig. 3.
Symbol Parameter Test Condition Min. Typ. Max. Unit
OUTPUT DRIVERS (OUTA or OUTB)
VS ICEX VCE(sat) Motor Supply Range Output Leakage Current Output Saturation Voltage VOUT = Vs VOUT = 0 Sink Driver, IOUT = +500mA Sink Driver, IOUT = +750mA Source Driver, IOUT = -500mA Source Driver, IOUT = -750mA VR = 50V Sink Diode Source Diode IF =750mA Both Bridges ON, No Load Both Bridges OFF 10 <1 <-1 0.3 0.7 1.1 1.3 <1 1 1 8 6 50 50 -50 0.6 1 1.4 1.6 50 1.5 1.5 15 10 V A A V V V V A V V mA mA
IR VF IS(on) IS(off)
Clamp Diode Leakage Current Clamp Diode Forward Voltage Driver Supply Current Driver Supply Current
CONTROL LOGIC
VIN(H) VIN(L) IIN(H) IIN(L) VREF ISS(ON) ISS(OFF) Input Voltage Input Voltage Input Current Input Current Reference Voltage Total Logic Supply Current Total Logic Supply Current All Inputs All Inputs VIN = 2.4V VIN = 0.84V Operating Io = I1 = 0.8V, No Load Io = I1 = 2.4V, No Load 2.4 1.5 <1 -3 54 10 0.8 20 -200 7.5 64 14 V V A A V mA mA
COMPARATORS
VREF / Vsense Current Limit Threshold (at trip point Io = I1 = 0.8V Io = 2.4V, I1 = 0.8V Io = 0.8V, I1 = 2.4V toff td Cutoff Time Turn Off Delay Rt = 56K Ct = 820pF Fig. 1 9.5 13.5 25.5 10 15 30 50 1 10.5 16.5 34.5 s s
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UDN2916A
ELECTRICAL CHARACTERISTICS (Continued)
Symbol Parameter Test Condition Min. Typ. Max. Unit
PROTECTION
TJ Thermal Shutdown Temperature 170 C
Figure 1
FUNCTIONAL DESCRIPTION The circuit is intended to drive both windings of a bipolar stepper motor. The peak current control is generated through switch mode regulation. There is a choice of three different current levels with the two logic inputs I01 - I11 for winding 1 and I02 - I12 for winding 2. The current can also be switched off completely Input Logic (I0 and I1) The current level in the motor winding is selected with these inputs. (See fig. 2) If any of the logic inputs is left open, the circuit will treat it has a high level input.
Io H L H L I1 H H L L Current Level No Current Low Current 1/3 Io max Medium Current 2/3 Io max Maximum Current Io max
in the windings, depending on the motor connections. The signal is fed through a Schmidt-trigger for noise immunity, and through a time delay in order to guarantee that no short-circuit occurs in the output stage during phase-shift. High level on the PHASE input causes the motor current flow from Out A through the winding to Out B Current Sensor This part contains a current sensing resistor (RS), a low pass filter (RC, CC) and three comparators. Only one comparator is active at a time. It is activated by the input logic according to the current level chosen with signals Io and I1. The motor current flows through the sensing resistor RS. When the current has increased so that the voltage across RS becomes higher than the reference voltage on the other comparator input, the comparator goes high, which triggers the pulse generator. The max peak current Imax can be defined by: Vref Imax = 10 Rs Single-pulse Generator
Phase This input determines the direction of current flow
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UDN2916A
Figure 2: Principle Operating Sequence
The pulse generator is a monostable triggered on the positive going edge of the comparator output. The monostable output is high during the pulse time, toff , which is determined by the time components Rt and Ct. toff = 1.1 * RtCt The single pulse switches off the power feed to the motor winding, causing the winding current to decrease during toff. If a new trigger signal should occur during toff, it is ignored. Output Stage
The output stage contains four Darlington transistors (source drivers) four saturated transistors (sink drivers) and eight diodes, connected in two H bridge. The source transistors are used to switch the power supplied to the motor winding, thus driving a constant current through the winding. It should be noted however, that is not permitted to short circuit the outputs. Internal circuitry is added in order to increse the accuracy of the motor current particularly with low current levels. VS, VSS, VRef
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UDN2916A
The circuit will stand any order of turn-on or turnoff the supply voltages VS and VSS. Normal dV/dt values are then assumed. Preferably, VRef should be tracking VSS during power-on and power-off if VS is established. APPLICATION INFORMATIONS (Note 1) Some stepper motors are not designed for continuous operation at maximum current. As the circuit drives a constant current through the motor, its temperature might increase exceedingly both at low and high speed operation. Also, some stepper motors have such high core losses that they are not suited for switch mode current regulation. Unused inputs should be connected to proper voltage levels in order to get the highest noise immunity. As the circuit operates with switch mode current regulation, interference generation problems might arise in some applications. A good measure might then be to decouple the circuit with a 100nF capacitor, located near the package between power line and ground. The ground lead between Rs, and circuit GND should be kept as short as possible. A typical Application Circuit is shown in Fig. 3. Note that Ct must be NPO type or similar else. To sense the winding current, paralleled metal film resistors are recommended (Rs) Note 1 - Other information is available as "Smart Power Development System": HWPC2916A.
Figure 3: Typical Application Circuit.
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UDN2916A
DIP24 (20+2+2) MECHANICAL DATA
mm MIN. a1 b b1 b2 D E e F I L 3.18 7.62 2.54 6.86 4.32 0.125 0.38 0.41 0.20 1.40 0.25 1.52 0.51 0.30 1.65 30.23 0.300 0.100 0.270 0.170 TYP. MAX. MIN. 0.015 0.016 0.008 0.055 0.010 0.060 0.020 0.012 0.065 1.19 inch TYP. MAX.
DIM.
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UDN2916A
Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of SGS-THOMSON Microelectronics. (c) 1994 SGS-THOMSON Microelectronics - All Rights Reserved SGS-THOMSON Microelectronics GROUP OF COMPANIES Australia - Brazil - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco - The Netherlands - Singapore Spain - Sweden - Switzerland - Taiwan - Thaliand - United Kingdom - U.S.A.
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