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CS3717A
CS3717A
1A H-Bridge Stepper Motor Driver
Description
The CS3717A controls and drives one phase of a bipolar stepper motor with chopper control of the phase current. Current levels may be selected in three steps by means of two logic inputs which select one of three current comparators. When both of these inputs are high the device is disabled. A separate logic input controls the direction of current flow. A monostable, programmed by an external RC network, sets the current decay time. The power section is a full H-bridge driver with four internal clamp diodes for current recirculation. An external connection to the lower emitters is available for the insertion of a sensing resistor. Two CS3717AOs and several external components form a complete stepper motor drive subsystem. The recommended operating ambient temperature range is from 0 to 70C. The CS3717A is supplied in a 16 lead PDIP.
Features
s Full/Half /Quarter Step Operation s Output Current Up to 1 A s Motor Supply Voltage 10V to 46V s Integrated Bootstrap Lowers Saturation Voltage s Built In Protection Diodes s Externally Selectable Current Level s Digital or Analog Control of Output Current Level s Thermal Overload Protection s Minimum External Components
Absolute Maximum Ratings Power Supply Voltage (VDDA, VDDB) ............................................................50V Logic Supply Voltage (VCC)..............................................................................7V Logic Input Voltage (IN0, IN1, DIRECTION)................................................6V Comparator Input............................................................................................VCC Reference Input Voltage..................................................................................15V Output Current (DC Operation)...................................................................1.2A Storage Temperature .................................................................55C to +150C Operating Junction Temperature.............................................40C to +150C Lead Temperature Soldering Wave Solder(through hole styles only) ............10 sec. max, 260C peak Block Diagram
IN0 IN1 DIRECTION VDDA OUTA OUTB VDDB
Package Options
16L PDIP
(Internally Fused Leads)
OUTB Pulse VDDB
1
Sense OUTA VDD
A
VCC
Gnd Gnd
00 6KW 01 10 11
Gnd Gnd VREF Comp In IN0
VREF + 223W
VCC IN1 DIRECTION
+ 223W
+ -
MONOSTABLE
105W THERMAL SHUTDOWN
Gnd
Comp In
Pulse
Sense
Cherry Semiconductor Corporation 2000 South County Trail, East Greenwich, RI 02818 Tel: (401)885-3600 Fax: (401)885-5786 Email: info@cherry-semi.com Web Site: www.cherry-semi.com
Rev. 4/29/99
1
A
Company
CS3717A
Electrical Characteristics: Refer to the test circuit VDD = 36V, VCC = 5V, TA = 25C; unless otherwise specified.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Supply Voltage Logic Supply Voltage Logic Supply Current Reference Input Current s Logic Inputs Input Low Voltage Input High Voltage Low Voltage Input Current High Voltage Input Current s Comparators Comparator Low Threshold Voltage Comparator Medium Threshold Voltage Comparator High Threshold Voltage Comparator Input Current Cutoff Time Turn Off Delay Output Leakage Current s Source Diode-Transistor Pair Saturation Voltage Saturation Voltage Leakage Current Diode Forward Voltage
10 4.75 VREF = 5V 7 0.75
46 5.25 15 1.00
V V mA mA
0.8 2 VIN = 0.4V VIN = 2.4V (DIRECTION) (IN0, IN1) -100 -400 10
V V A A A
VREF = 5V VREF = 5V VREF = 5V
IN0 = Low IN1 = High IN0 = High IN1 = Low IN0 = Low IN1 = Low CT = 820pF
66 236 396
80 251 416
94 266 436 20 37 2 100
mV mV mV A s s A
RT = 56k1/2
27
IN0 =IN1 = High
IMOTOR = -0.5A conduction period recirculation period IMOTOR = -1A conduction period recirculation period VS = 46V IMOTOR = -0.5A IMOTOR = -1A
1.7 1.10 2.1 1.7 1.00 1.3
2.1 1.35 2.8 2.5 300 1.25 1.7
V V V V A V V
s Sink Diode-Transistor Pair Saturation Voltage Leakage Current Diode Forward Voltage IMOTOR = 0.5A IMOTOR = 1A VS = 46V IMOTOR = 0.5A IMOTOR = 1A 1.1 1.4 1.20 1.75 1.45 2.30 300 1.5 2.0 V V A V V
2
CS3717A
Truth Table
IN0 IN1 Output Current
H L H L
H H L L
No Current Low Current Medium Current High Current
Package Pin Description
PACKAGE PIN # PIN SYMBOL FUNCTION
16L
(Internally Fused Leads)
1
OUT B
Output connection with OUTA. The output stage is a OHO bridge formed by four transistors and four diodes suitable for switching applications. A parallel RC network connected to this pin sets the OFF time of the lower power transistors. The pulse generator is a monostable triggered by the rising edge of the output of the comparators (tOFF = 0.69 RTCT). Supply voltage input for half output stage. Ground connection. Also conducts heat from die to printed circuit copper. Supply voltage input for logic circuitry. This pin and IN0 are logic inputs which select the outputs of the three comparators to set the current level. Current also depends on the sensing resistor and reference voltage. See truth table. This TTL-compatible logic input sets the direction of current flow through the load. A high level causes current to flow from OUTA (source) to OUTB (sink). A Schmitt trigger on this input provides good noise immunity and a delay circuit prevents output stage short circuits during switching. See IN1. Input connected to the three comparators. The voltage across the sense resistor is fed back to this input through the low pass filter RCCC. The lower 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 RTCT, tOFF = 0.69 RTCT. A voltage applied to this pin sets the reference voltage of the three comparators, thus determining the output current (also dependent on RSense and the two inputs IN 0 and IN 1). Supply voltage input for half output stage. See OUTB. Connection to lower emitters of output stage for insertion of current sense resistor.
2
Pulse
3 4, 5, 12, 13 6 7
VDDB Gnd VCC IN1
8
DIRECTION
9 10
IN0 Comp In
11
VREF
14 15 16
VDDA OUT A Sense
3
CS3717A
Typical Performance Characteristics
Source Saturation Voltage vs. Output Current (Recirculation Period) Source Saturation Voltage vs. Output Current (Conduction Period)
4
4
VCE SAT (V)
2
VCE SAT (V) 0.2 0.4 I (A) 0.6 0.8
3
3
2
1
1
0
0 0.2 0.4 I (A) Comparator Threshold vs. Junction Temperature 0.6 0.8
Sink Saturation Voltage vs. Output Current
4
VSAT (V)
3 100 VCX (%) 2 80 60 40 20 0 0 0.2 0.4 I (A) 0.6 0.8 20 40 60 80 100 120 140 160 TJ (C)
1
Application Information The application diagram shows a typical application in which two CS3717A's control a two phase bipolar stepper motor. Programming The amplitude of the current flowing in the motor winding is controlled by the logic inputs IN0 and IN1. The truth table (page 3) shows three current levels and an off state. A high level on the ODirectionO logic input sets the direction of that current from OUTA to OUTB; a low level from OUTB to OUTA. It is recommended that unused inputs are tied to VCC or (Gnd) as appropriate to avoid noise problems. The current levels can be varied continuously by changing VREF. Control of the motor The stepper motor can rotate in either direction according to the sequence of the input signals. It is possible to obtain a full step, a half step and quarter step operation. Full step operation Both windings of the stepper motor are energized all the time with the same current IMA = IMB. IN0 and IN1 remain fixed at whatever torque value is required. Calling A the condition with winding A energized in one direction and A in the other direction, the sequence for full step rotation is: AB(R)AB(R)AB(R)AB etc.
4
CS3717A
Application Information: continued For rotation in the other direction the sequence must be reversed. The torque of each step is constant in full step operation. Half step operation Power is applied alternately to one winding then both according to the sequence: AB(R)B(R)AB(R)A(R)AB(R)B(R)AB(R)A etc. Like full step this can be done at any current level; the torque is not constant but is lower when only one winding is energized. A coil is turned off by setting IN0 and IN1 both high. Quarter step operation It is preferable to realize the quarter step operation at full power otherwise the steps will be of very irregular size. The extra quarter steps are added to the half step sequence by putting one coil on half current according to the sequence. AB(R)AB(R)B(R)AB(R)AB(R)AB(R)A etc. 2 2 2 Motor selection As the CS3717A provides constant current drive with a switching operation, care must be taken to select stepper motors with low hysteresis losses to prevent motor overheating. L-C filter To reduce EMI and chopping losses in the motor, a low pass L-C filter can be inserted across the outputs of the CS3717A as shown in the following diagram.
Input and Output Sequences for Half Step and Full Step Operation
L OUTA CS3717A OUTB L@ 1L M 10 C@ C MOTOR WINDING (LM, RM)
4 1010 L
STAND BY WITH HOLDING TORQUE 1M = 80mA
1
HALF STEP MOTOR DRIVE 1M = 250mA
2 3 4 5 6 7 8
FULL STEP MOTOR DRIVE 1M = 500mA
IN0A IN1A
IN
DIRECTIONA DIRECTIONB
IN0B IN1B
500 mA
IMA - 500 mA 500 mA IMB
OUT
- 500 mA
5
CS3717A
Test Circuit
Reference Voltage +5V
Logic Supply +5V
Motor Supply +36V
IN1 Logic Control Inputs
VREF
VCC
VDDA
VDDB OUTA
L @ 10mH R @ 13W L Motor Winding
IN0
CS3717A
OUTB Comp In Sense VC RC 1kW VRS
DIRECTION Pulse
Gnd
CT 820 pF Gnd
RT 56kW
CC 820 pF
RSENSE 1W
Waveforms with MA Regulating (Phase = 0)
VCX VSENSE 0V VCX VComp In 0V VDD VOUT A 0V VSAT REC VCC VOUT B VSAT COND VSAT VF TD
t
t
t
VMOTOR 0V
TON
TOFF t
6
CS3717A
Application Circuit - Two Phase Bipolar Stepper Motor Driver
0.1mF C3 VSS VS C1 100mF C2 0.1mF
VREF IN1 IN0 DIRECTION Gnd Pulse VCC VDD
B
VDD
A
OUTA
MAA MBA
CS3717A CS-3717A
Gnd COMP IN OUTB Sense
RC 1kW RT FROM m PROCESSOR 56kW RT 56kW CT 820pF CT 820pF CC 820pF CC 820pF RC 1kW
Pulse DIRECTION IN1 IN0 VREF Gnd Gnd Comp In Sense Out B
1W RSense 1W RSense
IMA
IMB STEPPER MOTOR
CS3717A
VCC VDD
B
OutA VDD
A
Mounting Instructions The RQJA of the CS3717A can be reduced by soldering the Gnd pins to a suitable copper area of the printed circuit board or to an external heatsink. The diagram of fig. 2 shows the maximum dissipated power Ptot and the RQJA as a function of the side Ol O of two equal square copper areas having a thickness of 35 (see fig. 1). In addition, it is possible to use an external heatsink (see fig. 3). During soldering the pins temperature must not exceed 260uC and the soldering time must not be longer than 12 seconds. The external heatsink or printed circuit copper area must be connected to electrical ground.
Ptot (W) 4 3 l 2 1 l 0 P.C. BOARD 0 10 20 OlO 30 40 0 I(mm) Ptot (Tamb = 70uC) Rq JA Rq JA (uC/W) 80 60 40 20
COPPER AREA 35m THICKNESS
Figure 1 - Example of P.C. Board Copper Area Which is Used as Heatsink with 16 lead fused package.
170mm
Figure 2 - Max. Power Dissipation And Junction To Ambient Thermal Resistance vs. Size OlO for 16 lead fused package.
Ptot (W) 5 4 3
HE AT SIN
TH WI IN FIN
KW
ITH
ITE
11.9mm 38.0mm
R
th =
AT HE
2 1 0 -50 0 50
25
uC
/W
SIN
FRE
E AIR
K
100
Tamb (C)
Figure 3 - External Heatsink Mounting Example (Rth = 30uC/W) for 16 lead batwing package.
Figure 4 - Maximum Allowable Power Dissipation vs. Ambient Temperature for 16 lead batwing package.
7
CS3717A
Package Specification
PACKAGE DIMENSIONS IN mm (INCHES) PACKAGE THERMAL DATA
D Lead Count 16L PDIP (Internally Fused Leads) Metric Max Min 19.69 18.67 English Max Min .775 .735 Thermal Data RQJC typ RQJA typ
16 Lead PDIP
(Internally Fused Leads)
15 50
uC/W uC/W
Plastic DIP (N); 300 mil wide
7.11 (.280) 6.10 (.240)
8.26 (.325) 7.62 (.300) 3.68 (.145) 2.92 (.115)
1.77 (.070) 1.14 (.045)
2.54 (.100) BSC
.356 (.014) .203 (.008)
0.39 (.015) MIN. .558 (.022) .356 (.014) Some 8 and 16 lead packages may have 1/2 lead at the end of the package. All specs are the same.
REF: JEDEC MS-001
D
Ordering Information
Part Number CS3717AGNF16
Description 16 Lead PDIP (Internally Fused Leads) 8
Cherry Semiconductor Corporation reserves the right to make changes to the specifications without notice. Please contact Cherry Semiconductor Corporation for the latest available information.
(c) 1999 Cherry Semiconductor Corporation
Rev. 4/29/99

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