CHERRY CS3717AGNF16

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
Features
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
CS3717AÕs and several external
components form a complete stepper motor drive subsystem.
The recommended operating ambient temperature range is from 0 to
70¡C.
The CS3717A is supplied in a 16
lead PDIP.
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 .................................................................Ð55¡C to +150¡C
Operating Junction Temperature.............................................Ð40¡C to +150¡C
Lead Temperature Soldering
Wave Solder(through hole styles only) ............10 sec. max, 260¡C peak
Block Diagram
IN1
IN0
DIRECTION
00
6KW
01
10
Package Options
16L PDIP
(Internally Fused Leads)
OUTB
VDDA OUTA OUTB VDDB
VCC
VREF
■ Full/Half /Quarter Step
Operation
■ Output Current Up to 1 A
■ Motor Supply Voltage 10V
to 46V
■ Integrated Bootstrap
Lowers Saturation Voltage
■ Built In Protection Diodes
■ Externally Selectable
Current Level
■ Digital or Analog Control
of Output Current Level
■ Thermal Overload
Protection
■ Minimum External
Components
Sense
1
Pulse
OUTA
VDDB
VDD
Gnd
Gnd
Gnd
Gnd
11
+
-
VCC
VREF
IN1
Comp In
DIRECTION
223W
A
IN0
+
-
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: [email protected]
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 = 25¡C; unless otherwise specified.
PARAMETER
Supply Voltage
Logic Supply Voltage
Logic Supply Current
Reference Input Current
TEST CONDITIONS
MIN
TYP
MAX
UNIT
7
0.75
46
5.25
15
1.00
V
V
mA
mA
0.8
V
(DIRECTION)
-100
V
µA
(IN0, IN1)
-400
10
µA
µA
10
4.75
VREF = 5V
■ Logic Inputs
Input Low Voltage
Input High Voltage
Low Voltage Input Current
VIN = 0.4V
2
High Voltage Input Current
VIN = 2.4V
■ Comparators
Comparator Low
Threshold Voltage
Comparator Medium
Threshold Voltage
Comparator High
Threshold Voltage
Comparator Input Current
Cutoff Time
Turn Off Delay
Output Leakage Current
VREF = 5V
VREF = 5V
VREF = 5V
RT = 56k½
IN0 = Low
IN1 = High
IN0 = High
IN1 = Low
IN0 = Low
IN1 = Low
CT = 820pF
66
80
94
mV
236
251
266
mV
396
416
436
mV
±20
37
µA
µs
2
100
µs
µA
27
IN0 =IN1 = High
■ Source Diode-Transistor Pair
Saturation Voltage
IMOTOR = -0.5A conduction period
recirculation period
IMOTOR = -1A conduction period
recirculation period
VS = 46V
1.7
1.10
2.1
1.7
2.1
1.35
2.8
2.5
300
V
V
V
V
µA
IMOTOR = -0.5A
IMOTOR = -1A
1.00
1.3
1.25
1.7
V
V
Saturation Voltage
IMOTOR = 0.5A
IMOTOR = 1A
1.20
1.75
1.45
2.30
V
V
Leakage Current
VS = 46V
300
µA
Diode Forward Voltage
IMOTOR = 0.5A
IMOTOR = 1A
1.5
2.0
V
V
Saturation Voltage
Leakage Current
Diode Forward Voltage
■ Sink Diode-Transistor Pair
1.1
1.4
2
IN0
IN1
Output Current
H
H
No Current
L
H
Low Current
H
L
Medium Current
L
L
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 ÒHÓ bridge
formed by four transistors and four diodes suitable for switching
applications.
2
Pulse
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).
3
VDDB
Supply voltage input for half output stage.
4, 5, 12, 13
Gnd
Ground connection. Also conducts heat from die to printed
circuit copper.
6
VCC
Supply voltage input for logic circuitry.
7
IN1
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.
8
DIRECTION
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.
9
IN0
10
Comp In
11
VREF
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).
14
VDDA
Supply voltage input for half output stage.
15
OUT A
16
Sense
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.
See OUTB.
Connection to lower emitters of output stage for insertion of
current sense resistor.
3
CS3717A
Truth Table
CS3717A
Typical Performance Characteristics
Source Saturation Voltage vs. Output Current
(Conduction Period)
4
4
3
3
VCE SAT (V)
VCE SAT (V)
Source Saturation Voltage vs. Output Current
(Recirculation Period)
2
1
2
1
0
0.2
0.4
0.6
0
0.8
0.2
0.4
0.6
0.8
I (A)
I (A)
Sink Saturation Voltage vs. Output Current
Comparator Threshold vs. Junction Temperature
3
100
2
VCX (%)
VSAT (V)
4
1
80
60
40
20
0
0
0.2
0.4
0.6
0.8
20 40 60 80 100 120 140 160
TJ (C)
I (A)
Application Information
The application diagram shows a typical application in
which two CS3717A's control a two phase bipolar stepper
motor.
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.
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 ÒDirectionÓ 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.
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®AB®AB®AB etc.
4
For rotation in the other direction the sequence must be
reversed.
The extra quarter steps are added to the half step
sequence by putting one coil on half current according to
the sequence.
AB®AB®B®AB®AB®AB®A etc.
2
2
2
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:
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.
AB®B®AB®A®AB®B®AB®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.
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.
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.
Input and Output Sequences for Half Step and Full Step Operation
L
OUTA
CS3717A
MOTOR
WINDING
(LM, RM)
C
OUTB
[email protected]
1 L
M
10
STAND BY WITH
HOLDING TORQUE
1M = 80mA
[email protected]
HALF STEP MOTOR DRIVE
1M = 250mA
1
2
3
4
5
6
IN0A
IN1A
IN
DIRECTIONA
DIRECTIONB
IN0B
IN1B
500 mA
IMA
OUT
- 500 mA
500 mA
IMB
- 500 mA
5
7
8
4 ¥ 1010
L
FULL STEP MOTOR DRIVE
1M = 500mA
CS3717A
Application Information: continued
CS3717A
Test Circuit
Reference
Voltage
+5V
IN1
Logic
Control
Inputs
Logic
Supply
+5V
VREF
Motor
Supply
+36V
VCC
VDDB
VDDA
L @ 10mH
R @ 13W
OUTA
CS3717A
IN0
DIRECTION
Pulse
Gnd
OUTB
Comp In Sense
VC
CT
CC
RT
820 pF
820 pF
56kW
Motor
Winding
L
RC
1kW
VRS
RSENSE
1W
Gnd
Waveforms with MA Regulating (Phase = 0)
VCX
VSENSE
0V
VCX
t
TD
VComp In
0V
t
VDD
VOUT A
VF
VSAT
0V
VSAT REC
VCC
VOUT B
VMOTOR
t
VSAT COND
TON
TOFF
t
0V
6
CS3717A
Application Circuit - Two Phase Bipolar Stepper Motor Driver
VSS
0.1mF C3
VS
C1 100mF
C2
0.1mF
VREF
IN1
VDD
VDD
VCC
MAA
A
B
OUTA
CS3717A
CS-3717A
IN0
DIRECTION
Gnd
Pulse
Gnd
MBA
OUTB
Sense
COMP IN
RC
1kW
CT
RT
FROM
m PROCESSOR
CC
820pF
56kW
CT
RT
CC
820pF
56kW
1W
RSense
820pF
IMA
1W
RSense
820pF
RC
IMB
1kW
Pulse
Gnd
Gnd
Out B
DIRECTION
CS3717A
IN1
IN0
VREF
STEPPER
MOTOR
Sense
Comp In
VDD
VCC
OutA
VDD
B
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 Òl Ó of
two equal square copper areas having a thickness of 35µ
(see fig. 1). In addition, it is possible to use an external
heatsink (see fig. 3). During soldering the pins temperature
must not exceed 260ûC 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)
COPPER AREA 35m THICKNESS
Rq JA
(ûC/W)
80
4
Rq JA
3
l
60
40
2
Ptot (Tamb = 70ûC)
1
20
l
0
P.C. BOARD
0
10
20
30
0
I(mm)
40
ÒlÓ
Figure 1 - Example of P.C. Board Copper Area Which is Used as
Heatsink with 16 lead fused package.
Figure 2 - Max. Power Dissipation And Junction To Ambient Thermal
Resistance vs. Size ÒlÓ for 16 lead fused package.
Ptot
(W)
170mm
HE
AT
-
IN
4
TH
WI
5
FIN
SIN
ITH
R
th =
Figure 3 - External Heatsink Mounting Example (Rth = 30ûC/W) for 16
lead batwing package.
0
50
100
K
E AIR
1
0
-50
/W
FRE
SIN
38.0mm
25
ûC
2
AT
HE
11.9mm
ITE
KW
3
Tamb (C)
Figure 4 - Maximum Allowable Power Dissipation vs. Ambient
Temperature for 16 lead batwing package.
7
CS3717A
Package Specification
PACKAGE THERMAL DATA
PACKAGE DIMENSIONS IN mm (INCHES)
D
Lead Count
16L PDIP
(Internally Fused Leads)
Metric
Max
Min
19.69
18.67
16 Lead PDIP
Thermal Data
RQJC
typ
RQJA
typ
English
Max Min
.775
.735
(Internally Fused Leads)
15
50
ûC/W
ûC/W
Plastic DIP (N); 300 mil wide
7.11 (.280)
6.10 (.240)
8.26 (.325)
7.62 (.300)
1.77 (.070)
1.14 (.045)
2.54 (.100) BSC
3.68 (.145)
2.92 (.115)
.356 (.014)
.203 (.008)
0.39 (.015)
MIN.
.558 (.022)
.356 (.014)
REF: JEDEC MS-001
D
Some 8 and 16 lead
packages may have
1/2 lead at the end
of the package.
All specs are the same.
Ordering Information
Part Number
CS3717AGNF16
Rev. 4/29/99
Description
16 Lead PDIP
(Internally Fused Leads)
Cherry Semiconductor Corporation reserves the
right to make changes to the specifications without
notice. Please contact Cherry Semiconductor
Corporation for the latest available information.
8
© 1999 Cherry Semiconductor Corporation