CA3228E [HARRIS]
Speed Control System with Memory; 速度控制系统的记忆
| 型号： | CA3228E |
| 厂家： | 
HARRIS CORPORATION |
| 描述： | Speed Control System with Memory |
| 文件： | 总9页 (文件大小：116K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
CA3228
Speed Control System with Memory
June 1999
Features
Description
• Low Power Dissipation
The CA3228 is a monolithic integrated circuit designed as an
automotive speed-control system.
• I2L Control Logic
The system monitors vehicle speed and compares it to a
stored reference speed. Any deviation in vehicle speed
causes a servo mechanism to open or close the engine
throttle as required to eliminate the speed error. The refer-
ence speed, set by the driver, is stored in a 9-bit counter.
• Power-On Reset
• On-Chip Oscillator for System Time Reference
• Single Input Line for Operator Commands
• Amplitude Encoded Control Signals
• Transient Compensated Input Commands
• Controlled Acceleration Mode
• Internal Redundant Brake and Low-Speed Disable
• Braking Disable
The reference speed can be altered by the ACCEL and
COAST driver commands. The ACCEL command causes
the vehicle to accelerate at a controlled rate; the COAST
command disables the servo, thereby forcing the vehicle to
slowdown. Application of the brake disables the servo and
places the system in the standby mode while the RESUME
command returns the vehicle to the last stored speed.
Vehicle speed and driver commands are inputs to the
integrated circuit via external sensors. Actuators are needed
to convert the output signals into the mechanical action
necessary to control vehicle speed.
Applications
• Automotive Speed Control
• Residential and Industrial Heating and Cooling
Controls
The CA3228 is supplied in a 24 lead dual-in-line plastic
package (E suffix). Refer to AN7326 for application
information.
• Industrial AC and DC Motor Speed Control
• Applications Requiring Acceleration and Deceleration
Control
Ordering Information
Pinout
PART
NUMBER
CA3228 (PDIP)
TOP VIEW
TEMPERATURE
PACKAGE
o
o
CA3228E
-40 C to +85 C
24 Lead Plastic DIP
1
2
24 GND
GND
NC
OUTPUT GATE
23
22
21
20
VACUUM CONTROL
VENT CONTROL
CONTROL AMP+
3
DRIVER COMMAND
COMMAND DELAY
OSCILLATOR
V MEMORY
4
5
6
19 CONTROL AMP OUTPUT
18 CONTROL AMP-
17 ALIGN
7
CURRENT SENSE SPEED
SENSOR INPUT
F/V OUT
8
9
16 V ERROR
10
11
12
15
14
13
F/V FILTER
ACCELERATE CAPACITOR
ACCELERATE RESISTOR
VCC
VS
BRAKE INPUT
CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper I.C. Handling Procedures.
File Number 1436.3
Copyright © Harris Corporation 1999
10-31
Specifications CA3228
Absolute Maximum Ratings
Thermal Information
Supply Voltage, V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +9.0V
Thermal Resistance
θ
JA
CC
o
Supply Current, I
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30mA
Plastic DIP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 C/W
Power Dissipation Per Package
CC
Driver Command Input (I
), Pin 3 . . . . . . . . . . . . . . . . . . . . 2mA
CMD
o
o
Brake Input (I
), Pin 12. . . . . . . . . . . . . . . . . . . . . . . . . . . 2mA
For T = -40 C to +70 C . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2mW
BRAKE
A
o
o
o
o
Storage Temperature Range . . . . . . . . . . . . . . . . -65 C to +150 C
Maximum Junction Temperature. . . . . . . . . . . . . . . . . . . . . +150 C
For T Above +70 C . . . . . . . . . . . Derate Linearly at 15.4mW/ C
A
o
o
Lead Temperature (Soldering 10s) . . . . . . . . . . . . . . . . . . . +265 C
Operating Temperature Range . . . . . . . . . . . . . . . . -40 C to +85 C
o
o
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation
of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
Typical Switching Characteristics
Driver Command Input Hold Times (Based on 0.68µF on Pin 4):
ACCEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50ms
ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50ms
OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50ms
COAST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50ms Internal Oscillator Frequency, F
. . . . . . . . . . . . . . . . . . . 10kHz
OSC
RESUME. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330ms
(Based on 0.001µF at Pin 5)
System Performance F
= 50kHz, f /Speed Ratio = 2.22Hz/mph
OSC
S
Speed Sensor Input Frequency Range, f at Pin 8 . .62Hz to 222Hz Maximum Stored Speed . . . . . . . . . . . . . . . . . . . . . . . . . . 100 mph
S
Speed Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.45 mph Redundant Brake Speed. . . . . . . . . . . . . . . . . . . . . . . . . . . 11 mph
Minimum Operating Speed. . . . . . . . . . . . . . . . . . . . . . . . . . 25 mph
o
Electrical Specifications T = +25 C, V = 8.20V, Unless Otherwise Specified (Refer to Figures 2 and 3)
A
CC
PARAMETERS
Operating Voltage
Speed Sensor Input Voltage Amplitude
Supply Current
SYMBOLS
TEST PIN
TEST CONDITIONS
MIN
7.40
3.50
7.50
4.85
4.00
7.6
MAX
9.00
15.0
30.0
5.95
4.20
7.9
UNITS
V
V
13
T.P.B.
13
CC
62Hz ≤ f ≤ 222Hz
Vpp
mA
V
S
V
I
CC
CC
Current Sense Voltage
Align Voltage
V
7
43kΩ to Ground
41kΩ to Ground
7
V
17
V
17
Command Idle Voltage
V
3
S1, S2, S3, S4, S5
Open
V
3IDLE
RESUME Command Voltage
ACCEL Command Voltage
COAST Command Voltage
OFF Voltage
V
3
S2 Closed
S3 Closed
S4 Closed
S5 Closed
S1 Closed
S6 Closed
5.95
3.95
1.22
0
6.56
4.91
2.23
0.77
28
V
V
V
V
V
V
3RES
V
3
3
3ACCEL
3COAST
V
V
3
3OFF
ON Voltage
V
T.P.A.
12
9.2
5.4
3ON
Brake Input Voltage
OUTPUT VOTLAGE
Gate
V
28
BRAKE
V
23
22
21
4.7kΩ to V
1.2kΩ to V
1.2kΩ to V
-
8
-
300
mV
V
OL
CC
CC
CC
V
-
400
-
OH
VAC
V
mV
V
OL
V
8
-
OH
VENT
V
400
-
mV
V
OL
V
8
OH
10-32
Specifications CA3228
o
Electrical Specifications T = +25 C, V = 8.20V, Unless Otherwise Specified (Refer to Figures 2 and 3) (Continued)
A
CC
PARAMETERS
Memory Set Error
SYMBOLS
TEST PIN
6, 10
TEST CONDITIONS
MIN
-77
MAX
67
UNITS
mV
V - V
6
10
Deadband Range (VAC and VENT Outputs
Off)
V
21, 22
Sweep Pin 19,
Voltage at 1V/sec
0.96
1.43
V
DB
Control Amplifier Gain
D/A Voltage Range
A
16, 19
6
A
= V19/V16
74
6
-
Ratio
V
CNTL
CNTL
V
Set Mode
7.50
M
Functional Block Diagram
GROUND
1
24
VCC
VCC
3
RESUME
OUTPUT
GATE
GATE
23
ACCEL
COAST
COMMAND
DECODER
AND
DRIVER COMMAND
COMMAND DELAY
3
4
I2
L
VENT
CONTROL
VENT
VAC
CONTROL
21
22
19
20
ON
OFF
DELAY
LOGIC
TOGL
VACUUM
CONTROL
CONTROL AMP.
OUTPUT
OSC.
OSCILLATOR
5
RESUME
DETECTOR
OVER SPEED
DETECTOR
+
CONTROL AMP. (+)
CONTROL AMP. (-)
V ERROR
BRAKE
SENSOR
CONTROL AMP.
BRAKE INPUT 12
18
_
ERROR AMP.
VS
REDUNDANT
BRAKE
MINIMUM
SPEED
SENSOR
16
SPEED
8
SENSOR INPUT
0.45V
“E”
F/V
ACCELERATE
RESISTOR
9
14
F/V OUT
CONVERTER
ACCEL.
RATE AMP
10
F/V FILTER
MODE
SW
“B”
“A”
ANALOG TO
DIGITAL TO
ANALOG
VS
“C”
VM
VS 11
15 ACCELERATE
CAPACITOR
“D”
CONVERTER
VM
6
V MEMORY
ALIGN
17
ALIGN
CURRENT
SENSE
CURRENT
SENSE
7
10-33
CA3228
START
NO
ERASE
MEMORY
ON
> 40 ms?
YES
YES
YES
NO
NO
NO
OFF
IGNITION
OFF?
BRAKE?
COAST?
STANDBY
RESUME?
> 40 ms?
NO
NO
NO
NO
ACCEL?
YES
YES
YES
NO
NO
ACCEL
> 4 ms?
> 25MPH?
YES
> 25MPH?
YES
YES
INPUT
> 40ms?
INPUT
> 40ms?
COAST
> 40ms?
YES
YES
NO
NO
RELAX
SERVO
> 25MPH?
YES
ACCEL AT
CONTROLLED
RATE
RELAX
SERVO
> 2 MPH?
> 25MPH
STORED?
YES
STILL
COAST?
YES
YES
STILL
ACCEL?
2
NO
NO
INPUT
> 245ms?
NO
ENABLE
SERVO
YES
YES
ENABLE
SERVO
SPEED
= STORE?
DISABLE
RESUME MODE
STORE
PRESENT
SPEED
NO
NO
SPEED
< STORE?
CRUISE
YES
ACCEL AT
CONTROLLED
RATE
YES
RELAX
SERVO
COAST
>40ms?
NO
1
YES
YES
DISABLE
ACCEL
> 40ms?
ACCEL
> 40ms?
RESUME MODE
NO
NO
NO
YES
YES
YES
YES
YES
DISABLE
IGNITION
OFF?
COAST
1
2
> 25MPH?
NO
> 40ms?
RESUME MODE
NO
BRAKE?
NO
DISABLE
Redundant
BRAKE?
RESUME MODE
NO
NO
YES
YES
YES
YES
NO
OFF
> 40ms?
CLUTCH
DISABLE?
BRAKE
NO
NO
CLUTCH
DISABLE?
10-34
CA3228
VCC
MOMENTARY
CONTACT
DRIVER
COMMAND
SWITCHES
1
24
23
22
21
20
19
18
17
16
15
14
13
T.P.A.
GATE
VAC
0.1µF
RI
560
SEE FIGURE 3
2
V3ON
10K
3
0.68µF
VENT
S1
S2
S3
4
R2
10K
ON
VCC
10K
R3, 2.2K
R4,680
5
RESUME
0.001µF
6
1M
SET/ACCEL
7
8.2K
0.05µF
43K
R5, 120
S4
S5
10K
8
COAST
OFF
0.047µF
10K
CEXT
9
2.2µF
10
11
12
2.4M
REXT
+
150K
2.2µF
10K
N
VCC
T.P.B.
S
51K
VOLTAGE AT TERM. 3
RATIO TO VCC
BRAKE LIGHT
BRAKE SWITCH
SWITCH
FUNCTION
SPEED INPUT
FREQUENCY, fS
2.22 Hz/MPH
MIN
MAX
-
S6
S1 - ON
1.12
0.725
0.482
0.148
0
S2 - RESUME
S3 - ACCEL
S4 - COAST
S5 - OFF
0.8
ALL RESISTANCE VALUES ARE IN OHMS
VBRAKE
0.599
0.272
0.094
0.96
IDLE (Note 1)
0.93
NOTE: 1. All Switches Open
FIGURE 2. TYPICAL AUTOMOTIVE SPEED CONTROL APPLICATION
0.22µF
+8.2V
VOLT.
REG
+14.4V
1.2K 1.2K
VAC
VCC
VENT
SOLENOID
VENT
VACUUM
SOLENOID
CA3228E
(SEE FIGURE 2)
TO
TO VACUUM
AIR
SOURCE
620
0.5W
4.7K
N.O.
N.C.
GATE
VENT
VALVE
VAC
VALVE
DIAPHRAGM
SYSTEM MODE
CRUISE
VALVE
ACCEL
Open
COAST
NC
VAC
NC (Note 1)
Close (Note 1)
POSITON
FEED BACK
(OPTIONAL
TO PIN 20)
VENT
NOTE:
Close
NC
1. Open or Closed as Required to Maintain Set Speed Error
TO THROTTLE
ACCEL
CRUISE
COAST
BRAKE
REDUNDANT BRAKE HI-SPEED DROPOUT LO-SPEED DROPOUT
VAC (Pin 22)
H
H
L
L
H
L
L
L
L
L
L
L
L
L
L
L
L
VENT (Pin 21)
GATE (pin 23)
H
H
H
H
FIGURE 3. SOLENOID DRIVERS AND SERVO VACUUM CONTROL MECHANISM TYPICAL APPLICATION
10-35
CA3228
FREQUENCY
Device Description and Operation
Memory Voltage, VM (Pin 6)
The functional block diagram and Figures 1, 2 show the
speed- control flow chart, and a typical automotive speed- Upon release of the ACCEL or COAST switches the voltage,
control application, respectively.
representing vehicle speed VS determined by the output
from the frequency-to-voltage converter, is stored as a
binary number in a 9 bit counter. A memory update compar-
ator allows clocking of the counter until memory voltage VM
equals VS. The output of the counter controls a ladder
network which provides memory voltage VM at pin 6.
Command Decoder and Delay Logics (Pins 3,4)
Driver commands are input to pin 3 through the Driver
Command Line. These signals are encoded on a single line
as voltage levels selected by switches which adjust a resistor
divider network.
Analog Accelerate and Resume Generator (Pins 14,15)
The voltage level established is compared to a reference
level which decodes the command. A command level greater
than VCC + 0.8V turns the system On, enabling dynamic
control. Once the system is enabled, a voltage level of
0.88VCC, 0.66VCC, and 0.38VCC decodes the RESUME,
ACCEL, and COAST command, respectively. A driver
command of 0.12VCC or less turns the system Off.
Numerous functions are combined in what is called the
Analog Accelerate and Resume Generator. The circuit
switches the signal output at pin 15 depending on the mode
of operation. In the Accelerate and Resume mode the
capacitor at pin 15 is charged at a fixed rate [450mV/(REXT
)
(CEXT)]. In the Cruise mode pin 15 follows the memory
voltage (VM) and in the On, Off, Brake, Redundant Brake,
Minimum Speed Lockout, and Coast modes, pin 15 follows
the voltage representing vehicle speed (VS).
The Driver Command Delay established by the current
sources and a capacitor at pin 4 assures that ON, OFF,
ACCEL, and COAST commands are considered valid only if
longer than 50ms. The time for RESUME is 330ms.
-40oC
Control Logic
6
+25oC
The Control Logic accepts signals from the command
decoder and other sensors. It causes the memory to be
updated when operating in ACCEL and COAST modes. It
will put the system in Standby mode if brakes are applied, if
the speed error exceeds 11mph, or if the vehicle speed
drops below the minimum Speed Lockout (25mph). It will
return the vehicle to the previous set memory speed when a
RESUME command is given.
5
+85oC
4
3
2
1
-40oC
0
0
50
100
150
200
250
Frequency to Voltage Converter (Pins 8-11)
FREQUENCY, fS (Hz)
The speed sensor input fS at pin 8 is an AC signal whose
frequency is directly proportional to the vehicle speed at
approximately 2.22Hz/mph The current sources, capacitor
and comparators at pin 9 cause equal rise and fall times to
occur at pin 9 on the positive- and negative-going slopes of
the sensor input. Pulse currents of time duration equal to the
rise and fall times are used to charge the parallel resistor
capacitor combination at pin 10 to give a voltage (VS) at pin
10 proportional to frequency at approximately 27mV/Hz. The
fS frequency range may be altered by changing the values of
the filter capacitors at pins 8 and 9. However, the maximum-
to-minimum frequency ratio will remain fixed.
FIGURE 5. TYPICAL CHARACTERISTIC F/V CONVERTER
OUTPUT, V vs FREQUENCY
S
Error Amplifier (Pin 16)
In the Cruise mode the Error Amplifier determines the
difference between the set memory speed (VM) and the
actual speed (VS). This error signal is fed to the control
amplifier where it defines whether VAC or VENT is required.
The error signal represents deviation in vehicle speed from
the memory or set speed condition. The Error signal is also
used to control the Redundant Brake feature.
Redundant Brake Comparator
-40oC
When the error output drops below approximately 0.42VCC
,
the Redundant Brake output is activated. Redundant Brake
causes the chip to go into the Standby mode.
6
+25oC
5
+85oC
Control Amplifier (Pins 18, 20)
4
The Control Amplifier is an op amp using external
components to set the gain. Inputs to the Control Amplifier
are from the Error Amplifier output, servo position sensor
and align output. The output of the Control Amplifier controls
the VAC and VENT outputs.
3
2
1
0
0
50
100
150
200
VAC, VENT and Gate-Driver Outputs (Pins 21, 22, 23)
FREQUENCY, fS (Hz)
The VAC, VENT and Gate Outputs are open collector
devices used to control the throttle position. For the system
FIGURE 4. TYPICAL D/A MEMORY VOLTAGE, V vs
M
10-36
CA3228
to be able to supply vacuum, the gate output must be low. If Activation of the RESUME switch causes a fixed accelera-
the output from the Control Amplifier exceeds 0.573VCC
,
tion rate from the lower speed until the capacitor voltage at
vacuum is supplied to the servo unit. If the output of the pin 15 is equal to the VM voltage. A filter circuit contained in
Control Amplifier is between 0.573VCC and 0.427VCC the the output of the resume comparator insures that noise
vacuum is held in the servo unit and vehicle speed is doesn’t reset the comparator until VPIN actually equals VM.
maintained. If the output from the Control Amplifier drops
below 0.427VCC or if the gate output is high, the servo unit
Align Voltage Source (Pin 17)
The Align Voltage Source is a X1 buffer with an output of
0.5VCC
vacuum is vented.
.
Overspeed Detector Comparator
Brake Input Comparator (Pin 12)
The Overspeed Detector circuit is used when the following
sequence of events occur: A speed is set in memory, the
vehicle is manually accelerated (foot pedal) to a higher
speed and then the ACCEL switch is activated.
When the Brake Input exceeds 0.55VCC, the chip will go into
the Standby mode from Cruise.
Minimum Speed Lockout
During vehicle acceleration VS voltage is greater than the VM
voltage into the memory update comparator. When the
ACCEL command is given, the capacitor at pin 15 rapidly
charges to within 60mV of VS before switching the compara-
tor output low and starting the fixed acceleration rate from
the present vehicle speed. The 60mV of offset is required to
insure that the output of the overspeed detector is low under
normal operating conditions. Hysteresis is also designed into
the comparator to eliminate noise problems which may
prevent the chip from going into the Acceleration mode.
Assures that the system remains in a Standby mode if
vehicle speed VS is below 0.183VCC. It causes the system to
revert to the Standby mode if VS drops below 0.183VCC in
the Cruise mode.
Digital Filter for Redundant Brake and Minimum Speed
Lockout
A 4 bit shift register with an all ‘1’s output decode is used to
filter transients and electromagnetic interference. The filter
prevents false signals from putting the system into Standby
from Cruise.
End of Resume Comparator
Ramp Oscillator (Pin 5)
The Resume Comparator is used when the following
sequence of events occurs: A speed is set in memory, the
brake applied, causing the vehicle to go to a lower speed,
and the RESUME switch is activated.
The Ramp Oscillator at pin 5 nominally varies between
amplitudes of 4.1V and 6.1V. The discharge rate is
approximately 4X the charge rate. With a capacitor of
0.001µF on pin 5, the nominal oscillator frequency is 50kHz.
10-37
CA3228
DVR
CMD
A
3
Q38
Q38
VCC
RESUME
+
-
ON/OFF
147
16
V’S
Q188
I17
13
12
MSLT
I113
B
C
ON ACTIVE HIGH
Q4
62
66
80
-
Q185
0.183
VCC
+
ACT HI
Q1
MIN SP
LOCKOUT
V
+
V
CC
2
Q8
67
69
79
--------- + BE
-
Q284
ACT
LO
QSC
(5)
15
18
63
Q203
ER
RESUME
Q36
I135
I136
-
Q207
+
0.43
VCC
-
Q35
10
ACT
HI
+
I58
I17
0.879
VCC
4 BIT SR
REDUNDANT
BRAKE
ENABLE
D
92
Q26
11
9
-
Q32
5
+
I25
0.661
VCC
COMMAND
DELAY
TIME GEN.
ACCEL
I146
ALL
1’S
DE-
CODE
COAST
Q31
-
8
Q30
+
I23
I21
0.376
VCC
4
ENABLE
Q8
I3
-
4
CMD
DELAY
+
Q7
V
ACCEL
COAST
CC
--------
2
2
Q26
E
65
-
Q27
+
0.121
VCC
1
OFF
F
89
ON/OFF
G
H
90
91
ACT
HI
Q141
Q136
BRK
INPUT
12
+
-
81
VCC
0.55
I142
FIGURE 6. FUNCTIONAL BLOCK DIAGRAM FOR SPEED CONTROL (Continued On Next Page)
10-38
CA3228
Q 1 7 4
FIGURE 6. FUNCTIONAL BLOCK DIAGRAM FOR SPEED CONTROL (Continued)
10-39
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