June 1999
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Speed
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CA3228
Control System with Memory
Features
• Low Power Dissipation
• I
2
L Control Logic
• 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
Description
The CA3228 is a monolithic integrated circuit designed as an
automotive speed-control system.
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.
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.
The CA3228 is supplied in a 24 lead dual-in-line plastic
package (E suffix). Refer to AN7326 for application
information.
Applications
• Automotive Speed Control
• Residential and Industrial Heating and Cooling
Controls
• Industrial AC and DC Motor Speed Control
• Applications Requiring Acceleration and Deceleration
Control
Pinout
CA3228 (PDIP)
TOP VIEW
Ordering Information
PART
NUMBER
CA3228E
GND
NC
1
2
3
4
5
6
7
8
9
24 GND
23 OUTPUT GATE
22 VACUUM CONTROL
21 VENT CONTROL
20 CONTROL AMP+
19 CONTROL AMP OUTPUT
18 CONTROL AMP-
17 ALIGN
16 V ERROR
15 ACCELERATE CAPACITOR
14 ACCELERATE RESISTOR
13 V
CC
TEMPERATURE
-40
o
C to +85
o
C
PACKAGE
24 Lead Plastic DIP
DRIVER COMMAND
COMMAND DELAY
OSCILLATOR
V MEMORY
CURRENT SENSE SPEED
SENSOR INPUT
F/V OUT
F/V FILTER 10
V
S
11
BRAKE INPUT 12
CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper I.C. Handling Procedures.
Copyright
©
Harris Corporation 1999
File Number
1436.3
10-31
HARRIS [ HARRIS CORPORATION ]
