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