CT T ODU CEMEN 7 R P E A 74 T L OLE REP 00-442-7 OBS ENDED 8 M ns 1 .com COM pplicatio @harris E R NO ntral A entapp Ce : c Speed Call or email June 1999 CA3228 Control System with Memory Features Description • Low Power Dissipation The CA3228 is a monolithic integrated circuit designed as an automotive speed-control system. 2 • I L 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 reference 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 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. • Transient Compensated Input Commands • Controlled Acceleration Mode • Internal Redundant Brake and Low-Speed Disable • Braking Disable Applications • Automotive Speed Control • Residential and Industrial Heating and Cooling Controls • Industrial AC and DC Motor Speed Control 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 Requiring Acceleration and Deceleration Control Ordering Information Pinout CA3228 (PDIP) TOP VIEW GND 1 24 GND NC 2 23 OUTPUT GATE DRIVER COMMAND 3 22 VACUUM CONTROL COMMAND DELAY 4 21 VENT CONTROL OSCILLATOR 5 20 CONTROL AMP+ V MEMORY 6 19 CONTROL AMP OUTPUT CURRENT SENSE SPEED 7 18 CONTROL AMP- SENSOR INPUT 8 17 ALIGN F/V OUT 9 16 V ERROR F/V FILTER 10 VS 11 BRAKE INPUT 12 PART NUMBER TEMPERATURE PACKAGE CA3228E -40oC to +85oC 24 Lead Plastic DIP 15 ACCELERATE CAPACITOR 14 ACCELERATE RESISTOR 13 VCC CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper I.C. Handling Procedures. Copyright © Harris Corporation 1999 10-31 File Number 1436.3 Specifications CA3228 Absolute Maximum Ratings Thermal Information Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +9.0V Supply Current, ICC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30mA Driver Command Input (ICMD), Pin 3 . . . . . . . . . . . . . . . . . . . . 2mA Brake Input (IBRAKE), Pin 12 . . . . . . . . . . . . . . . . . . . . . . . . . . . 2mA Storage Temperature Range . . . . . . . . . . . . . . . . -65oC to +150oC Maximum Junction Temperature. . . . . . . . . . . . . . . . . . . . . +150oC Thermal Resistance θJA Plastic DIP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65oC/W Power Dissipation Per Package For TA = -40oC to +70oC . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2mW For TA Above +70oC . . . . . . . . . . . Derate Linearly at 15.4mW/oC Lead Temperature (Soldering 10s) . . . . . . . . . . . . . . . . . . . +265oC Operating Temperature Range . . . . . . . . . . . . . . . . -40oC to +85oC 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 COAST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50ms RESUME. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330ms ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50ms OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50ms Internal Oscillator Frequency, FOSC . . . . . . . . . . . . . . . . . . . 10kHz (Based on 0.001µF at Pin 5) System Performance FOSC = 50kHz, fS/Speed Ratio = 2.22Hz/mph Speed Sensor Input Frequency Range, fS at Pin 8 . .62Hz to 222Hz Speed Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.45 mph Minimum Operating Speed. . . . . . . . . . . . . . . . . . . . . . . . . . 25 mph Electrical Specifications Maximum Stored Speed . . . . . . . . . . . . . . . . . . . . . . . . . . 100 mph Redundant Brake Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 mph TA = +25oC, VCC = 8.20V, Unless Otherwise Specified (Refer to Figures 2 and 3) PARAMETERS Operating Voltage SYMBOLS TEST PIN VCC 13 Speed Sensor Input Voltage Amplitude T.P.B. TEST CONDITIONS 62Hz ≤ fS ≤ 222Hz MIN MAX UNITS 7.40 9.00 V 3.50 15.0 Vpp 7.50 30.0 mA VCC Supply Current ICC 13 Current Sense Voltage V7 7 43kΩ to Ground 4.85 5.95 V Align Voltage V17 17 41kΩ to Ground 4.00 4.20 V Command Idle Voltage V3IDLE 3 S1, S2, S3, S4, S5 Open 7.6 7.9 V RESUME Command Voltage V3RES 3 S2 Closed 5.95 6.56 V ACCEL Command Voltage V3ACCEL 3 S3 Closed 3.95 4.91 V COAST Command Voltage V3COAST 3 S4 Closed 1.22 2.23 V OFF Voltage V3OFF 3 S5 Closed 0 0.77 V ON Voltage V3ON T.P.A. S1 Closed 9.2 28 V VBRAKE 12 S6 Closed 5.4 28 V VOL 23 4.7kΩ to VCC - 300 mV 8 - V - 400 mV 8 - V - 400 mV 8 - V Brake Input Voltage OUTPUT VOTLAGE Gate VOH VAC VOL 22 1.2kΩ to VCC VOH VENT VOL 21 VOH 10-32 1.2kΩ to VCC Specifications CA3228 Electrical Specifications TA = +25oC, VCC = 8.20V, Unless Otherwise Specified (Refer to Figures 2 and 3) (Continued) PARAMETERS SYMBOLS TEST PIN V6 - V10 6, 10 VDB 21, 22 ACNTL 16, 19 VM 6 Memory Set Error Deadband Range (VAC and VENT Outputs Off) Control Amplifier Gain D/A Voltage Range TEST CONDITIONS MIN MAX UNITS -77 67 mV 0.96 1.43 V ACNTL = V19/V16 74 - Ratio Set Mode 6 7.50 V Sweep Pin 19, Voltage at 1V/sec Functional Block Diagram 1 GROUND 24 VCC VCC 3 RESUME DRIVER COMMAND COMMAND DELAY OSCILLATOR 3 4 COMMAND DECODER AND DELAY ACCEL I2 L CONTROL LOGIC COAST ON OFF TOGL GATE OUTPUT 23 GATE VENT 21 VENT CONTROL VAC VACUUM 22 CONTROL OSC. 5 19 RESUME DETECTOR OVER SPEED DETECTOR + 20 CONTROL AMP. (+) CONTROL AMP. BRAKE SENSOR BRAKE INPUT 12 CONTROL AMP. OUTPUT 18 CONTROL AMP. (-) _ ERROR AMP. SPEED SENSOR INPUT F/V OUT VS 8 9 F/V CONVERTER REDUNDANT BRAKE MINIMUM SPEED SENSOR 16 0.45V 14 ACCELERATE RESISTOR ACCEL. RATE AMP F/V FILTER 10 VS 11 V MEMORY 6 ANALOG TO DIGITAL TO ANALOG CONVERTER VS VM “C” “B” MODE SW “D” “A” 7 15 ACCELERATE CAPACITOR VM ALIGN CURRENT SENSE V ERROR “E” CURRENT SENSE 10-33 17 ALIGN CA3228 START NO ERASE MEMORY YES NO NO YES YES NO OFF > 40 ms? BRAKE? ON > 40 ms? IGNITION OFF? STANDBY NO NO NO ACCEL? COAST? YES RESUME? YES YES NO > 25MPH? ACCEL > 4 ms? > 25MPH? YES YES YES INPUT > 40ms? NO COAST > 40ms? INPUT > 40ms? NO YES YES NO ACCEL AT CONTROLLED RATE RELAX SERVO > 2 MPH? YES > 25MPH? RELAX SERVO YES > 25MPH STORED? STILL COAST? YES NO NO YES STILL ACCEL? 2 INPUT > 245ms? NO ENABLE SERVO NO YES ENABLE SERVO STORE PRESENT SPEED DISABLE RESUME MODE YES SPEED = STORE? NO NO SPEED < STORE? CRUISE YES YES ACCEL AT CONTROLLED RATE RELAX SERVO COAST >40ms? NO 1 ACCEL > 40ms? YES DISABLE RESUME MODE YES ACCEL > 40ms? NO NO NO YES YES IGNITION OFF? 1 > 25MPH? DISABLE RESUME MODE YES COAST > 40ms? 2 NO YES NO DISABLE RESUME MODE Redundant BRAKE? YES BRAKE? NO NO NO YES YES YES OFF > 40ms? BRAKE NO NO CLUTCH DISABLE? YES 10-34 CLUTCH DISABLE? NO CA3228 VCC V3ON T.P.A. R3, 2.2K R2 10K S2 RESUME 10K 0.68µF S1 ON 0.1µF RI 560 R4,680 S3 6 10 15 11 14 2.2µF 12 13 10K 51K BRAKE LIGHT BRAKE SWITCH S6 ALL RESISTANCE VALUES ARE IN OHMS SEE FIGURE 3 VAC VENT VCC 19 16 SPEED INPUT FREQUENCY, fS 2.22 Hz/MPH GATE 20 17 150K S 21 9 OFF T.P.B. 22 4 8 43K 0.047µF 0.05µF N 3 18 S4 S5 23 7 8.2K R5, 120 COAST 24 2 5 0.001µF SET/ACCEL 1 CA3228E MOMENTARY CONTACT DRIVER COMMAND SWITCHES VBRAKE 1M 10K 10K CEXT 2.2µF 10K 2.4M + REXT VCC SWITCH FUNCTION VOLTAGE AT TERM. 3 RATIO TO VCC MIN MAX S1 - ON 1.12 - S2 - RESUME 0.725 0.8 S3 - ACCEL 0.482 0.599 S4 - COAST 0.148 0.272 0 0.094 0.93 0.96 S5 - OFF IDLE (Note 1) NOTE: 1. All Switches Open FIGURE 2. TYPICAL AUTOMOTIVE SPEED CONTROL APPLICATION 0.22µF +8.2V 1.2K VOLT. REG +14.4V 1.2K VCC VAC VENT SOLENOID VENT VACUUM SOLENOID CA3228E (SEE FIGURE 2) TO 620 0.5W 4.7K GATE TO VACUUM AIR SOURCE N.O. N.C. VENT VALVE VAC VALVE DIAPHRAGM SYSTEM MODE VALVE POSITON FEED BACK (OPTIONAL TO PIN 20) ACCEL CRUISE VAC Open NC (Note 1) COAST NC VENT Close Close (Note 1) NC NOTE: 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 L L L L L L VENT (Pin 21) H H L L L L L GATE (pin 23) L L L H H H H FIGURE 3. SOLENOID DRIVERS AND SERVO VACUUM CONTROL MECHANISM TYPICAL APPLICATION 10-35 CA3228 Device Description and Operation FREQUENCY 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. 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. 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. Memory Voltage, VM (Pin 6) Upon release of the ACCEL or COAST switches the voltage, 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 comparator 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. Analog Accelerate and Resume Generator (Pins 14,15) 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). MEMORY VOLTAGE, VM (V) The functional block diagram and Figures 1, 2 show the speed- control flow chart, and a typical automotive speedcontrol application, respectively. Control Logic 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. 6 +25oC 5 +85oC 4 3 2 1 0 Frequency to Voltage Converter (Pins 8-11) 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 maximumto-minimum frequency ratio will remain fixed. -40oC -40oC 0 50 100 150 FREQUENCY, fS (Hz) 200 250 FIGURE 5. TYPICAL CHARACTERISTIC F/V CONVERTER OUTPUT, VS vs FREQUENCY 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. MEMORY VOLTAGE, VM (V) Redundant Brake Comparator -40oC 6 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. +25oC 5 +85oC 4 3 2 1 0 0 50 100 150 200 FREQUENCY, fS (Hz) FIGURE 4. TYPICAL D/A MEMORY VOLTAGE, VM vs Control Amplifier (Pins 18, 20) 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. VAC, VENT and Gate-Driver Outputs (Pins 21, 22, 23) The VAC, VENT and Gate Outputs are open collector devices used to control the throttle position. For the system 10-36 CA3228 to be able to supply vacuum, the gate output must be low. If the output from the Control Amplifier exceeds 0.573VCC, vacuum is supplied to the servo unit. If the output of the Control Amplifier is between 0.573VCC and 0.427VCC the vacuum is held in the servo unit and vehicle speed is maintained. If the output from the Control Amplifier drops below 0.427VCC or if the gate output is high, the servo unit vacuum is vented. Overspeed Detector Comparator 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. 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 comparator 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. End of Resume Comparator 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. Activation of the RESUME switch causes a fixed acceleration rate from the lower speed until the capacitor voltage at pin 15 is equal to the VM voltage. A filter circuit contained in the output of the resume comparator insures that noise doesn’t reset the comparator until VPIN actually equals VM. Align Voltage Source (Pin 17) The Align Voltage Source is a X1 buffer with an output of 0.5VCC. Brake Input Comparator (Pin 12) When the Brake Input exceeds 0.55VCC, the chip will go into the Standby mode from Cruise. Minimum Speed Lockout 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. Ramp Oscillator (Pin 5) 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 Q38 Q38 +- VCC A RESUME ON/OFF 147 I17 13 ON ACTIVE HIGH Q4 12 16 V’S Q188 V CC 2 Q8 + V BE - Q284 79 15 RESUME Q36 Q35 + I17 0.879 VCC 62 Q185 + ACT HI 0.183 VCC MIN SP LOCKOUT Q1 ---------- + MSLT I113 - ER 18 0.43 VCC 10 ACT Q203 LO - Q207 + ACT HI REDUNDANT BRAKE ENABLE Q26 Q32 + I25 0.661 VCC ACCEL Q31 COAST Q30 + I23 0.376 VCC ENABLE 5 9 66 67 C QSC 63 (5) 69 I135 I136 I58 4 BIT SR D 92 11 COMMAND DELAY TIME GEN. I146 ALL 1’S DECODE 8 4 Q8 CMD 4 DELAY Q26 Q27 + I21 0.121 OFF VCC B 80 I42 I35 I50 I51 3 V CC -------2 - Q7 + I3 ACCEL 2 E 65 COAST 1 F 89 ON/OFF G 90 BRK INPUT 12 0.55 VCC Q141 Q136 + - 91 ACT HI 81 I142 FIGURE 6. FUNCTIONAL BLOCK DIAGRAM FOR SPEED CONTROL (Continued On Next Page) 10-38 H 10-39 FIGURE 6. FUNCTIONAL BLOCK DIAGRAM FOR SPEED CONTROL (Continued) SENSOR INPUT H G E F D C B A 8 I128 AMPL AND LIMITER Q98 97 103 93 94 68 AC + MSLT OSC (4) 84 I125 2I F/V 96 101 102 95 Q D Q OSC (3) 117 118 123 122 119 OSC (2) 120 9 98 Q225 Q228 Q105 0.012 Q110 VCC Q125 0.482 Q114 VCC Q113 I + Q156 Q166 0.427 Q167 VCC + VCC 0.573 Q168 VCC Q171 Q161 RESUME COMP Q216 + - - COMP “A” Q232 85 21 I/2 Q242 Q212 10 Q117 Q118 Q112 + 15 BUF + 60MV - Q122 11 VS Q270 Q258 Q271 - 450MV 113 VS S 2 CC --------- V + 16 V ERROR Q200 ER + X1 ACTIVE ACCEL CLAMP Q196 ERROR AMP Q201 112 111 72 BUFFER AND LEVEL SHIFT Q269 AC + MSLT 71 OSC (3) Q276 ACCEL 14 RESISTOR 70 VBE VCC /2 + I141 ACTIVE LOW MEM UPDATE + - BUFFER AND LEVEL SHIFT Q277 V’S BUF Q279 Q278 Q268 110 XI 20 CONTROL AMP (+) Q277 Q119 15 + ACCEL CAP. “D” Q251 Q257 109 CONTROL 18 AMP (-) Q121 X1 Q178 + 87 88 CONTROL AMP Q177 + 19 CONTROL AMP OUTPUT Q179 I138 + OVER SPEED DET. Q213 ACTIVE HIGH Q276 75, 76, 77 108 OPEN DURING ACC, RES RAMP + XI 104 ON/OFF VM 107 F/V FILTER Q111 ACT LO 23 ACT LO GATE 86 AC + MSLT 106 105 ACT HI VENT 22 VAC Q231“B” COMP AND CLAMP + + Q157 + - + ACTIVE LOW + TO B IN ON, OFF, BRAKE, COAST VSS A/D Q174 100 OPEN POSITION DURING SET ACCEL AND RESUME 99 + TO A IN CRUISE ACTIVE LOW OSC (3) I145 I121 Q174 BUF 17 ALIGN 115 114 1 7 6 24 GND CURRENT SENSE 13 VCC A/D Q9 D/A CLOCK OSC OSC D/A CLOCK 9 BIT D/A 73 DC BIAS VM Q1 5 OSC D/A CLEAR OSC (1) A/D CA3228