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MOTOROLA
SEMICONDUCTOR
TECHNICAL DATA
MC33187
LONG DURATION AUTOMOTIVE TIMER
SILICON MONOLITHIC INTEGRATED CIRCUIT
Prototype Information
Long Duration Automotive Timer
This circuit is a Long Duration Automotive Timer primarily designed as a deffoger timer, but as it is realised using a digital divider techniques and it is suitable for a variety of long duration timing functions. The circuit is available in an 8 pin DIL plastic as well as in an 8 pin surface mount package. Operating Ambient Temperature from -40C to 85C Operating Voltage Range from 5V to 18V 400mA Output Current Capability Integrated Input Debounce Circuitry Few External Components Toggle Input for Timing Start and Stop
PIN ASSIGNMENT
RC 1 Gnd 2 Relay
3 8 7 6 5
TS N/C N/C Vcc3
Toggle 4
ORDERING INFORMATION Temperature Device Package Range -40C to +85C SO8 MC33187D MC33187P -40C to +85C DIL8
Block Diagram and Typical Application
Vbat
C C S Q Q C R
Q
C C 6.8 Hz S
Q Q
R-C 1
Q
12
Q
1
Q
C S
Vbat
Q
Q
S1
Q D R C
J
S
Q
Dz
Relay 3
Q Q
14
13
R R
8 TS
Debounce Timer
Out Timing In
I
+
5
5
VCC
2
+
2.3V
4
Toggle
This document contains information on a new product under development. Motorola reserves the O Motorola,Inc right to change or discontinue this product without notice.
Date : 10/12/98 Rev 2.0
MC33187
MAXIMUM RATINGS
Ratings ELECTRICAL RATINGS Symbol Value Unit
Pin 5 voltage Pin 3 Voltage Pin 3 Current
THERMAL RATINGS
Vpin5 Vpin3 Ipin3
18 18 400
V V mA
Storage Temperature Operating Junction Temperature
Tstg Tj
-55 to +175 -40 to +150
C C
ELECTRICAL CHARACTERISTICS. Tamb from - 40C to + 85C, Vcc = 14V through 1KW, unless otherwise noted. Typical values reect approximate
mean at 25C, nominal VCC, at time of device characterization.
Parameters RC PIN 1
Symbol
Min
Typ
Max
Unit
Oscillator Frequency Vbat = 14V trough 1KW Internal Counter Divider step
RELAY PIN 3
fo VR1
300 4096
400
Hz
Output Leakage current @ Vpin3 = 28V / Vbat =14V Output Leakage current @ Vpin3 = 22V / Vbat = 0V Output Saturation Voltage @ 250mA / Vbat = 14V Output Saturation Voltage @ 400mA
TOGGLE PIN 4
IO1 IO2 VO1 VO2
100 100 1.35 2.60
uA uA V V
Toggle Input Clamp @ Vbat = 14V / Vpin8 = 14V through 9.1KW Toggle Threshold
VCC3 PIN 5
TCLP VTG-T
6.0 1.0
9.0 4.0
V V
Supply Current @ Vcc = 5V VCC Zener Regulation @ Vbat = 14V through 1K
TS PIN 8
ICC VCC
0.5 6.0
3.5 8.0
mA V
Time Select Current @ TS = 5V
ITS
25
200
uA
MC33187
MOTOROLA
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MC33187
DEVICE DESCRIPTION Pin 1 : RC Oscillator frequency control. Rt and Ct control the frequency of the clock oscillator. The period of oscillation is nominally given by t = RtCt with the overall time period given by T = 4096 RtCt. However, the following formula is believed to give a more accurate forecast of the overall time interval provided by the circuit for values of Rt between 200K and 2M and values of Ct between 1nF and 1uF. Formula : T = 4.1 10e-3 (RT * (RT/150)*2.7) *CT. Pin 2 : GND Ground : Most negative supply terminal. Pin 3 : RELAY Relay output driver. Open collector drive from a Darlington transistor rated. Icmax = 400mA and Vmax = 18V. The relay driver output is on (low) during the time period. APPLICATION This is the standard operation of this circuit requiring the minimum of extra components. The ON/OFF switch is a non-latching push button (or similar), illuminated by a lamp in parallel with the rear window defogger. Rin protects the toggle input from supply line transients with a nominal of Rin = 10KW. The relay is intended to be a standard automotive relay (Rnom = 60W) with contacts rated appropriately for the defogger controlled. Dz with a nominal value of 16V +-5% is included to provide protection of the relay drive output transistor against relay turn-off and supply lines transients. The type of zener used is dependent of the level of protection required. An MZD16 will provide adequate protection for all relay turn-off and low energy supply transients, while a P6KE16A will provide full protection against all known transients. If the relay output is to be connected in any other way or to a non-standard relay, the maximum ratings quoted under the General Description above should be noted. Pin 4 : TOGGLE On/Off Control. A positive going voltage transition on this input toggles the timer between the On and Off state. If the timer is On and timing, it may be turned off by a positive going signal on the toggle pin before the time delay has elapsed. Pin 5 : VCC Positive supply terminal. The timer requires a supply voltage of 5 to 18V applied to Vcc through Rs. An internal 7V zener limits the Vcc terminal voltage. Cs is included to provide supply rail decoupling. Recommended values of Rs and Cs on a standard 12V vehicle system are Rs = 1KOhm and Cs = 100nF.
Figure 1. .Defogger Timer Operation
Ct Rt Cs
RC Batt GND
TS
N/C N/C Rs Batt
Relay Rear Defogger Resistor
Dz
Toggle Rin S1
Vcc
Batt
MC33187
MOTOROLA
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MC33187
The circuit shown demonstrates the use of the timer to provide a delay in turning the courtesy light off after the vehicle doors are closed. The components are the same as the defogger timer and Rt, Ct, Rs and Cs are as described in the general description above, while Dz and Rin are described in the description of the defogger timer. S1 to Sn represent the doors switches which can be basically the same as for a conventional system, except that only the relay coil current and not the full lamp current passes through them. The operation of the circuit is as follows : While one of the door switches is closed, the courtesy light is on with the relay current owing through the switch.
As soon as the last switch is opened, the energy stored in the relay coil causes the common connection of the switches to rise to the voltage permitted by the clamp consisting of Dz (approximately 16V). This provides a toggle input via Rin, causing the relay output of the integrated circuit to go low, thus keeping the relay energised for the period preset, with the direct connection to Rin ensuring that any switch bounce or noise during this period cannot cause toggle input to be detected. Retriggering at the end of the timing period is prevented by the built in the debounce timer.
Figure 2. Courtesy Light Timer Operation
Ct Cs
Rt
Batt
RC
TS
GND
N/C Batt Rs
Relay Rin S1 Sn Dz Toggle
N/C
Vcc
MC33187
MOTOROLA
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MC33187
This circuit is designed to just use the toggle and relay drive feature of the long duration timer. The functions of components Rs, Cs, Rt, Ct, Rin and Dz are as previously described. Although the circuit is not intended to be allowed to time out, Rt and Ct need to be included as it is necessary for the timer to run for the internal debounce timer to be reset. The control switch S1 needs to be a normally closed momentary type. While it is closed, D1 ensures that the oscillator does not run, while R1 ensures that D1 is reverse biassed when the switch is operated (open). C1 is included to provide a time constant RinC1 to delay the detection of a toggle input. Thus the operation of the circuit is as follows : When S1 is operated, the oscillator is allowed to start ; the toggle input is then recognised and the relay output changes state assuming that the switch has been released, the oscillator is stopped and the sequence above can be repeated. If the switch is held operated for 9 seconds, with the values recommended below, after it has been used to switch the relay
on the circuit will time out and the relay switch off. No further action takes place until the circuit is reset by releasing the button. If the switch is held operated after it has been used to switch the relay off, nothing happens until the circuit is reset by releasing the button. Recommended values : Rs = 1KW Cs = 100nF Rt = 220KW Ct = 10nF Rin = 100KW R1 = 1KW C1 = 220nF Dz = MZD16 D1 = 1N4148 Note that the time constant RtCt and RinC1 are related (start up time and basic frequency of oscillator/switch to toggle delay time) and need to stay in the ratio (1:10).
Figure 3. Relay Drive and Latch (No Timeout)
Ct Rt Cs
D1 RC Batt GND N/C Batt Rs Toggle Rin S1 Vcc TS
Relay Dz C1
N/C
R1
Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. Typical parameters which may be provided in Motorola data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including Typicals must be validated for each customer application by customer's technical experts. Motorola does not convey any license under its patent rights nor the rights of others. Motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury or death may occur. Should Buyer purchase or use Motorola products for any such unintended or unauthorized application, Buyer shall indemnify and hold Motorola and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding the design or manufacture of the part. Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal Opportunity/Affirmative Action Employer.
MC33187
MOTOROLA
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