Features
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•
•
•
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Interval Pause: 4 to 20 s
After-wiping Time: 2 to 20 s
Wiper Motor's Park Switch
Wipe/Wash Mode Priority
One External Capacitor Determines All Time Sequences
Relay Driver with Z-diode
Interference Protection According to VDE 0839 or ISO/TR 7637/1
Load-dump Protected
Description
The U642B is a bi-polar integrated circuit designed for the wiper application in the
automotive market. It includes wipe, wash and internal mode.
Functional Description
As a convenience feature of the windshield wiper, intermittent and wipe/wash operation fuctions are implemented in most of the automobiles. The U642B is a
cost-effective solution for an accurate timing function control. Wipe/wash mode has
priority over interval mode. Interval pause and after-wiping time can be set to fixed values by using resistors in a broad time range. Added value can be provided with an
individual, continuous adjustment of the interval pause by a potentiometer which may
be built into the stalk. For proper operation, it is mandatory to feed the signal of the
wiper motor's park switch into U642B.
Interval- and
Wipe/Wash
Wiper Control
IC
U642B
Figure 1. Block Diagram
VS
PARK
OUT
8
7
WASH
6
5
VRef
VRef
Park switch
comparator
Load-dump
comparator
Input
comparator
VRef
Logic
Wipe/wash
comparator
VRef
Interval
comparator
A
B
C
D
E
F
1
2
3
4
GND
INT
Ct
Rt
Rev. 4774A–AUTO–11/03
Pin Configuration
Figure 2. Pinning
GND
1
8
VS
INT
2
7
OUT
CT
3
6
PARK
RT
4
5
WASH
U642B
Pin Description
2
Pin
Symbol
Function
1
GND
2
INT
Interval switch
3
CT
Timing capacitor C2
4
RT
After-wiping time resistance
5
WASH
6
PARK
Park switch for wiper motor
7
OUT
Relay control output
8
VS
Ground
Wipe/wash switch
Supply voltage terminal 15
U642B
4774A–AUTO–11/03
U642B
Circuit Description
Interval Function, Pin 2
By closing the interval switch, S2, to supply voltage, VBatt, the relay is activated. The
internal current source (pin 3) which holds the capacitor C 2 in a charged state is
switched-off. As soon as there is a positive potential at the park switch (S1), the current
source F (see Figure 1 on page 1) charges the capacitor C2 very quickly. After the wiper
operation is finished, S1 is again at ground potential, the relay is in the off position - interval pause begins - the capacitor C2 is discharged through the current source C, till the
voltage at pin 3 is below the threshold of 2 V. Interval pause can be adjusted between
4 s to 20 s with the help of potentiometer R3. Now the relay switches on and the next
interval cycle begins. Opening of switch S2 causes the current source A to discharge C2
immediately and current sources C and F are switched-off.
Wipe/Wash (WIWA)
Operation, Pin 5
By closing the WIWA switch, S3, to supply voltage, VBatt, the water pump starts spraying
water on the windshield. During this function, the current source A is switched-off which
keeps the capacitor C2 in a discharged state. Now the capacitor is charged through the
current sources D and F. If (after a time interval of approximately 100 ms) the voltage at
the capacitor is greater than 6.5 V, the relay is turned on as long as the switch WIWA is
closed.
The after-wiping time begins when the switch is open, the sources D and F are switched
off and the source E is activated. Source E discharges the capacitor until the voltage is
less than 2.2 V. The relay is off and the wiper-motor is supplied via the park switch until
the park position is reached. The after-wiping time is determined by the current source E
which can be regulated with the external resistor RTime. When the after-wiping time has
elapsed, the source A discharges the capacitor. The relay switch is independent of the
park switch S1.
Interval and WIWA
Functions
The interval function is interrupted immediately when the wipe/wash mode is activated.
The current source A discharges the capacitor to a value of 2 V, afterwards, the normal
wash function starts.
Interval wiping starts immediately when the after-wipe time is over. The switching delays
are slightly shorter, because the capacitor is already charged to a value of 2 V.
The wipe/wash function is not interrupted when the interval switch S2 is activated. The
interval function begins after the WIWA function has elapsed.
3
4774A–AUTO–11/03
Figure 3. Application Circuit with Interval and Wipe/Wash Operation
10 kΩ
7
8
Relay
47 µF
10 V
R6
10 kΩ
R5
6
5
3
4
U642B
C1
1
2
2.7 kΩ
R2
C2
R1
22 µF
R4
510 Ω
Rtime = 130 KΩ
R3
S1
S2
10 kΩ
WIWA
Park
switch
M
M
S3
31
Wiper motor
4
Interval switch
15
Water pump
U642B
4774A–AUTO–11/03
U642B
Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating
only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this
specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Parameters
Pin
Symbol
Value
Unit
Supply voltage t = 60 s, terminal 15
8
VBatt
28
V
Supply current
t = 2 ms
t = 200 ms
8
I8
I8
1.5
150
A
mA
Relay control output current (DC)
t = 200 ms
7
I7
I7
200
1.2
mA
A
I6
I5
I2
50
50
50
mA
Power dissipation Tamb = 90°C
Ptot
500
mW
Storage temperature range
Tstg
-55 to +125
°C
Ambient temperature range
Tamb
-40 to +85
°C
Symbol
Value
Unit
DIP8
RthJA
120
K/W
SO8
RthJA
160
K/W
Pulse Current (Control Inputs) t = 200 ms
6
5
2
Park switch, S1
Wipe/Wash switch, S3
Interval switch, S2
Thermal Resistance
Parameters
Junction ambient
5
4774A–AUTO–11/03
Electrical Characteristics
VBatt = 12 V, Tamb = 25°C, reference point is pin 8 (see Figure 3 on page 4) unless otherwise specified.
Parameters
Test Conditions
Pin
Supply voltage
Symbol
Min.
VBatt
9
Typ.
Max.
16.5
Unit
V
I8
10
mA
V1
7.6
V
Threshold current
I1
-50
mA
Threshold voltage
VBatt
35
V
Supply current
8
Z-diode limitation
Overvoltage
Relay Control Output
Saturation voltage
7
I7 = 100 mA
I7 = 200 mA
100
µA
R6 = 10 kW
R6
50
kW
V6
-3.3
V
I6 = -10 mA
I6 = 10 mA
V6
V6
-0.8
7.6
V
V
R3
100
W
V2
-0.8
7.6
V
V5
-1.4/
-5.4
V
V
-0.8
7.6
V
Park Switch
6
Switching threshold voltage
Protection diode
3
Input Ct
Internal resistance
Interval Input
R2 = 2.7 to 30 kW
Protection diode
I2 = -10 mA
I2 = 30 mA/10 ms
WASH Input
R5 = 10 kW
2
5
Switching threshold/
Hysteresis
Protection diode
I5 = -10 mA
I5 = 10 mA
Switching Characteristics
R4 = 47 kW to 300 kW, I4 = -150 µA
Interval time
R3 = 0 kW
R3 = 10 kW
t2
Prewash delay
After-wipe-time
6
V
I7
Leakage current
Internal pull-up resistance
-1.0
-1.5
V7
3.6
10.8
5
t5
4.4
13.2
100
tdel
R4 = 130 kW
4
12
4.75
5.25
s
ms
5.75
s
U642B
4774A–AUTO–11/03
U642B
Diagrams
Figure 4. Interval Pause = f (T); Ct = 22 µF
12
Interval Pause (s)
Rint = 0
10
Rint = 5 kΩ
8
6
Rint = 10 kΩ
4
2
0
-40
-20
0
20
40
60
80
100
Temperature (°C)
Figure 5. After-wiping Time = f (T); Ct = 22 µF; VBatt = 8 V
Afterwiping Time (s)
12
Rtime = 51 kΩ
10
8
VBatt = 8 V
6
Rtime = 130 kΩ
4
Rtime = 300 kΩ
2
0
-40
-20
0
20
40
60
80
100
Temperature (°C)
Figure 6. Interval Pause = f (RINT); Ct = 22 µF
16
Interval Pause (s)
14
12
10
8
6
4
2
0
0
2
4
6
8
10
12
14
16
18
20
Interval Resistor (kΩ)
7
4774A–AUTO–11/03
Figure 7. After-wiping Time = f (T); Ct = 22 µF; VBatt = 16 V
Afterwiping Time (s)
12
Rtime = 51 kΩ
10
8
VBatt = 16 V
Rtime = 130 kΩ
6
4
Rtime = 300 kΩ
2
0
-40
-20
0
20
40
60
80
100
Temperature (°C)
8
U642B
4774A–AUTO–11/03
U642B
Ordering Information
Extended Type Number
Package
Remarks
U642B
DIP8
–
U642B-FP
SO8
–
Package Information
Package DIP8
Dimensions in mm
7.77
7.47
9.8
9.5
1.64
1.44
4.8 max
6.4 max
0.5 min 3.3
0.58
0.48
0.36 max
9.8
8.2
2.54
7.62
8
5
technical drawings
according to DIN
specifications
1
4
Package SO8
Dimensions in mm
5.2
4.8
5.00
4.85
3.7
1.4
0.25
0.10
0.4
1.27
6.15
5.85
3.81
8
0.2
3.8
5
technical drawings
according to DIN
specifications
1
4
9
4774A–AUTO–11/03
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4774A–AUTO–11/03